rebuilt docs

Former-commit-id: 6fd0ba1ed2c27c6a970460e2b34b4d23b3e46cda

.circleci/config.yml

@@ -0,0 +1,85 @@
+# Javascript Node CircleCI 2.0 configuration file
+#
+# Check https://circleci.com/docs/2.0/language-javascript/ for more details
+#
+version: 2
+jobs:
+  build:
+    docker:
+      # specify the version you desire here
+      - image: circleci/node:11.14.0
+
+    working_directory: ~/semaphore_private/
+
+    steps:
+      - checkout:
+          path: ~/semaphore_private/
+
+      - run:
+          name: Install solc
+          command: wget https://github.com/ethereum/solidity/releases/download/v0.5.12/solc-static-linux && chmod a+x solc-static-linux && sudo mv solc-static-linux /usr/bin/solc
+
+      - restore_cache:
+          keys:
+            - v1.9-dependencies-{{ checksum "package-lock.json" }}
+
+      - run: npm install
+
+      - save_cache:
+          paths:
+            - node_modules
+          key: v1.9-dependencies-{{ checksum "package-lock.json" }}
+
+      - restore_cache:
+          keys:
+            - v1.9-dependencies-{{ checksum "contracts/package-lock.json" }}-{{ checksum "circuits/package-lock.json" }}-{{ checksum "config/package-lock.json" }}
+
+      - run: npm run bootstrap && npm run build
+
+      - save_cache:
+          paths:
+            - contracts/node_modules
+            - config/node_modules
+            - circuits/node_modules
+          key: v1.8-dependencies-{{ checksum "contracts/package-lock.json" }}-{{ checksum "circuits/package-lock.json" }}-{{ checksum "config/package-lock.json" }}
+
+      # checksum the snarks definitions
+      - run:
+          name: Checksum snark files
+          command: cd circuits/ && ./scripts/checksum_snarks.sh
+
+      - restore_cache:
+          name: restore-snark-cache
+          keys:
+            - v1.9-dependencies-{{ checksum "circuits/build/.snark_checksum" }}
+
+      # build snarks
+      - run:
+          name: Build snark files
+          command: cd circuits && ./scripts/build_snarks.sh
+          no_output_timeout: 600m
+
+      # cache generated snark circuit and keys
+      - save_cache:
+          key: v1.9-dependencies-{{ checksum "circuits/build/.snark_checksum" }}
+          paths:
+            - circuits/build/circuit.json
+            - circuits/build/proving_key.bin
+            - circuits/build/proving_key.json
+            - circuits/build/verification_key.json
+            - circuits/build/verifier.sol
+
+      - run:
+          name: Compile contracts
+          command: cd contracts && npm run compileSol
+
+      - run:
+          name: Run circuit tests
+          command: cd circuits && ./scripts/runTestsInCircleCi.sh
+
+      - run:
+          name: Run contract tests
+          command: cd contracts && ./scripts/runTestsInCircleCi.sh
+
+      - store_artifacts:
+          path: circuits/build

.commitlintrc.json

@@ -1,3 +0,0 @@
-{
-    "extends": ["@commitlint/config-conventional"]
-}

.editorconfig

@@ -1,13 +0,0 @@
-#root = true
-
-[*]
-indent_style = space
-end_of_line = lf
-charset = utf-8
-trim_trailing_whitespace = true
-insert_final_newline = true
-max_line_length = 120
-indent_size = 4
-
-[*.md]
-trim_trailing_whitespace = false

.env.example

@@ -1,8 +0,0 @@
-DEFAULT_NETWORK=hardhat
-TREE_DEPTH=20
-ALL_SNARK_ARTIFACTS=true
-REPORT_GAS=false
-BACKEND_PRIVATE_KEY=
-INFURA_API_KEY=
-COINMARKETCAP_API_KEY=
-ETHERSCAN_API_KEY=

.eslintignore

@@ -1,32 +0,0 @@
-# dependencies
-node_modules
-package-lock.json
-yarn.lock
-.yarn
-
-# testing
-coverage
-coverage.json
-
-# hardhat
-cache
-
-# types
-types
-
-# circuits
-circuits
-
-# production
-dist
-build
-docs
-
-# misc
-.DS_Store
-*.pem
-
-# debug
-npm-debug.log*
-yarn-debug.log*
-yarn-error.log*

.eslintrc.json

@@ -1,24 +0,0 @@
-{
-    "root": true,
-    "env": {
-        "es6": true
-    },
-    "extends": ["airbnb-base", "airbnb-typescript/base", "plugin:jest/recommended", "plugin:jest/style", "prettier"],
-    "parser": "@typescript-eslint/parser",
-    "parserOptions": {
-        "ecmaVersion": 6,
-        "sourceType": "module",
-        "project": ["./tsconfig.json", "./packages/**/tsconfig.json"]
-    },
-    "plugins": ["@typescript-eslint", "jest"],
-    "rules": {
-        "no-underscore-dangle": "off",
-        "import/no-extraneous-dependencies": "off",
-        "no-bitwise": "off",
-        "no-await-in-loop": "off",
-        "no-restricted-syntax": "off",
-        "no-console": ["warn", { "allow": ["info", "warn", "error"] }],
-        "@typescript-eslint/lines-between-class-members": "off",
-        "no-param-reassign": "off"
-    }
-}

.github/ISSUE_TEMPLATE/----network.md

@@ -1,18 +0,0 @@
----
-name: "\U0001F578️ Network"
-about: Propose a new network in which to deploy Semaphore contracts
-title: ''
-labels: ''
-assignees: ''
-
----
-
-**Provide data related to the network**
-
-* Name
-* Chain id
-* URL
-
-**Why are you using this network?**
-
-Describe the reasons why you think it is important for Semaphore to be deployed on this network.

.github/ISSUE_TEMPLATE/----project.md

@@ -1,22 +0,0 @@
----
-name: " \U0001F4A0 Project"
-about: If you are using Semaphore we can help you share your project
-title: ''
-labels: "documentation  \U0001F4D6"
-assignees: ''
-
----
-
-**Describe your project**
-A brief description of your project. In what way have you used Semaphore?
-
-**Other info**
-
--   Name
--   Icon
-
-**Links**
-
--   Website
--   Github
--   Socials

.github/ISSUE_TEMPLATE/---bug.md

@@ -1,34 +0,0 @@
----
-name: "\U0001F41E Bug"
-about: Create a report to help us improve
-title: ''
-labels: "bug \U0001F41B"
-assignees: ''
-
----
-
-**Describe the bug**
-A clear and concise description of what the bug is.
-
-**To Reproduce**
-Steps to reproduce the behavior:
-
-1. Go to '...'
-2. Click on '....'
-3. Scroll down to '....'
-4. See error
-
-**Expected behavior**
-A clear and concise description of what you expected to happen.
-
-**Screenshots**
-If applicable, add screenshots to help explain your problem.
-
-**Technologies (please complete the following information):**
-
--   Node.js version
--   NPM version
--   Solidity version
-
-**Additional context**
-Add any other context about the problem here.

.github/ISSUE_TEMPLATE/---feature.md

@@ -1,20 +0,0 @@
----
-name: "\U0001F680 Feature"
-about: Suggest an idea for Semaphore
-title: ''
-labels: 'feature :rocket:'
-assignees: ''
-
----
-
-**Is your feature request related to a problem? Please describe.**
-A clear and concise description of what the problem is. Ex. I'm always frustrated when [...]
-
-**Describe the solution you'd like**
-A clear and concise description of what you want to happen.
-
-**Describe alternatives you've considered**
-A clear and concise description of any alternative solutions or features you've considered.
-
-**Additional context**
-Add any other context or screenshots about the feature request here.

.github/ISSUE_TEMPLATE/---package.md

@@ -1,14 +0,0 @@
----
-name: "\U0001F4E6 Package"
-about: Propose a new Semaphore package
-title: ''
-labels: 'feature :rocket:'
-assignees: ''
-
----
-
-**Describe the package you'd like**
-A clear and concise description of the type of package you have in mind.
-
-**Additional context**
-Add any other context about the package here.

.github/pull_request_template.md

@@ -1,24 +0,0 @@
-<!-- Please refer to our contributing documentation for any questions on submitting a pull request -->
-<!--- Provide a general summary of your changes in the Title above -->
-
-## Description
-
-<!--- Describe your changes in detail -->
-
-## Related Issue
-
-<!--- This project accepts pull requests related to open issues -->
-<!--- If suggesting a new feature or change, please discuss it in an issue first -->
-<!--- If fixing a bug, there should be an issue describing it with steps to reproduce -->
-<!--- Please link to the issue here: -->
-
-## Does this introduce a breaking change?
-
--   [ ] Yes
--   [ ] No
-
-<!-- If this introduces a breaking change, please describe the impact and migration path for existing applications below. -->
-
-## Other information
-
-<!-- Any other information that is important to this PR such as screenshots of how the component looks before and after the change. -->

.github/workflows/docs.yml

@@ -1,45 +0,0 @@
-name: docs
-
-on:
-    push:
-        branches:
-            - main
-
-jobs:
-    gh-pages:
-        runs-on: ubuntu-latest
-
-        steps:
-            - uses: actions/checkout@v2
-
-            - name: Install Node.js
-              uses: actions/setup-node@v1
-              with:
-                  node-version: 16.x
-
-            - name: Get yarn cache directory path
-              id: yarn-cache-dir-path
-              run: echo "::set-output name=dir::$(yarn config get cacheFolder)"
-
-            - name: Restore yarn cache
-              uses: actions/cache@v3
-              id: yarn-cache
-              with:
-                  path: ${{ steps.yarn-cache-dir-path.outputs.dir }}
-                  key: ${{ runner.os }}-yarn-${{ hashFiles('**/yarn.lock') }}
-                  restore-keys: |
-                      ${{ runner.os }}-yarn-
-
-            - name: Install dependencies
-              run: yarn
-
-            - name: Generate doc website
-              run: yarn docs
-
-            - name: Publish on Github Pages
-              uses: crazy-max/ghaction-github-pages@v2.5.0
-              with:
-                  build_dir: docs
-                  jekyll: false
-              env:
-                  GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

.github/workflows/production.yml

@@ -1,107 +0,0 @@
-name: production
-
-on:
-    push:
-        branches:
-            - main
-
-env:
-    TREE_DEPTH: 20
-    ALL_SNARK_ARTIFACTS: false
-
-jobs:
-    style:
-        runs-on: ubuntu-latest
-
-        steps:
-            - uses: actions/checkout@v2
-
-            - name: Install Node.js
-              uses: actions/setup-node@v1
-              with:
-                  node-version: 16.x
-
-            - name: Get yarn cache directory path
-              id: yarn-cache-dir-path
-              run: echo "::set-output name=dir::$(yarn config get cacheFolder)"
-
-            - name: Restore yarn cache
-              uses: actions/cache@v3
-              id: yarn-cache
-              with:
-                  path: ${{ steps.yarn-cache-dir-path.outputs.dir }}
-                  key: ${{ runner.os }}-yarn-${{ hashFiles('**/yarn.lock') }}
-                  restore-keys: |
-                      ${{ runner.os }}-yarn-
-
-            - name: Install dependencies
-              run: yarn
-
-            - name: Compile contracts
-              run: yarn compile:contracts
-
-            - name: Build libraries
-              run: yarn build:libraries
-
-            - name: Run Prettier
-              run: yarn prettier
-
-            - name: Run Eslint
-              run: yarn lint
-
-    test:
-        runs-on: ubuntu-latest
-        strategy:
-            matrix:
-                type:
-                    - libraries
-                    - contracts
-
-        steps:
-            - uses: actions/checkout@v2
-
-            - name: Install Node.js
-              uses: actions/setup-node@v1
-              with:
-                  node-version: 16.x
-
-            - name: Get yarn cache directory path
-              id: yarn-cache-dir-path
-              run: echo "::set-output name=dir::$(yarn config get cacheFolder)"
-
-            - name: Restore yarn cache
-              uses: actions/cache@v3
-              id: yarn-cache
-              with:
-                  path: ${{ steps.yarn-cache-dir-path.outputs.dir }}
-                  key: ${{ runner.os }}-yarn-${{ hashFiles('**/yarn.lock') }}
-                  restore-keys: |
-                      ${{ runner.os }}-yarn-
-
-            - name: Install dependencies
-              run: yarn
-
-            - name: Build libraries
-              run: yarn build:libraries
-
-            - name: Test contracts and libraries
-              run: yarn test:${{ matrix.type }}
-
-            - name: Coveralls
-              uses: coverallsapp/github-action@master
-              with:
-                  github-token: ${{ secrets.GITHUB_TOKEN }}
-                  flag-name: run-${{ matrix.type }}
-                  path-to-lcov: ./coverage/${{ matrix.type }}/lcov.info
-                  parallel: true
-
-    coverage:
-        runs-on: ubuntu-latest
-        needs: test
-
-        steps:
-            - name: Coveralls Finished
-              uses: coverallsapp/github-action@master
-              with:
-                  github-token: ${{ secrets.GITHUB_TOKEN }}
-                  parallel-finished: true

.github/workflows/pull-requests.yml

@@ -1,81 +0,0 @@
-name: pull-requests
-
-on:
-    pull_request:
-
-env:
-    TREE_DEPTH: 20
-    ALL_SNARK_ARTIFACTS: false
-
-jobs:
-    style:
-        runs-on: ubuntu-latest
-
-        steps:
-            - uses: actions/checkout@v2
-
-            - name: Install Node.js
-              uses: actions/setup-node@v1
-              with:
-                  node-version: 16.x
-
-            - name: Get yarn cache directory path
-              id: yarn-cache-dir-path
-              run: echo "::set-output name=dir::$(yarn config get cacheFolder)"
-
-            - name: Restore yarn cache
-              uses: actions/cache@v3
-              id: yarn-cache
-              with:
-                  path: ${{ steps.yarn-cache-dir-path.outputs.dir }}
-                  key: ${{ runner.os }}-yarn-${{ hashFiles('**/yarn.lock') }}
-                  restore-keys: |
-                      ${{ runner.os }}-yarn-
-
-            - name: Install dependencies
-              run: yarn
-
-            - name: Compile contracts
-              run: yarn compile:contracts
-
-            - name: Build libraries
-              run: yarn build:libraries
-
-            - name: Run Prettier
-              run: yarn prettier
-
-            - name: Run Eslint
-              run: yarn lint
-
-    test:
-        runs-on: ubuntu-latest
-
-        steps:
-            - uses: actions/checkout@v2
-
-            - name: Install Node.js
-              uses: actions/setup-node@v1
-              with:
-                  node-version: 16.x
-
-            - name: Get yarn cache directory path
-              id: yarn-cache-dir-path
-              run: echo "::set-output name=dir::$(yarn config get cacheFolder)"
-
-            - name: Restore yarn cache
-              uses: actions/cache@v3
-              id: yarn-cache
-              with:
-                  path: ${{ steps.yarn-cache-dir-path.outputs.dir }}
-                  key: ${{ runner.os }}-yarn-${{ hashFiles('**/yarn.lock') }}
-                  restore-keys: |
-                      ${{ runner.os }}-yarn-
-
-            - name: Install dependencies
-              run: yarn
-
-            - name: Build libraries
-              run: yarn build:libraries
-
-            - name: Test contracts and libraries
-              run: yarn test

.gitignore

@@ -1,90 +1,8 @@
-# Logs
-logs
-*.log
-npm-debug.log*
-yarn-debug.log*
-yarn-error.log*
-lerna-debug.log*
-.pnpm-debug.log*
-
-# Diagnostic reports (https://nodejs.org/api/report.html)
-report.[0-9]*.[0-9]*.[0-9]*.[0-9]*.json
-
-# Runtime data
-pids
-*.pid
-*.seed
-*.pid.lock
-
-# IDE
-.vscode
-.idea
-
-# Testing
-coverage
-coverage.json
-*.lcov
-
-# Dependency directories
-node_modules/
-
-# TypeScript cache
-*.tsbuildinfo
-
-# Optional npm cache directory
-.npm
-.DS_Store
-
-# Output of 'npm pack'
-*.tgz
-
-# Optional eslint cache
-.eslintcache
-
-# Microbundle cache
-.rpt2_cache/
-.rts2_cache_cjs/
-.rts2_cache_es/
-.rts2_cache_umd/
-
-# Output of 'npm pack'
-*.tgz
-
-# Yarn Integrity file
-.yarn-integrity
-
-# dotenv environment variable files
-.env
-.env.development.local
-.env.test.local
-.env.production.local
-.env.local
-
-# Production
-build
-dist
-docs/*
-!docs/CNAME
-!docs/index.html
-
-# Hardhat
-artifacts
-cache
-packages/contracts/deployed-contracts/undefined.json
-packages/contracts/deployed-contracts/hardhat.json
-packages/contracts/deployed-contracts/localhost.json
-
-# Stores VSCode versions used for testing VSCode extensions
-.vscode-test
-
-# yarn v3
-.pnp.*
-.yarn/*
-!.yarn/patches
-!.yarn/plugins
-!.yarn/releases
-!.yarn/sdks
-!.yarn/versions
-
-# Other
-snark-artifacts
+docs_src/book/
+.etherlime-store
+**/build/
+circuits/build
+contracts/compiled
+node_modules
+blake2sdef.json
+build/.snark_checksum

.lintstagedrc.json

@@ -1,3 +0,0 @@
-{
-    "**/*.{js,ts}": ["prettier --write", "eslint --fix"]
-}

.prettierignore

@@ -1,44 +0,0 @@
-# dependencies
-node_modules
-package-lock.json
-yarn.lock
-.yarn
-
-# testing
-coverage
-coverage.json
-
-# hardhat
-cache
-packages/contracts/deployed-contracts/undefined.json
-packages/contracts/deployed-contracts/hardhat.json
-packages/contracts/deployed-contracts/localhost.json
-
-# types
-types
-
-# circuits
-circuits
-
-# contracts
-Verifier*.sol
-
-# production
-dist
-build
-docs
-
-# github
-.github/ISSUE_TEMPLATE
-
-# misc
-.DS_Store
-*.pem
-
-# debug
-npm-debug.log*
-yarn-debug.log*
-yarn-error.log*
-
-# other
-snark-artifacts

.prettierrc.json

@@ -1,5 +0,0 @@
-{
-    "semi": false,
-    "arrowParens": "always",
-    "trailingComma": "none"
-}

.yarn/releases/yarn-3.2.1.cjs.REMOVED.git-id

@@ -1 +0,0 @@
-b3cadff6efb37a12712d12c2553ec703dbcaa4dd

.yarnrc.yml

@@ -1,8 +0,0 @@
-nodeLinker: node-modules
-checksumBehavior: update
-
-plugins:
-    - path: .yarn/plugins/@yarnpkg/plugin-workspace-tools.cjs
-      spec: "@yarnpkg/plugin-workspace-tools"
-
-yarnPath: .yarn/releases/yarn-3.2.1.cjs

CODE_OF_CONDUCT.md

@@ -1,127 +0,0 @@
-# Contributor Covenant Code of Conduct
-
-## Our Pledge
-
-We as members, contributors, and leaders pledge to make participation in our
-community a harassment-free experience for everyone, regardless of age, body
-size, visible or invisible disability, ethnicity, sex characteristics, gender
-identity and expression, level of experience, education, socio-economic status,
-nationality, personal appearance, race, religion, or sexual identity
-and orientation.
-
-We pledge to act and interact in ways that contribute to an open, welcoming,
-diverse, inclusive, and healthy community.
-
-## Our Standards
-
-Examples of behavior that contributes to a positive environment for our
-community include:
-
--   Demonstrating empathy and kindness toward other people
--   Being respectful of differing opinions, viewpoints, and experiences
--   Giving and gracefully accepting constructive feedback
--   Accepting responsibility and apologizing to those affected by our mistakes,
-    and learning from the experience
--   Focusing on what is best not just for us as individuals, but for the
-    overall community
-
-Examples of unacceptable behavior include:
-
--   The use of sexualized language or imagery, and sexual attention or
-    advances of any kind
--   Trolling, insulting or derogatory comments, and personal or political attacks
--   Public or private harassment
--   Publishing others' private information, such as a physical or email
-    address, without their explicit permission
--   Other conduct which could reasonably be considered inappropriate in a
-    professional setting
-
-## Enforcement Responsibilities
-
-Community leaders are responsible for clarifying and enforcing our standards of
-acceptable behavior and will take appropriate and fair corrective action in
-response to any behavior that they deem inappropriate, threatening, offensive,
-or harmful.
-
-Community leaders have the right and responsibility to remove, edit, or reject
-comments, commits, code, wiki edits, issues, and other contributions that are
-not aligned to this Code of Conduct, and will communicate reasons for moderation
-decisions when appropriate.
-
-## Scope
-
-This Code of Conduct applies within all community spaces, and also applies when
-an individual is officially representing the community in public spaces.
-Examples of representing our community include using an official e-mail address,
-posting via an official social media account, or acting as an appointed
-representative at an online or offline event.
-
-## Enforcement
-
-Instances of abusive, harassing, or otherwise unacceptable behavior may be
-reported to the community leaders responsible for enforcement.
-All complaints will be reviewed and investigated promptly and fairly.
-
-All community leaders are obligated to respect the privacy and security of the
-reporter of any incident.
-
-## Enforcement Guidelines
-
-Community leaders will follow these Community Impact Guidelines in determining
-the consequences for any action they deem in violation of this Code of Conduct:
-
-### 1. Correction
-
-**Community Impact**: Use of inappropriate language or other behavior deemed
-unprofessional or unwelcome in the community.
-
-**Consequence**: A private, written warning from community leaders, providing
-clarity around the nature of the violation and an explanation of why the
-behavior was inappropriate. A public apology may be requested.
-
-### 2. Warning
-
-**Community Impact**: A violation through a single incident or series
-of actions.
-
-**Consequence**: A warning with consequences for continued behavior. No
-interaction with the people involved, including unsolicited interaction with
-those enforcing the Code of Conduct, for a specified period of time. This
-includes avoiding interactions in community spaces as well as external channels
-like social media. Violating these terms may lead to a temporary or
-permanent ban.
-
-### 3. Temporary Ban
-
-**Community Impact**: A serious violation of community standards, including
-sustained inappropriate behavior.
-
-**Consequence**: A temporary ban from any sort of interaction or public
-communication with the community for a specified period of time. No public or
-private interaction with the people involved, including unsolicited interaction
-with those enforcing the Code of Conduct, is allowed during this period.
-Violating these terms may lead to a permanent ban.
-
-### 4. Permanent Ban
-
-**Community Impact**: Demonstrating a pattern of violation of community
-standards, including sustained inappropriate behavior, harassment of an
-individual, or aggression toward or disparagement of classes of individuals.
-
-**Consequence**: A permanent ban from any sort of public interaction within
-the community.
-
-## Attribution
-
-This Code of Conduct is adapted from the [Contributor Covenant][homepage],
-version 2.0, available at
-https://www.contributor-covenant.org/version/2/0/code_of_conduct.html.
-
-Community Impact Guidelines were inspired by [Mozilla's code of conduct
-enforcement ladder](https://github.com/mozilla/diversity).
-
-[homepage]: https://www.contributor-covenant.org
-
-For answers to common questions about this code of conduct, see the FAQ at
-https://www.contributor-covenant.org/faq. Translations are available at
-https://www.contributor-covenant.org/translations.

CONTRIBUTING.md

@@ -1,111 +0,0 @@
-# Contributing
-
-:tada: Thank you for being interested in contributing to the Semaphore project! :tada:
-
-Feel welcome and read the following sections in order to know how to ask questions and how to work on something.
-
-All members of our community are expected to follow our [Code of Conduct](/CODE_OF_CONDUCT.md). Please make sure you are welcoming and friendly in all of our spaces.
-
-We're really glad you're reading this, because we need volunteer developers to help this project come to fruition. 👏
-
-## Issues
-
-The best way to contribute to our projects is by opening a [new issue](https://github.com/semaphore-protocol/semaphore/issues/new/choose) or tackling one of the issues listed [here](https://github.com/semaphore-protocol/semaphore/contribute).
-
-## Pull Requests
-
-Pull requests are great if you want to add a feature or fix a bug. Here's a quick guide:
-
-1. Fork the repo.
-
-2. Run the tests. We only take pull requests with passing tests.
-
-3. Add a test for your change. Only refactoring and documentation changes require no new tests.
-
-4. Make sure to check out the [Style Guide](/CONTRIBUTING#style-guide) and ensure that your code complies with the rules.
-
-5. Make the test pass.
-
-6. Commit your changes.
-
-7. Push to your fork and submit a pull request on our `dev` branch. Please provide us with some explanation of why you made the changes you made. For new features make sure to explain a standard use case to us.
-
-## CI (Github Actions) Tests
-
-We use GitHub Actions to test each PR before it is merged.
-
-When you submit your PR (or later change that code), a CI build will automatically be kicked off. A note will be added to the PR, and will indicate the current status of the build.
-
-## Style Guide
-
-### Code rules
-
-We always use ESLint and Prettier. To check that your code follows the rules, simply run the npm script `yarn lint`.
-
-### Commits rules
-
-For commits it is recommended to use [Conventional Commits](https://www.conventionalcommits.org).
-
-Don't worry if it looks complicated, in our repositories, after `git add`, you can usually run the npm script `yarn commit` to make many of these steps interactive.
-
-Each commit message consists of a **header**, a **body** and a **footer**. The **header** has a special format that includes a **type**, a **scope** and a **subject**:
-
-    <type>(<scope>): <subject>
-    <BLANK LINE>
-    <body>
-    <BLANK LINE>
-    <footer>
-
-The **header** is mandatory and the **scope** of the header must contain the name of the package you are working on.
-
-#### Type
-
-The type must be one of the following:
-
--   feat: A new feature
--   fix: A bug fix
--   docs: Documentation only changes
--   style: Changes that do not affect the meaning of the code (white-space, formatting, missing semi-colons, etc)
--   refactor: A code change that neither fixes a bug nor adds a feature (improvements of the code structure)
--   perf: A code change that improves the performance
--   test: Adding missing or correcting existing tests
--   build: Changes that affect the build system or external dependencies (example scopes: gulp, npm)
--   ci: Changes to CI configuration files and scripts (example scopes: travis, circle)
--   chore: Other changes that don't modify src or test files
--   revert: Reverts a previous commit
-
-#### Scope
-
-The scope should be the name of the npm package affected (as perceived by the person reading the changelog generated from commit messages).
-
-#### Subject
-
-The subject contains a succinct description of the change:
-
--   Use the imperative, present tense: "change" not "changed" nor "changes"
--   Don't capitalize the first letter
--   No dot (.) at the end
-
-#### Body
-
-Just as in the subject, use the imperative, present tense: "change" not "changed" nor "changes". The body should include the motivation for the change and contrast this with previous behavior.
-
-### Branch rules
-
--   There must be a `main` branch, used only for the releases.
--   There must be a `dev` branch, used to merge all the branches under it.
--   Avoid long descriptive names for long-lived branches.
--   Use kebab-case (no CamelCase).
--   Use grouping tokens (words) at the beginning of your branch names (in a similar way to the `type` of commit).
--   Define and use short lead tokens to differentiate branches in a way that is meaningful to your workflow.
--   Use slashes to separate parts of your branch names.
--   Remove branch after merge if it is not important.
-
-Examples:
-
-```bash
-git branch -b docs/readme
-git branch -b test/a-feature
-git branch -b feat/sidebar
-git branch -b fix/b-feature
-```

LICENSE

@@ -1,21 +0,0 @@
-MIT License
-
-Copyright (c) 2022 Ethereum Foundation
-
-Permission is hereby granted, free of charge, to any person obtaining a copy
-of this software and associated documentation files (the "Software"), to deal
-in the Software without restriction, including without limitation the rights
-to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-copies of the Software, and to permit persons to whom the Software is
-furnished to do so, subject to the following conditions:
-
-The above copyright notice and this permission notice shall be included in all
-copies or substantial portions of the Software.
-
-THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
-SOFTWARE.

README.md

@@ -1,307 +1,12 @@
-<p align="center">
-    <h1 align="center">
-      <picture>
-        <source media="(prefers-color-scheme: dark)" srcset="https://github.com/semaphore-protocol/website/blob/main/static/img/semaphore-icon-dark.svg">
-        <source media="(prefers-color-scheme: light)" srcset="https://github.com/semaphore-protocol/website/blob/main/static/img/semaphore-icon.svg">
-        <img width="40" alt="Semaphore icon." src="https://github.com/semaphore-protocol/website/blob/main/static/img/semaphore-icon.svg">
-      </picture>
-      Semaphore
-    </h1>
-</p>
+# Semaphore
 
-<p align="center">
-    <a href="https://github.com/semaphore-protocol" target="_blank">
-        <img src="https://img.shields.io/badge/project-Semaphore-blue.svg?style=flat-square">
-    </a>
-    <a href="/LICENSE">
-        <img alt="Github license" src="https://img.shields.io/github/license/semaphore-protocol/semaphore.svg?style=flat-square">
-    </a>
-    <a href="https://github.com/semaphore-protocol/semaphore/actions?query=workflow%3Aproduction">
-        <img alt="GitHub Workflow test" src="https://img.shields.io/github/workflow/status/semaphore-protocol/semaphore/production?label=test&style=flat-square&logo=github">
-    </a>
-    <a href="https://coveralls.io/github/semaphore-protocol/semaphore">
-        <img alt="Coveralls" src="https://img.shields.io/coveralls/github/semaphore-protocol/semaphore?style=flat-square&logo=coveralls">
-    </a>
-    <a href="https://deepscan.io/dashboard#view=project&tid=16502&pid=22324&bid=657461">
-        <img src="https://deepscan.io/api/teams/16502/projects/22324/branches/657461/badge/grade.svg" alt="DeepScan grade">
-    </a>
-    <a href="https://eslint.org/">
-        <img alt="Linter eslint" src="https://img.shields.io/badge/linter-eslint-8080f2?style=flat-square&logo=eslint">
-    </a>
-    <a href="https://prettier.io/">
-        <img alt="Code style prettier" src="https://img.shields.io/badge/code%20style-prettier-f8bc45?style=flat-square&logo=prettier">
-    </a>
-    <img alt="Repository top language" src="https://img.shields.io/github/languages/top/semaphore-protocol/semaphore?style=flat-square">
-</p>
+Semaphore is a zero-knowledge gadget which allows users to prove their
+membership of a set without revealing their original identity. At the same
+time, it allows users to signal their endorsement of an arbitrary string. It is
+designed to be a simple and generic privacy layer for Ethereum dApps. Use cases
+include private voting, whistleblowing, mixers, and anonymous authentication.
 
-<div align="center">
-    <h4>
-        <a href="/CONTRIBUTING.md">
-            👥 Contributing
-        </a>
-        <span>&nbsp;&nbsp;|&nbsp;&nbsp;</span>
-        <a href="/CODE_OF_CONDUCT.md">
-            🤝 Code of conduct
-        </a>
-        <span>&nbsp;&nbsp;|&nbsp;&nbsp;</span>
-        <a href="https://github.com/semaphore-protocol/semaphore/contribute">
-            🔎 Issues
-        </a>
-        <span>&nbsp;&nbsp;|&nbsp;&nbsp;</span>
-        <a href="https://discord.gg/6mSdGHnstH">
-            🗣️ Chat &amp; Support
-        </a>
-    </h4>
-</div>
+For more information, refer to the
+[documentation](https://appliedzkp.github.io/semaphore/).
 
-| Semaphore is a protocol, designed to be a simple and generic privacy layer for Ethereum DApps. Using zero knowledge, Ethereum users can prove their membership of a group and send signals such as votes or endorsements without revealing their original identity. |
-| ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
-
-The core of the Semaphore protocol is in the [circuit logic](/packages/circuits/scheme.png). However Semaphore also provides [Solidity contracts](/packages/contracts) (NPM: `@semaphore-protocol/contracts`) and JavaScript libraries to make the steps for offchain proof creation and onchain verification easier. To learn more about Semaphore visit [semaphore.appliedzkp.org](https://semaphore.appliedzkp.org).
-
-You can find Semaphore V1 on [`version/1.0.0`](https://github.com/semaphore-protocol/semaphore/tree/version/1.0.0).
-
----
-
-## 📦 Packages
-
-<table>
-    <th>Package</th>
-    <th>Version</th>
-    <th>Downloads</th>
-    <tbody>
-        <tr>
-            <td>
-                <a href="/packages/contracts">
-                    @semaphore-protocol/contracts
-                </a>
-            </td>
-            <td>
-                <!-- NPM version -->
-                <a href="https://npmjs.org/package/@semaphore-protocol/contracts">
-                    <img src="https://img.shields.io/npm/v/@semaphore-protocol/contracts.svg?style=flat-square" alt="NPM version" />
-                </a>
-            </td>
-            <td>
-                <!-- Downloads -->
-                <a href="https://npmjs.org/package/@semaphore-protocol/contracts">
-                    <img src="https://img.shields.io/npm/dm/@semaphore-protocol/contracts.svg?style=flat-square" alt="Downloads" />
-                </a>
-            </td>
-        </tr>
-        <tr>
-            <td>
-                <a href="/packages/identity">
-                    @semaphore-protocol/identity
-                </a>
-                <a href="https://semaphore-protocol.github.io/semaphore/identity">
-                    (docs)
-                </a>
-            </td>
-            <td>
-                <!-- NPM version -->
-                <a href="https://npmjs.org/package/@semaphore-protocol/identity">
-                    <img src="https://img.shields.io/npm/v/@semaphore-protocol/identity.svg?style=flat-square" alt="NPM version" />
-                </a>
-            </td>
-            <td>
-                <!-- Downloads -->
-                <a href="https://npmjs.org/package/@semaphore-protocol/identity">
-                    <img src="https://img.shields.io/npm/dm/@semaphore-protocol/identity.svg?style=flat-square" alt="Downloads" />
-                </a>
-            </td>
-        </tr>
-        <tr>
-            <td>
-                <a href="/packages/group">
-                    @semaphore-protocol/group
-                </a>
-                <a href="https://semaphore-protocol.github.io/semaphore/group">
-                    (docs)
-                </a>
-            </td>
-            <td>
-                <!-- NPM version -->
-                <a href="https://npmjs.org/package/@semaphore-protocol/group">
-                    <img src="https://img.shields.io/npm/v/@semaphore-protocol/group.svg?style=flat-square" alt="NPM version" />
-                </a>
-            </td>
-            <td>
-                <!-- Downloads -->
-                <a href="https://npmjs.org/package/@semaphore-protocol/group">
-                    <img src="https://img.shields.io/npm/dm/@semaphore-protocol/group.svg?style=flat-square" alt="Downloads" />
-                </a>
-            </td>
-        </tr>
-        <tr>
-            <td>
-                <a href="/packages/proof">
-                    @semaphore-protocol/proof
-                </a>
-                <a href="https://semaphore-protocol.github.io/semaphore/proof">
-                    (docs)
-                </a>
-            </td>
-            <td>
-                <!-- NPM version -->
-                <a href="https://npmjs.org/package/@semaphore-protocol/proof">
-                    <img src="https://img.shields.io/npm/v/@semaphore-protocol/proof.svg?style=flat-square" alt="NPM version" />
-                </a>
-            </td>
-            <td>
-                <!-- Downloads -->
-                <a href="https://npmjs.org/package/@semaphore-protocol/proof">
-                    <img src="https://img.shields.io/npm/dm/@semaphore-protocol/proof.svg?style=flat-square" alt="Downloads" />
-                </a>
-            </td>
-        </tr>
-        <tr>
-            <td>
-                <a href="/packages/subgraph">
-                    @semaphore-protocol/subgraph
-                </a>
-                <a href="https://semaphore-protocol.github.io/semaphore/subgraph">
-                    (docs)
-                </a>
-            </td>
-            <td>
-                <!-- NPM version -->
-                <a href="https://npmjs.org/package/@semaphore-protocol/subgraph">
-                    <img src="https://img.shields.io/npm/v/@semaphore-protocol/subgraph.svg?style=flat-square" alt="NPM version" />
-                </a>
-            </td>
-            <td>
-                <!-- Downloads -->
-                <a href="https://npmjs.org/package/@semaphore-protocol/subgraph">
-                    <img src="https://img.shields.io/npm/dm/@semaphore-protocol/subgraph.svg?style=flat-square" alt="Downloads" />
-                </a>
-            </td>
-        </tr>
-        <tr>
-            <td>
-                <a href="/packages/hardhat">
-                    @semaphore-protocol/hardhat
-                </a>
-            </td>
-            <td>
-                <!-- NPM version -->
-                <a href="https://npmjs.org/package/@semaphore-protocol/hardhat">
-                    <img src="https://img.shields.io/npm/v/@semaphore-protocol/hardhat.svg?style=flat-square" alt="NPM version" />
-                </a>
-            </td>
-            <td>
-                <!-- Downloads -->
-                <a href="https://npmjs.org/package/@semaphore-protocol/hardhat">
-                    <img src="https://img.shields.io/npm/dm/@semaphore-protocol/hardhat.svg?style=flat-square" alt="Downloads" />
-                </a>
-            </td>
-        </tr>
-    <tbody>
-
-</table>
-
-## 🛠 Install
-
-Clone this repository:
-
-```bash
-git clone https://github.com/semaphore-protocol/semaphore.git
-```
-
-And install the dependencies:
-
-```bash
-cd semaphore && yarn
-```
-
-## 📜 Usage
-
-Copy the `.env.example` file as `.env`:
-
-```bash
-cp .env.example .env
-```
-
-And add your environment variables.
-
-### Code quality and formatting
-
-Run [ESLint](https://eslint.org/) to analyze the code and catch bugs:
-
-```bash
-yarn lint
-```
-
-Run [Prettier](https://prettier.io/) to check formatting rules:
-
-```bash
-yarn prettier
-```
-
-Or to automatically format the code:
-
-```bash
-yarn prettier:write
-```
-
-### Conventional commits
-
-Semaphore uses [conventional commits](https://www.conventionalcommits.org/en/v1.0.0/). A [command line utility](https://github.com/commitizen/cz-cli) to commit using the correct syntax can be used by running:
-
-```bash
-yarn commit
-```
-
-It will also automatically check that the modified files comply with ESLint and Prettier rules.
-
-### Snark artifacts
-
-Download the Semaphore snark artifacts needed to generate and verify proofs:
-
-```bash
-yarn download:snark-artifacts
-```
-
-### Testing
-
-Run [Jest](https://jestjs.io/) to test the JS libraries:
-
-```bash
-yarn test:libraries
-```
-
-Run [Mocha](https://mochajs.org/) to test the contracts:
-
-```bash
-yarn test:contracts
-```
-
-Or test everything with:
-
-```bash
-yarn test
-```
-
-### Build libraries & compile contracts
-
-Run [Rollup](https://www.rollupjs.org) to build all the packages:
-
-```bash
-yarn build:libraries
-```
-
-Compile the smart contracts with [Hardhat](https://hardhat.org/):
-
-```bash
-yarn compile:contracts
-```
-
-### Documentation (JS libraries)
-
-Run [TypeDoc](https://typedoc.org/) to generate a documentation website for each package:
-
-```bash
-yarn docs
-```
-
-The output will be placed on the `docs` folder.
+Join the [Telegram group](https://t.me/joinchat/B-PQx1U3GtAh--Z4Fwo56A) to discuss.

babel.config.json

@@ -1,3 +0,0 @@
-{
-    "presets": [["@babel/preset-env", { "targets": { "node": "current" } }], "@babel/preset-typescript"]
-}

circuits/circom/blake2s/blake2s.circom

@@ -0,0 +1,392 @@
+// based on https://github.com/zcash/librustzcash/blob/master/sapling-crypto/src/circuit/blake2s.rs
+
+include "uint32.circom";
+include "../../node_modules/circomlib/circuits/bitify.circom";
+include "../../node_modules/circomlib/circuits/sha256/rotate.circom";
+
+template MixingG(a, b, c, d) {
+  signal input in_v[16][32];
+  signal input x[32];
+  signal input y[32];
+
+  signal output out_v[16][32];
+
+  component v_a_add = Uint32Add(3);
+  for (var i = 0; i < 32; i++) {
+    v_a_add.nums_bits[0][i] <== in_v[a][i];
+    v_a_add.nums_bits[1][i] <== in_v[b][i];
+    v_a_add.nums_bits[2][i] <== x[i];
+  }
+
+  component v_d_a_xor = Uint32Xor();
+  for (var i = 0; i < 32; i++) {
+    v_d_a_xor.a_bits[i] <== in_v[d][i];
+    v_d_a_xor.b_bits[i] <== v_a_add.out_bits[i];
+  }
+
+  component v_d_a_rot = RotR(32, 16);
+  for (var i = 0; i < 32; i++) {
+    v_d_a_rot.in[i] <== v_d_a_xor.out_bits[i];
+  }
+
+  component v_c_add = Uint32Add(2);
+  for (var i = 0; i < 32; i++) {
+    v_c_add.nums_bits[0][i] <== in_v[c][i];
+    v_c_add.nums_bits[1][i] <== v_d_a_rot.out[i];
+  }
+
+  component v_b_c_xor = Uint32Xor();
+  for (var i = 0; i < 32; i++) {
+    v_b_c_xor.a_bits[i] <== in_v[b][i];
+    v_b_c_xor.b_bits[i] <== v_c_add.out_bits[i];
+  }
+
+  component v_b_c_rot = RotR(32, 12);
+  for (var i = 0; i < 32; i++) {
+    v_b_c_rot.in[i] <== v_b_c_xor.out_bits[i];
+  }
+
+  component v_a_add_2 = Uint32Add(3);
+  for (var i = 0; i < 32; i++) {
+    v_a_add_2.nums_bits[0][i] <== v_a_add.out_bits[i];
+    v_a_add_2.nums_bits[1][i] <== v_b_c_rot.out[i];
+    v_a_add_2.nums_bits[2][i] <== y[i];
+  }
+
+  component v_d_a_xor_2 = Uint32Xor();
+  for (var i = 0; i < 32; i++) {
+    v_d_a_xor_2.a_bits[i] <== v_d_a_rot.out[i];
+    v_d_a_xor_2.b_bits[i] <== v_a_add_2.out_bits[i];
+  }
+
+  component v_d_a_rot_2 = RotR(32, 8);
+  for (var i = 0; i < 32; i++) {
+    v_d_a_rot_2.in[i] <== v_d_a_xor_2.out_bits[i];
+  }
+
+  component v_c_add_2 = Uint32Add(2);
+  for (var i = 0; i < 32; i++) {
+    v_c_add_2.nums_bits[0][i] <== v_c_add.out_bits[i];
+    v_c_add_2.nums_bits[1][i] <== v_d_a_rot_2.out[i];
+  }
+
+  component v_b_c_xor_2 = Uint32Xor();
+  for (var i = 0; i < 32; i++) {
+    v_b_c_xor_2.a_bits[i] <== v_b_c_rot.out[i];
+    v_b_c_xor_2.b_bits[i] <== v_c_add_2.out_bits[i];
+  }
+
+  component v_b_c_rot_2 = RotR(32, 7);
+  for (var i = 0; i < 32; i++) {
+    v_b_c_rot_2.in[i] <== v_b_c_xor_2.out_bits[i];
+  }
+
+  for (var i = 0; i < 16; i++) {
+    for (var j = 0; j < 32; j++) {
+      if (i == a) {
+        out_v[i][j] <== v_a_add_2.out_bits[j];
+      } else if (i == b) {
+        out_v[i][j] <== v_b_c_rot_2.out[j];
+      } else if (i == c) {
+        out_v[i][j] <== v_c_add_2.out_bits[j];
+      } else if (i == d) {
+        out_v[i][j] <== v_d_a_rot_2.out[j];
+      } else {
+        out_v[i][j] <== in_v[i][j];
+      }
+    }
+  }
+}
+
+template Blake2sCompression(t, f) {
+  signal input in_h[8][32];
+  signal input in_m[16][32];
+
+  signal output out_h[8][32];
+
+  var v_consts = [
+    0x6A09E667, 0xBB67AE85, 0x3C6EF372, 0xA54FF53A, 0x510E527F, 0x9B05688C, 0x1F83D9AB, 0x5BE0CD19
+  ];
+  signal v_h[16][32];
+
+  for (var i = 0; i < 16; i++) {
+    if (i < 8) {
+      for (var j = 0; j < 32; j++) {
+        v_h[i][j] <== in_h[i][j];
+      }
+    } else {
+      for (var j = 0; j < 32; j++) {
+        v_h[i][j] <== (v_consts[i - 8] >> j) & 1;
+      }
+    }
+  }
+
+  signal v_pass_1[16][32];
+  component v_12_xor = Uint32Xor();
+  component v_13_xor = Uint32Xor();
+  component v_14_xor = Uint32Xor();
+
+  for (var i = 0; i < 16; i++) {
+    if (i == 12) {
+      for (var j = 0; j < 32; j++) {
+        v_12_xor.a_bits[j] <== v_h[i][j];
+        v_12_xor.b_bits[j] <== (t >> j) & 1;
+      }
+      for (var j = 0; j < 32; j++) {
+        v_pass_1[i][j] <== v_12_xor.out_bits[j];
+      }
+    } else if (i == 13) {
+      for (var j = 0; j < 32; j++) {
+        v_13_xor.a_bits[j] <== v_h[i][j];
+        v_13_xor.b_bits[j] <== (t >> (32 + j)) & 1;
+      }
+      for (var j = 0; j < 32; j++) {
+        v_pass_1[i][j] <== v_13_xor.out_bits[j];
+      }
+    } else if ((i == 14)) {
+      if (f == 1) {
+        for (var j = 0; j < 32; j++) {
+          v_14_xor.a_bits[j] <== v_h[i][j];
+          v_14_xor.b_bits[j] <== 1;
+        }
+        for (var j = 0; j < 32; j++) {
+          v_pass_1[i][j] <== v_14_xor.out_bits[j];
+        }
+      } else {
+        for (var j = 0; j < 32; j++) {
+          v_14_xor.a_bits[j] <== v_h[i][j];
+          v_14_xor.b_bits[j] <== 0;
+        }
+        for (var j = 0; j < 32; j++) {
+          v_pass_1[i][j] <== v_h[i][j];
+        }
+      }
+    } else {
+      for (var j = 0; j < 32; j++) {
+        v_pass_1[i][j] <== v_h[i][j];
+      }
+    }
+  }
+
+  var sigma = [
+    [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15],
+    [14, 10, 4, 8, 9, 15, 13, 6, 1, 12, 0, 2, 11, 7, 5, 3],
+    [11, 8, 12, 0, 5, 2, 15, 13, 10, 14, 3, 6, 7, 1, 9, 4],
+    [7, 9, 3, 1, 13, 12, 11, 14, 2, 6, 5, 10, 4, 0, 15, 8],
+    [9, 0, 5, 7, 2, 4, 10, 15, 14, 1, 11, 12, 6, 8, 3, 13],
+    [2, 12, 6, 10, 0, 11, 8, 3, 4, 13, 7, 5, 15, 14, 1, 9],
+    [12, 5, 1, 15, 14, 13, 4, 10, 0, 7, 6, 3, 9, 2, 8, 11],
+    [13, 11, 7, 14, 12, 1, 3, 9, 5, 0, 15, 4, 8, 6, 2, 10],
+    [6, 15, 14, 9, 11, 3, 0, 8, 12, 2, 13, 7, 1, 4, 10, 5],
+    [10, 2, 8, 4, 7, 6, 1, 5, 15, 11, 9, 14, 3, 12, 13, 0]
+  ];
+
+  component mixing_g[10][8];
+  var s;
+  for (var i = 0; i < 10; i++) {
+    s = sigma[i];
+    mixing_g[i][0] = MixingG(0, 4, 8, 12);
+    for (var j = 0; j < 16; j++) {
+      for (var k = 0; k < 32; k++) {
+        if (i == 0) {
+          mixing_g[i][0].in_v[j][k] <== v_pass_1[j][k];
+        } else {
+          mixing_g[i][0].in_v[j][k] <== mixing_g[i - 1][7].out_v[j][k];
+        }
+      }
+    }
+
+    for (var k = 0; k < 32; k++) {
+      mixing_g[i][0].x[k] <== in_m[s[0]][k];
+      mixing_g[i][0].y[k] <== in_m[s[1]][k];
+    }
+
+
+    mixing_g[i][1] = MixingG(1, 5, 9, 13);
+    for (var k = 0; k < 32; k++) {
+      for (var j = 0; j < 16; j++) {
+        mixing_g[i][1].in_v[j][k] <== mixing_g[i][0].out_v[j][k];
+      }
+      mixing_g[i][1].x[k] <== in_m[s[2]][k];
+      mixing_g[i][1].y[k] <== in_m[s[3]][k];
+    }
+
+    mixing_g[i][2] = MixingG(2, 6, 10, 14);
+    for (var k = 0; k < 32; k++) {
+      for (var j = 0; j < 16; j++) {
+        mixing_g[i][2].in_v[j][k] <== mixing_g[i][1].out_v[j][k];
+      }
+      mixing_g[i][2].x[k] <== in_m[s[4]][k];
+      mixing_g[i][2].y[k] <== in_m[s[5]][k];
+    }
+
+    mixing_g[i][3] = MixingG(3, 7, 11, 15);
+    for (var k = 0; k < 32; k++) {
+      for (var j = 0; j < 16; j++) {
+        mixing_g[i][3].in_v[j][k] <== mixing_g[i][2].out_v[j][k];
+      }
+      mixing_g[i][3].x[k] <== in_m[s[6]][k];
+      mixing_g[i][3].y[k] <== in_m[s[7]][k];
+    }
+
+    mixing_g[i][4] = MixingG(0, 5, 10, 15);
+    for (var k = 0; k < 32; k++) {
+      for (var j = 0; j < 16; j++) {
+        mixing_g[i][4].in_v[j][k] <== mixing_g[i][3].out_v[j][k];
+      }
+      mixing_g[i][4].x[k] <== in_m[s[8]][k];
+      mixing_g[i][4].y[k] <== in_m[s[9]][k];
+    }
+
+    mixing_g[i][5] = MixingG(1, 6, 11, 12);
+    for (var k = 0; k < 32; k++) {
+      for (var j = 0; j < 16; j++) {
+        mixing_g[i][5].in_v[j][k] <== mixing_g[i][4].out_v[j][k];
+      }
+      mixing_g[i][5].x[k] <== in_m[s[10]][k];
+      mixing_g[i][5].y[k] <== in_m[s[11]][k];
+    }
+
+    mixing_g[i][6] = MixingG(2, 7, 8, 13);
+    for (var k = 0; k < 32; k++) {
+      for (var j = 0; j < 16; j++) {
+        mixing_g[i][6].in_v[j][k] <== mixing_g[i][5].out_v[j][k];
+      }
+      mixing_g[i][6].x[k] <== in_m[s[12]][k];
+      mixing_g[i][6].y[k] <== in_m[s[13]][k];
+    }
+
+    mixing_g[i][7] = MixingG(3, 4, 9, 14);
+    for (var k = 0; k < 32; k++) {
+      for (var j = 0; j < 16; j++) {
+        mixing_g[i][7].in_v[j][k] <== mixing_g[i][6].out_v[j][k];
+      }
+      mixing_g[i][7].x[k] <== in_m[s[14]][k];
+      mixing_g[i][7].y[k] <== in_m[s[15]][k];
+    }
+  }
+
+  component h_xor_1[8];
+  component h_xor_2[8];
+  for (var i = 0; i < 8; i++) {
+    h_xor_1[i] = Uint32Xor();
+    h_xor_2[i] = Uint32Xor();
+    for (var j = 0; j < 32; j++) {
+      h_xor_1[i].a_bits[j] <== in_h[i][j];
+      h_xor_1[i].b_bits[j] <== mixing_g[9][7].out_v[i][j];
+    }
+
+    for (var j = 0; j < 32; j++) {
+      h_xor_2[i].a_bits[j] <== h_xor_1[i].out_bits[j];
+      h_xor_2[i].b_bits[j] <== mixing_g[9][7].out_v[i + 8][j];
+    }
+
+    for (var j = 0; j < 32; j++) {
+      out_h[i][j] <== h_xor_2[i].out_bits[j];
+    }
+  }
+}
+
+template Blake2s(n_bits, personalization) {
+  signal input in_bits[n_bits];
+  signal output out[256];
+
+  signal h[8][32];
+  component h_from_bits[8];
+  component h6_xor;
+  component h7_xor;
+
+  var h_consts = [
+    0x6A09E667 ^ 0x01010000 ^ 32,
+    0xBB67AE85,
+    0x3C6EF372,
+    0xA54FF53A,
+    0x510E527F,
+    0x9B05688C,
+    0x1F83D9AB,
+    0x5BE0CD19
+  ];
+
+  for (var i = 0; i < 8; i++) {
+    h_from_bits[i] = Num2Bits(32);
+    h_from_bits[i].in <== h_consts[i];
+    if (i == 6) {
+      h6_xor = Uint32Xor();
+      for (var j = 0; j < 32; j++) {
+        h6_xor.a_bits[j] <== h_from_bits[i].out[j];
+        h6_xor.b_bits[j] <== (personalization >> j) & 1;
+      }
+      for (var j = 0; j < 32; j++) {
+        h[i][j] <== h6_xor.out_bits[j];
+      }
+    } else if (i == 7) {
+      h7_xor = Uint32Xor();
+      for (var j = 0; j < 32; j++) {
+        h7_xor.a_bits[j] <== h_from_bits[i].out[j];
+        h7_xor.b_bits[j] <== (personalization >> (32 + j)) & 1;
+      }
+      for (var j = 0; j < 32; j++) {
+        h[i][j] <== h7_xor.out_bits[j];
+      }
+    } else {
+      for (var j = 0; j < 32; j++) {
+        h[i][j] <== h_from_bits[i].out[j];
+      }
+    }
+  }
+
+  var n_rounded;
+  if ( (n_bits % 512) == 0) {
+    n_rounded = n_bits;
+  } else {
+    n_rounded = n_bits + (512 - (n_bits % 512));
+  }
+  var num_blocks = n_rounded / 512;
+  if (num_blocks == 0) {
+    num_blocks = 1;
+  }
+
+   var n_rounded_bytes;
+  if ( (n_bits % 8) == 0) {
+    n_rounded_bytes = n_bits;
+  } else {
+    n_rounded_bytes = n_bits + (8 - (n_bits % 8));
+  }
+
+  component compressions[num_blocks];
+  var current_bit = 0;
+  for (var i = 0; i < num_blocks; i++) {
+    if (i < (num_blocks - 1)) {
+      compressions[i] = Blake2sCompression((i + 1)*64, 0);
+    } else {
+      compressions[i] = Blake2sCompression(n_rounded_bytes/8, 1);
+    }
+    for (var j = 0; j < 32; j++) {
+      for (var k = 0; k < 8; k++) {
+        if (i == 0) {
+          compressions[i].in_h[k][j] <== h[k][j];
+        } else {
+          compressions[i].in_h[k][j] <== compressions[i - 1].out_h[k][j];
+        }
+      }
+      for (var l = 0; l < 16; l++) {
+        current_bit = 512*i + 32*l + j;
+        if (current_bit < n_bits) {
+          compressions[i].in_m[l][j] <== in_bits[current_bit];
+        } else {
+          compressions[i].in_m[l][j] <== 0;
+        }
+      }
+    }
+
+    if (i == (num_blocks - 1)) {
+      for (var j = 0; j < 8; j++) {
+        for (var k = 0; k < 4; k++) {
+          for (var l = 0; l < 8; l++) {
+            out[32*j + 8*k + l] <== compressions[num_blocks - 1].out_h[8 - 1 - j][(4 - 1 - k)*8 + l];
+          }
+        }
+      }
+    }
+  }
+}

circuits/circom/blake2s/uint32.circom

@@ -0,0 +1,30 @@
+include "../../node_modules/circomlib/circuits/binsum.circom";
+
+template Uint32Add(n) {
+  signal input nums_bits[n][32];
+  signal output out_bits[32];
+
+  component sum = BinSum(32, n);
+  var i;
+  var j;
+  for (i = 0; i < n; i++) {
+    for (j = 0; j < 32; j++) {
+      sum.in[i][j] <== nums_bits[i][j];
+    }
+  }
+
+  for (j = 0; j < 32; j++) {
+    out_bits[j] <== sum.out[j];
+  }
+}
+
+template Uint32Xor() {
+  signal input a_bits[32];
+  signal input b_bits[32];
+
+  signal output out_bits[32];
+
+  for (var i = 0; i < 32; i++) {
+    out_bits[i] <== a_bits[i] + b_bits[i] - 2*a_bits[i]*b_bits[i];
+  }
+}

circuits/circom/semaphore-base.circom

@@ -0,0 +1,258 @@
+include "../node_modules/circomlib/circuits/pedersen.circom";
+include "../node_modules/circomlib/circuits/mimcsponge.circom";
+include "../node_modules/circomlib/circuits/bitify.circom";
+include "../node_modules/circomlib/circuits/eddsamimcsponge.circom";
+include "../node_modules/circomlib/circuits/babyjub.circom";
+include "../node_modules/circomlib/circuits/mux1.circom";
+include "../node_modules/circomlib/circuits/assert.circom";
+include "./blake2s/blake2s.circom";
+
+template HashLeftRight() {
+  signal input left;
+  signal input right;
+
+  signal output hash;
+
+  component hasher = MiMCSponge(2, 1);
+  left ==> hasher.ins[0];
+  right ==> hasher.ins[1];
+  hasher.k <== 0;
+
+  hash <== hasher.outs[0];
+}
+
+template Selector() {
+  signal input input_elem;
+  signal input path_elem;
+  signal input path_index;
+
+  signal output left;
+  signal output right;
+
+  path_index * (1-path_index) === 0
+
+  component mux = MultiMux1(2);
+  mux.c[0][0] <== input_elem;
+  mux.c[0][1] <== path_elem;
+
+  mux.c[1][0] <== path_elem;
+  mux.c[1][1] <== input_elem;
+
+  mux.s <== path_index;
+
+  left <== mux.out[0];
+  right <== mux.out[1];
+}
+
+template MerkleTreeInclusionProof(n_levels) {
+    signal input identity_commitment;
+    signal input identity_path_index[n_levels];
+    signal input identity_path_elements[n_levels];
+    signal output root;
+
+    component selectors[n_levels];
+    component hashers[n_levels];
+
+    for (var i = 0; i < n_levels; i++) {
+      selectors[i] = Selector();
+      hashers[i] = HashLeftRight();
+
+      identity_path_index[i] ==> selectors[i].path_index;
+      identity_path_elements[i] ==> selectors[i].path_elem;
+
+      selectors[i].left ==> hashers[i].left;
+      selectors[i].right ==> hashers[i].right;
+    }
+
+    identity_commitment ==> selectors[0].input_elem;
+
+    for (var i = 1; i < n_levels; i++) {
+      hashers[i-1].hash ==> selectors[i].input_elem;
+    }
+
+    root <== hashers[n_levels - 1].hash;
+}
+
+template CalculateIdentityCommitment(IDENTITY_PK_SIZE_IN_BITS, NULLIFIER_TRAPDOOR_SIZE_IN_BITS) {
+  signal input identity_pk[IDENTITY_PK_SIZE_IN_BITS];
+  signal input identity_nullifier[NULLIFIER_TRAPDOOR_SIZE_IN_BITS];
+  signal input identity_trapdoor[NULLIFIER_TRAPDOOR_SIZE_IN_BITS];
+
+  signal output out;
+
+  // identity commitment is a pedersen hash of (identity_pk, identity_nullifier, identity_trapdoor), each element padded up to 256 bits
+  component identity_commitment = Pedersen(3*256);
+  for (var i = 0; i < 256; i++) {
+    if (i < IDENTITY_PK_SIZE_IN_BITS) {
+      identity_commitment.in[i] <== identity_pk[i];
+    } else {
+      identity_commitment.in[i] <== 0;
+    }
+
+    if (i < NULLIFIER_TRAPDOOR_SIZE_IN_BITS) {
+      identity_commitment.in[i + 256] <== identity_nullifier[i];
+      identity_commitment.in[i + 2*256] <== identity_trapdoor[i];
+    } else {
+      identity_commitment.in[i + 256] <== 0;
+      identity_commitment.in[i + 2*256] <== 0;
+    }
+  }
+
+  out <== identity_commitment.out[0];
+}
+
+template CalculateNullifier(NULLIFIER_TRAPDOOR_SIZE_IN_BITS, EXTERNAL_NULLIFIER_SIZE_IN_BITS, n_levels) {
+  signal input external_nullifier;
+  signal input identity_nullifier[NULLIFIER_TRAPDOOR_SIZE_IN_BITS];
+  signal input identity_path_index[n_levels];
+
+  signal output nullifiers_hash;
+
+  component external_nullifier_bits = Num2Bits(EXTERNAL_NULLIFIER_SIZE_IN_BITS);
+  external_nullifier_bits.in <== external_nullifier;
+
+  var nullifiers_hasher_bits = NULLIFIER_TRAPDOOR_SIZE_IN_BITS + EXTERNAL_NULLIFIER_SIZE_IN_BITS + n_levels;
+  if (nullifiers_hasher_bits < 512) {
+    nullifiers_hasher_bits = 512;
+  }
+  assert (nullifiers_hasher_bits <= 512);
+
+  component nullifiers_hasher = Blake2s(nullifiers_hasher_bits, 0);
+  for (var i = 0; i < NULLIFIER_TRAPDOOR_SIZE_IN_BITS; i++) {
+    nullifiers_hasher.in_bits[i] <== identity_nullifier[i];
+  }
+
+  for (var i = 0; i < EXTERNAL_NULLIFIER_SIZE_IN_BITS; i++) {
+    nullifiers_hasher.in_bits[NULLIFIER_TRAPDOOR_SIZE_IN_BITS + i] <== external_nullifier_bits.out[i];
+  }
+
+  for (var i = 0; i < n_levels; i++) {
+    nullifiers_hasher.in_bits[NULLIFIER_TRAPDOOR_SIZE_IN_BITS + EXTERNAL_NULLIFIER_SIZE_IN_BITS + i] <== identity_path_index[i];
+  }
+
+  for (var i = (NULLIFIER_TRAPDOOR_SIZE_IN_BITS + EXTERNAL_NULLIFIER_SIZE_IN_BITS + n_levels); i < nullifiers_hasher_bits; i++) {
+    nullifiers_hasher.in_bits[i] <== 0;
+  }
+
+  component nullifiers_hash_num = Bits2Num(250);
+  for (var i = 0; i < 250; i++) {
+    nullifiers_hash_num.in[i] <== nullifiers_hasher.out[i];
+  }
+
+  nullifiers_hash <== nullifiers_hash_num.out;
+}
+
+// n_levels must be < 32
+template Semaphore(n_levels) {
+    // BEGIN signals
+
+    signal input signal_hash;
+    signal input external_nullifier;
+    
+    signal private input fake_zero;
+
+    // mimc vector commitment
+    signal private input identity_pk[2];
+    signal private input identity_nullifier;
+    signal private input identity_trapdoor;
+    signal private input identity_path_elements[n_levels];
+    signal private input identity_path_index[n_levels];
+
+    // signature on (external nullifier, signal_hash) with identity_pk
+    signal private input auth_sig_r[2];
+    signal private input auth_sig_s;
+
+    // mimc hash
+    signal output root;
+    signal output nullifiers_hash;
+
+    // END signals
+
+    // BEGIN constants
+
+    var IDENTITY_PK_SIZE_IN_BITS = 254;
+    var NULLIFIER_TRAPDOOR_SIZE_IN_BITS = 248;
+    var EXTERNAL_NULLIFIER_SIZE_IN_BITS = 232;
+
+    // END constants
+
+    fake_zero === 0;
+
+    component verify_identity_pk_on_curve = BabyCheck();
+    verify_identity_pk_on_curve.x <== identity_pk[0];
+    verify_identity_pk_on_curve.y <== identity_pk[1];
+
+    component verify_auth_sig_r_on_curve = BabyCheck();
+    verify_auth_sig_r_on_curve.x <== auth_sig_r[0];
+    verify_auth_sig_r_on_curve.y <== auth_sig_r[1];
+
+    // get a prime subgroup element derived from identity_pk
+    component dbl1 = BabyDbl();
+    dbl1.x <== identity_pk[0];
+    dbl1.y <== identity_pk[1];
+    component dbl2 = BabyDbl();
+    dbl2.x <== dbl1.xout;
+    dbl2.y <== dbl1.yout;
+    component dbl3 = BabyDbl();
+    dbl3.x <== dbl2.xout;
+    dbl3.y <== dbl2.yout;
+
+    component identity_nullifier_bits = Num2Bits(NULLIFIER_TRAPDOOR_SIZE_IN_BITS);
+    identity_nullifier_bits.in <== identity_nullifier;
+
+    component identity_trapdoor_bits = Num2Bits(NULLIFIER_TRAPDOOR_SIZE_IN_BITS);
+    identity_trapdoor_bits.in <== identity_trapdoor;
+
+    component identity_pk_0_bits = Num2Bits_strict();
+    identity_pk_0_bits.in <== dbl3.xout;
+
+    // BEGIN identity commitment
+    component identity_commitment = CalculateIdentityCommitment(IDENTITY_PK_SIZE_IN_BITS, NULLIFIER_TRAPDOOR_SIZE_IN_BITS);
+    for (var i = 0; i < IDENTITY_PK_SIZE_IN_BITS; i++) {
+      identity_commitment.identity_pk[i] <== identity_pk_0_bits.out[i];
+    }
+    for (var i = 0; i < NULLIFIER_TRAPDOOR_SIZE_IN_BITS; i++) {
+      identity_commitment.identity_nullifier[i] <== identity_nullifier_bits.out[i];
+      identity_commitment.identity_trapdoor[i] <== identity_trapdoor_bits.out[i];
+    }
+    // END identity commitment
+
+    // BEGIN tree
+    component tree = MerkleTreeInclusionProof(n_levels);
+    tree.identity_commitment <== identity_commitment.out;
+    for (var i = 0; i < n_levels; i++) {
+      tree.identity_path_index[i] <== identity_path_index[i];
+      tree.identity_path_elements[i] <== identity_path_elements[i];
+    }
+    root <== tree.root;
+    // END tree
+
+    // BEGIN nullifiers
+    component nullifiers_hasher = CalculateNullifier(NULLIFIER_TRAPDOOR_SIZE_IN_BITS, EXTERNAL_NULLIFIER_SIZE_IN_BITS, n_levels);
+    nullifiers_hasher.external_nullifier <== external_nullifier;
+    for (var i = 0; i < NULLIFIER_TRAPDOOR_SIZE_IN_BITS; i++) {
+      nullifiers_hasher.identity_nullifier[i] <== identity_nullifier_bits.out[i];
+    }
+    for (var i = 0; i < n_levels; i++) {
+      nullifiers_hasher.identity_path_index[i] <== identity_path_index[i];
+    }
+    nullifiers_hash <== nullifiers_hasher.nullifiers_hash;
+    // END nullifiers
+
+    // BEGIN verify sig
+    component msg_hasher = MiMCSponge(2, 1);
+    msg_hasher.ins[0] <== external_nullifier;
+    msg_hasher.ins[1] <== signal_hash;
+    msg_hasher.k <== 0;
+
+    component sig_verifier = EdDSAMiMCSpongeVerifier();
+    (1 - fake_zero) ==> sig_verifier.enabled;
+    identity_pk[0] ==> sig_verifier.Ax;
+    identity_pk[1] ==> sig_verifier.Ay;
+    auth_sig_r[0] ==> sig_verifier.R8x;
+    auth_sig_r[1] ==> sig_verifier.R8y;
+    auth_sig_s ==> sig_verifier.S;
+    msg_hasher.outs[0] ==> sig_verifier.M;
+
+    // END verify sig
+}

circuits/circom/semaphore.circom

@@ -0,0 +1,3 @@
+include "./semaphore-base.circom";
+
+component main = Semaphore(20);

circuits/jest.config.js

@@ -0,0 +1,29 @@
+module.exports = {
+    verbose: true,
+    transform: {
+        "^.+\\.tsx?$": 'ts-jest'
+    },
+    testPathIgnorePatterns: [
+        "/build/",
+        "/node_modules/",
+    ],
+    testRegex: '/__tests__/.*\\.test\\.ts$',
+    moduleFileExtensions: [
+        'ts',
+        'tsx',
+        'js',
+        'jsx',
+        'json',
+        'node'
+    ],
+    globals: {
+        'ts-jest': {
+            diagnostics: {
+                // Do not fail on TS compilation errors
+                // https://kulshekhar.github.io/ts-jest/user/config/diagnostics#do-not-fail-on-first-error
+                warnOnly: true
+            }
+        }
+    },
+    testEnvironment: 'node'
+}

circuits/package.json

@@ -0,0 +1,24 @@
+{
+    "name": "semaphore-circuits",
+    "version": "0.0.1",
+    "description": "",
+    "main": "build/index.js",
+    "scripts": {
+        "watch": "tsc --watch",
+        "build": "tsc",
+        "test-blake2s": "NODE_ENV=local-dev jest --forceExit --testPathPattern Blake2s.test.ts Uint32.test.ts"
+    },
+    "dependencies": {},
+    "devDependencies": {
+        "@types/jest": "^24.0.20",
+        "@types/node": "^12.7.7",
+        "circom": "0.0.34",
+        "circomlib": "git+https://github.com/kobigurk/circomlib.git#4284dc1ef984a204db08864f5da530c97f9376ef",
+        "jest": "^24.9.0",
+        "module-alias": "^2.2.2",
+        "snarkjs": "https://github.com/weijiekoh/snarkjs.git#ef8bbbbe5a7d37f59cdb45d3fdf2c1dcf7dd9c7a",
+        "ts-jest": "^24.1.0",
+        "typescript": "^3.7.3",
+        "websnark": "0.0.5"
+    }
+}

circuits/scripts/build_snarks.sh

@@ -0,0 +1,58 @@
+#!/bin/bash
+#
+# semaphorejs - Zero-knowledge signaling on Ethereum
+# Copyright (C) 2019 Kobi Gurkan <kobigurk@gmail.com>
+#
+# This file is part of semaphorejs.
+#
+# semaphorejs is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# semaphorejs is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with semaphorejs.  If not, see <http://www.gnu.org/licenses/>.
+
+cd "$(dirname "$0")"
+mkdir -p ../build
+cd ../build
+
+if [ -f ./circuit.json ]; then
+    echo "circuit.json already exists. Skipping."
+else
+    echo 'Generating circuit.json'
+    export NODE_OPTIONS=--max-old-space-size=4096
+    npx circom ../circom/semaphore.circom
+fi
+
+if [ -f ./proving_key.json ]; then
+    echo "proving_key.json already exists. Skipping."
+else
+    echo 'Generating proving_key.json'
+    export NODE_OPTIONS=--max-old-space-size=4096
+    npx snarkjs setup --protocol groth
+fi
+
+if [ -f ./proving_key.bin ]; then
+    echo 'proving_key.bin already exists. Skipping.'
+else
+    echo 'Generating proving_key.bin'
+    export NODE_OPTIONS=--max-old-space-size=4096
+    node ../node_modules/websnark/tools/buildpkey.js -i ./proving_key.json -o ./proving_key.bin
+fi
+
+if [ -f ./verifier.sol ]; then
+    echo 'verifier.sol already exists. Skipping.'
+else
+    echo 'Generating verifier.sol'
+    npx snarkjs generateverifier --vk ./verification_key.json -v ./verifier.sol
+fi
+
+# Copy verifier.sol to the contracts/sol directory
+echo 'Copying verifier.sol to contracts/sol.'
+cp ./verifier.sol ../../contracts/sol/

circuits/scripts/checksum_snarks.sh

@@ -0,0 +1,12 @@
+#!/bin/bash
+
+# Used by the CircleCI process to generate a checksum of the snark files so
+# that it can cache them.
+
+cd "$(dirname "$0")"
+mkdir -p ../build
+cd ../build
+
+find ../circom -type f -exec md5sum {} \; | sort -k 2 | md5sum > ./.snark_checksum
+echo 'snark checksum:'
+cat .snark_checksum

circuits/scripts/download_snarks.sh

@@ -0,0 +1,35 @@
+#!/bin/bash
+
+cd "$(dirname "$0")"
+
+CIRCUIT_JSON="https://www.dropbox.com/s/3gzxjibqgb6ke13/circuit.json?dl=1"
+PROVING_KEY_BIN="https://www.dropbox.com/s/qjlu6v125g7jkcq/proving_key.bin?dl=1"
+VERIFICATION_KEY_JSON="https://www.dropbox.com/s/rwjwu31c7pzhsth/verification_key.json?dl=1"
+VERIFIER_SOL="https://www.dropbox.com/s/q5fjzu4zxhc0393/verifier.sol?dl=1"
+
+CIRCUIT_JSON_PATH="../build/circuit.json"
+PROVING_KEY_BIN_PATH="../build/proving_key.bin"
+VERIFICATION_KEY_PATH="../build/verification_key.json"
+VERIFIER_SOL_PATH="../build/verifier.sol"
+
+mkdir -p ../build
+
+if [ ! -f "$CIRCUIT_JSON_PATH" ]; then
+    echo "Downloading circuit.json"
+    wget --quiet $CIRCUIT_JSON -O $CIRCUIT_JSON_PATH
+fi
+
+if [ ! -f "$PROVING_KEY_BIN_PATH" ]; then
+    echo "Downloading proving_key.bin"
+    wget --quiet $PROVING_KEY_BIN -O $PROVING_KEY_BIN_PATH
+fi
+
+if [ ! -f "$VERIFICATION_KEY_PATH" ]; then
+    echo "Downloading verification_key.json"
+    wget --quiet $VERIFICATION_KEY_JSON -O $VERIFICATION_KEY_PATH
+fi
+
+if [ ! -f "$VERIFIER_SOL_PATH" ]; then
+    echo "Downloading verifier.sol"
+    wget --quiet $VERIFIER_SOL -O $VERIFIER_SOL_PATH
+fi

circuits/scripts/runTestsInCircleCi.sh

@@ -0,0 +1,6 @@
+#!/bin/bash -xe
+
+cd "$(dirname "$0")"
+cd ..
+
+npm run test-blake2s

circuits/ts/__tests__/blake2s/Blake2s.test.ts

@@ -0,0 +1,51 @@
+require('module-alias/register')
+jest.setTimeout(1000000)
+
+import * as path from 'path'
+import * as snarkjs from 'snarkjs'
+const bigInt = snarkjs.bigInt
+import * as crypto from 'crypto'
+import * as compiler from 'circom'
+
+describe('Blake2s should match test vectors', () => {
+    test('Should compile mixing_g', async () => {
+        const cirDef = await compiler(path.join(__dirname, 'mixing_g_test.circom'))
+        const circuit = new snarkjs.Circuit(cirDef)
+
+        console.log('Vars: '+circuit.nVars)
+        console.log('Constraints: '+circuit.nConstraints)
+
+    })
+
+    test('Should compile blake2s_compression', async () => {
+        const cirDef = await compiler(path.join(__dirname, 'blake2s_compression_test.circom'))
+        const circuit = new snarkjs.Circuit(cirDef)
+
+        console.log('Vars: '+circuit.nVars)
+        console.log('Constraints: '+circuit.nConstraints)
+    })
+
+    test('Should run blake2s', async () => {
+        const cirDef = await compiler(path.join(__dirname, 'blake2s_test.circom'))
+        const circuit = new snarkjs.Circuit(cirDef)
+
+        console.log('Vars: '+circuit.nVars)
+        console.log('Constraints: '+circuit.nConstraints)
+
+        const bits = '11111111'
+        const inputs = {}
+        for (let i = 0; i < bits.length; i++) {
+          inputs[`in_bits[${i}]`] = bigInt(bits[i])
+        }
+        const witness = circuit.calculateWitness(inputs)
+
+        let coeff = bigInt(1)
+        let result = bigInt(0)
+        for (let i = 0; i < 256; i++) {
+          result = result.add(bigInt(witness[circuit.getSignalIdx(`main.out[${i}]`)].toString()).mul(coeff))
+          coeff = coeff.shl(1)
+        }
+        console.log(`blake2s hash: 0x${result.toString(16)}`)
+        expect(result.toString(16)).toEqual('8a1ef126b4e286703744a80b2f414be700cc93023e7bfc8688b79b54931abd27')
+    })
+})

circuits/ts/__tests__/blake2s/Uint32.test.ts

@@ -0,0 +1,93 @@
+require('module-alias/register')
+jest.setTimeout(1000000)
+
+import * as path from 'path'
+import * as snarkjs from 'snarkjs'
+const bigInt = snarkjs.bigInt
+import * as crypto from 'crypto'
+import * as compiler from 'circom'
+
+describe("Uint32 test", () => {
+    test("Should add 5 Uint32s", async () => {
+        const cirDef = await compiler(path.join(__dirname, "uint32_add_test.circom"))
+        const circuit = new snarkjs.Circuit(cirDef)
+
+        console.log("Vars: "+circuit.nVars)
+        console.log("Constraints: "+circuit.nConstraints)
+
+        const inputs = {}
+
+        const nums = [4294967295, 4294967294, 4294967293, 4294967292, 4294967291]
+        for (let i = 0; i < nums.length; i++) {
+          let num = bigInt(nums[i])
+          //inputs[`nums_vals[${i}]`] = num
+          for (let j = 0; j < 32; j++) {
+            // this extracts the least significant bit
+            const bit = num.and(bigInt(1))
+            inputs[`nums_bits[${i}][${j}]`] = bit
+            num = num.shr(1)
+          }
+        }
+        const witness = circuit.calculateWitness(inputs)
+
+        let expected_num = nums.reduce((result, current) => {
+          if (result == bigInt(-1)) {
+            result = bigInt(current)
+          } else {
+            result = result.add(bigInt(current))
+          }
+          return result
+        }, bigInt(-1))
+        let expected_bits: number[] = []
+        for (let j = 0; j < 32; j++) {
+          const bit = expected_num.and(bigInt(1))
+          expected_bits.push(bit)
+          expected_num = expected_num.shr(1)
+        }
+
+        for (let i = 0; i < 32; i++) {
+          expect(witness[circuit.getSignalIdx(`main.out_bits[${i}]`)].toString()).toEqual(snarkjs.bigInt(expected_bits[i]).toString())
+        }
+    })
+
+    test("Should xor 2 Uint32s", async () => {
+        const cirDef = await compiler(path.join(__dirname, "uint32_xor_test.circom"))
+        const circuit = new snarkjs.Circuit(cirDef)
+
+        console.log("Vars: "+circuit.nVars)
+        console.log("Constraints: "+circuit.nConstraints)
+
+        const inputs = {}
+
+        const nums = [24959295, 4594067494]
+        for (let i = 0; i < nums.length; i++) {
+          let num = bigInt(nums[i])
+          //inputs[`nums_vals[${i}]`] = num
+          for (let j = 0; j < 32; j++) {
+            // this extracts the least significant bit
+            const bit = num.and(bigInt(1))
+            let var_name
+            if (i == 0) {
+              var_name = 'a'
+            } else {
+              var_name = 'b'
+            }
+            inputs[`${var_name}_bits[${j}]`] = bit
+            num = num.shr(1)
+          }
+        }
+        const witness = circuit.calculateWitness(inputs)
+
+        let expected_num = bigInt(nums[0] ^ nums[1])
+        let expected_bits: number[] = []
+        for (let j = 0; j < 32; j++) {
+          const bit = expected_num.and(bigInt(1))
+          expected_bits.push(bit)
+          expected_num = expected_num.shr(1)
+        }
+
+        for (let i = 0; i < 32; i++) {
+          expect(witness[circuit.getSignalIdx(`main.out_bits[${i}]`)].toString()).toEqual(snarkjs.bigInt(expected_bits[i]).toString())
+        }
+    })
+})

circuits/ts/__tests__/blake2s/blake2s_compression_test.circom

@@ -0,0 +1,3 @@
+include "../../../circom/blake2s/blake2s.circom";
+
+component main = Blake2sCompression(5, 0);

circuits/ts/__tests__/blake2s/blake2s_test.circom

@@ -0,0 +1,3 @@
+include "../../../circom/blake2s/blake2s.circom";
+
+component main = Blake2s(8, 0);

circuits/ts/__tests__/blake2s/mixing_g_test.circom

@@ -0,0 +1,21 @@
+include "../../../circom/blake2s/blake2s.circom";
+
+template MixingGTester(a, b, c, d) {
+  signal input in_v[16][32];
+  signal input x[32];
+  signal input y[32];
+
+  signal out_v[16][32];
+
+  component mixing_g = MixingG(a, b, c, d);
+  for (var i = 0; i < 32; i++) {
+    mixing_g.x[i] <== x[i];
+    mixing_g.y[i] <== y[i];
+    for (var j = 0; j < 16; j++) {
+      mixing_g.in_v[j][i] <== in_v[j][i];
+      mixing_g.out_v[j][i] <== out_v[j][i];
+    }
+  }
+}
+
+component main = MixingGTester(1, 2, 3, 4);

circuits/ts/__tests__/blake2s/uint32_add_test.circom

@@ -0,0 +1,3 @@
+include "../../../circom/blake2s/uint32.circom";
+
+component main = Uint32Add(5);

circuits/ts/__tests__/blake2s/uint32_xor_test.circom

@@ -0,0 +1,3 @@
+include "../../../circom/blake2s/uint32.circom";
+
+component main = Uint32Xor();

circuits/ts/bin2hex.ts

@@ -0,0 +1,11 @@
+const bin = process.argv[2]
+
+const buf1 = Buffer.alloc(bin.length/8)
+for (let i = 0; i < buf1.length; i++) {
+  let t = 1
+  for (let j = 0; j < 8; j++) {
+    buf1[i] |= bin[8*i + j] == '1' ? t : 0
+    t *= 2
+  }
+}
+console.log(buf1.toString('hex'))

circuits/ts/hex2bin.ts

@@ -0,0 +1,10 @@
+const buf = Buffer.from(process.argv[2], 'hex')
+let s = ''
+for (let i = 0; i < buf.length; i++) {
+  let t = 1
+  for (let j = 0; j < 8; j++) {
+    s += ((buf[i] & t) == t) ? '1' : '0'
+    t *= 2
+  }
+}
+console.log(s)

circuits/tsconfig.json

@@ -0,0 +1,9 @@
+{
+    "extends": "../tsconfig.json",
+    "compilerOptions": {
+        "outDir": "./build"
+    },
+    "include": [
+        "./ts"
+    ]
+}

config/local-dev.yaml

@@ -0,0 +1,7 @@
+---
+env: 'local-dev'
+
+chain:
+  url: "http://localhost:8545"
+  chainId: 1234
+  mnemonic: "candy maple cake sugar pudding cream honey rich smooth crumble sweet treat"

config/package-lock.json

@@ -0,0 +1,89 @@
+{
+	"name": "semaphore-config",
+	"version": "0.0.1",
+	"lockfileVersion": 1,
+	"requires": true,
+	"dependencies": {
+		"@types/node": {
+			"version": "12.12.3",
+			"resolved": "https://registry.npmjs.org/@types/node/-/node-12.12.3.tgz",
+			"integrity": "sha512-opgSsy+cEF9N8MgaVPnWVtdJ3o4mV2aMHvDq7thkQUFt0EuOHJon4rQpJfhjmNHB+ikl0Cd6WhWIErOyQ+f7tw==",
+			"dev": true
+		},
+		"argparse": {
+			"version": "1.0.10",
+			"resolved": "https://registry.npmjs.org/argparse/-/argparse-1.0.10.tgz",
+			"integrity": "sha512-o5Roy6tNG4SL/FOkCAN6RzjiakZS25RLYFrcMttJqbdd8BWrnA+fGz57iN5Pb06pvBGvl5gQ0B48dJlslXvoTg==",
+			"requires": {
+				"sprintf-js": "~1.0.2"
+			}
+		},
+		"config": {
+			"version": "3.2.4",
+			"resolved": "https://registry.npmjs.org/config/-/config-3.2.4.tgz",
+			"integrity": "sha512-H1XIGfnU1EAkfjSLn9ZvYDRx9lOezDViuzLDgiJ/lMeqjYe3q6iQfpcLt2NInckJgpAeekbNhQkmnnbdEDs9rw==",
+			"requires": {
+				"json5": "^1.0.1"
+			}
+		},
+		"esprima": {
+			"version": "4.0.1",
+			"resolved": "https://registry.npmjs.org/esprima/-/esprima-4.0.1.tgz",
+			"integrity": "sha512-eGuFFw7Upda+g4p+QHvnW0RyTX/SVeJBDM/gCtMARO0cLuT2HcEKnTPvhjV6aGeqrCB/sbNop0Kszm0jsaWU4A=="
+		},
+		"inherits": {
+			"version": "2.0.3",
+			"resolved": "https://registry.npmjs.org/inherits/-/inherits-2.0.3.tgz",
+			"integrity": "sha1-Yzwsg+PaQqUC9SRmAiSA9CCCYd4="
+		},
+		"js-yaml": {
+			"version": "3.13.1",
+			"resolved": "https://registry.npmjs.org/js-yaml/-/js-yaml-3.13.1.tgz",
+			"integrity": "sha512-YfbcO7jXDdyj0DGxYVSlSeQNHbD7XPWvrVWeVUujrQEoZzWJIRrCPoyk6kL6IAjAG2IolMK4T0hNUe0HOUs5Jw==",
+			"requires": {
+				"argparse": "^1.0.7",
+				"esprima": "^4.0.0"
+			}
+		},
+		"json5": {
+			"version": "1.0.1",
+			"resolved": "https://registry.npmjs.org/json5/-/json5-1.0.1.tgz",
+			"integrity": "sha512-aKS4WQjPenRxiQsC93MNfjx+nbF4PAdYzmd/1JIj8HYzqfbu86beTuNgXDzPknWk0n0uARlyewZo4s++ES36Ow==",
+			"requires": {
+				"minimist": "^1.2.0"
+			}
+		},
+		"minimist": {
+			"version": "1.2.0",
+			"resolved": "https://registry.npmjs.org/minimist/-/minimist-1.2.0.tgz",
+			"integrity": "sha1-o1AIsg9BOD7sH7kU9M1d95omQoQ="
+		},
+		"path": {
+			"version": "0.12.7",
+			"resolved": "https://registry.npmjs.org/path/-/path-0.12.7.tgz",
+			"integrity": "sha1-1NwqUGxM4hl+tIHr/NWzbAFAsQ8=",
+			"requires": {
+				"process": "^0.11.1",
+				"util": "^0.10.3"
+			}
+		},
+		"process": {
+			"version": "0.11.10",
+			"resolved": "https://registry.npmjs.org/process/-/process-0.11.10.tgz",
+			"integrity": "sha1-czIwDoQBYb2j5podHZGn1LwW8YI="
+		},
+		"sprintf-js": {
+			"version": "1.0.3",
+			"resolved": "https://registry.npmjs.org/sprintf-js/-/sprintf-js-1.0.3.tgz",
+			"integrity": "sha1-BOaSb2YolTVPPdAVIDYzuFcpfiw="
+		},
+		"util": {
+			"version": "0.10.4",
+			"resolved": "https://registry.npmjs.org/util/-/util-0.10.4.tgz",
+			"integrity": "sha512-0Pm9hTQ3se5ll1XihRic3FDIku70C+iHUdT/W926rSgHV5QgXsYbKZN8MSC3tJtSkhuROzvsQjAaFENRXr+19A==",
+			"requires": {
+				"inherits": "2.0.3"
+			}
+		}
+	}
+}

config/package.json

@@ -0,0 +1,17 @@
+{
+    "name": "semaphore-config",
+    "version": "0.0.1",
+    "main": "build/index.js",
+    "scripts": {
+        "watch": "tsc --watch",
+        "build": "tsc"
+    },
+    "dependencies": {
+        "config": "^3.1.0",
+        "js-yaml": "^3.13.1",
+        "path": "^0.12.7"
+    },
+    "devDependencies": {
+        "@types/node": "^12.0.10"
+    }
+}

config/ts/index.ts

@@ -0,0 +1,15 @@
+import * as path from 'path'
+
+// set NODE_CONFIG_DIR 
+
+if (!process.env.hasOwnProperty('NODE_CONFIG_DIR')) {
+    process.env.NODE_CONFIG_DIR = path.join(__dirname, '../')
+}
+
+if (!process.env.hasOwnProperty('NODE_ENV')) {
+    process.env.NODE_ENV = 'local-dev'
+}
+
+const config = require('config')
+
+export { config }

config/tsconfig.json

@@ -0,0 +1,9 @@
+{
+    "extends": "../tsconfig.json",
+    "compilerOptions": {
+        "outDir": "./build"
+    },
+    "include": [
+        "./ts"
+    ]
+}

contracts/jest.config.js

@@ -0,0 +1,32 @@
+module.exports = {
+    verbose: true,
+    transform: {
+        "^.+\\.tsx?$": 'ts-jest'
+    },
+    testPathIgnorePatterns: [
+        "/build/",
+        "/node_modules/",
+    ],
+    testRegex: '/__tests__/.*\\.test\\.ts$',
+    moduleFileExtensions: [
+        'ts',
+        'tsx',
+        'js',
+        'jsx',
+        'json',
+        'node'
+    ],
+    moduleNameMapper: {
+       "^@semaphore-contracts(.*)$": "<rootDir>./$1",
+    },
+    globals: {
+        'ts-jest': {
+            diagnostics: {
+                // Do not fail on TS compilation errors
+                // https://kulshekhar.github.io/ts-jest/user/config/diagnostics#do-not-fail-on-first-error
+                warnOnly: true
+            }
+        }
+    },
+    testEnvironment: 'node'
+}

contracts/package-lock.json.REMOVED.git-id

@@ -0,0 +1 @@
+a22dd75fdaddd98d93ccf3467f78af832dc94864

contracts/package.json

@@ -0,0 +1,39 @@
+{
+    "name": "semaphore-contracts",
+    "version": "0.0.1",
+    "description": "",
+    "main": "build/index.js",
+    "scripts": {
+        "watch": "tsc --watch",
+        "ganache": "./scripts/runGanache.sh",
+        "compileSol": "./scripts/compileSol.sh",
+        "test-semaphore": "NODE_ENV=local-dev jest --forceExit --testPathPattern Semaphore.test.ts",
+        "test-semaphore-debug": "NODE_ENV=local-dev node --inspect-brk ./node_modules/jest/bin/jest.js --testPathPattern Semaphore.test.ts",
+        "test-verifier": "NODE_ENV=local-dev jest --forceExit --testPathPattern FixedVerifier.test.ts",
+        "test-verifier-debug": "NODE_ENV=local-dev node --inspect-brk ./node_modules/jest/bin/jest.js --testPathPattern FixedVerifier.test.ts",
+        "test-mt": "NODE_ENV=local-dev jest --forceExit --testPathPattern IncrementalMerkleTree.test.ts",
+        "test-mt-debug": "NODE_ENV=local-dev node --inspect-brk ./node_modules/jest/bin/jest.js --testPathPattern IncrementalMerkleTree.test.ts",
+        "build": "tsc"
+    },
+  "_moduleAliases": {
+    "@semaphore-contracts": "."
+  },
+    "dependencies": {
+        "semaphore-config": "0.0.1",
+        "ethers": "4.0.38",
+        "circomlib": "https://github.com/kobigurk/circomlib.git#347822604996bf25f659f96ee0f02810a1f71bb0",
+        "ganache-cli": "^6.7.0"
+    },
+    "devDependencies": {
+        "@types/jest": "^24.0.20",
+        "@types/node": "^12.7.7",
+        "etherlime": "^2.2.4",
+        "etherlime-lib": "^1.1.5",
+        "jest": "^24.9.0",
+        "libsemaphore": "^1.0.14",
+        "semaphore-merkle-tree": "^1.0.12",
+        "module-alias": "^2.2.2",
+        "truffle-artifactor": "^4.0.30",
+        "ts-jest": "^24.1.0"
+    }
+}

contracts/scripts/compileSol.sh

@@ -0,0 +1,19 @@
+#!/bin/bash
+
+set -e
+
+cd "$(dirname "$0")/.."
+
+echo 'Building contracts'
+
+# Delete old files
+rm -rf ./compiled/*
+
+mkdir -p ./compiled/abis
+
+# Copy the Semaphore contracts from the submodule into solidity/
+
+npx etherlime compile --solcVersion=native --buildDirectory=compiled --workingDirectory=sol --exportAbi 
+
+# Build the MiMC contract from bytecode
+node build/buildMiMC.js

contracts/scripts/runGanache.sh

@@ -0,0 +1,23 @@
+#!/bin/bash
+
+# This mnemonic seed is well-known to the public. If you transfer any ETH to
+# addreses derived from it, expect it to be swept away.
+
+# Etherlime's ganache command works differently from ganache-cli. It
+# concatenates `--count minus 10` new accounts generated from `--mnemonic`. The
+# first 10 are predefined.
+npx etherlime ganache --mnemonic "candy maple cake sugar pudding cream honey rich smooth crumble sweet treat" --gasLimit=8800000 count=10 --networkId 1234
+
+#npx ganache-cli -a 10 -m='candy maple cake sugar pudding cream honey rich smooth crumble sweet treat' --gasLimit=8800000 --port 8545 -i 1234
+
+# ETH accounts from the 'candy maple...' mnemonic
+#0: 0x627306090abab3a6e1400e9345bc60c78a8bef57
+#1: 0xf17f52151ebef6c7334fad080c5704d77216b732
+#2: 0xc5fdf4076b8f3a5357c5e395ab970b5b54098fef
+#3: 0x821aea9a577a9b44299b9c15c88cf3087f3b5544
+#4: 0x0d1d4e623d10f9fba5db95830f7d3839406c6af2
+#5: 0x2932b7a2355d6fecc4b5c0b6bd44cc31df247a2e
+#6: 0x2191ef87e392377ec08e7c08eb105ef5448eced5
+#7: 0x0f4f2ac550a1b4e2280d04c21cea7ebd822934b5
+#8: 0x6330a553fc93768f612722bb8c2ec78ac90b3bbc
+#9: 0x5aeda56215b167893e80b4fe645ba6d5bab767de

contracts/scripts/runTestsInCircleCi.sh

@@ -0,0 +1,10 @@
+#!/bin/bash -xe
+
+cd "$(dirname "$0")"
+cd ..
+
+npm run ganache &
+sleep 3 &&
+npm run test-semaphore &&
+sleep 1 &&
+npm run test-mt

contracts/sol/IncrementalMerkleTree.sol

@@ -0,0 +1,180 @@
+/*
+ * Semaphore - Zero-knowledge signaling on Ethereum
+ * Copyright (C) 2020 Barry WhiteHat <barrywhitehat@protonmail.com>, Kobi
+ * Gurkan <kobigurk@gmail.com> and Koh Wei Jie (contact@kohweijie.com)
+ *
+ * This file is part of Semaphore.
+ *
+ * Semaphore is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * Semaphore is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Semaphore.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+pragma solidity ^0.5.0;
+
+import { SnarkConstants } from "./SnarkConstants.sol";
+import { MiMC } from "./MiMC.sol";
+
+contract IncrementalMerkleTree is SnarkConstants {
+    // The maximum tree depth
+    uint8 internal constant MAX_DEPTH = 32;
+
+    // The tree depth
+    uint8 internal treeLevels;
+
+    // The number of inserted leaves
+    uint256 internal nextLeafIndex = 0;
+
+    // The Merkle root
+    uint256 public root;
+
+    // The Merkle path to the leftmost leaf upon initialisation. It *should
+    // not* be modified after it has been set by the `initMerkleTree` function.
+    // Caching these values is essential to efficient appends.
+    uint256[MAX_DEPTH] internal zeros;
+
+    // Allows you to compute the path to the element (but it's not the path to
+    // the elements). Caching these values is essential to efficient appends.
+    uint256[MAX_DEPTH] internal filledSubtrees;
+
+    // Whether the contract has already seen a particular Merkle tree root
+    mapping (uint256 => bool) public rootHistory;
+
+    event LeafInsertion(uint256 indexed leaf, uint256 indexed leafIndex);
+
+    /*
+     * Stores the Merkle root and intermediate values (the Merkle path to the
+     * the first leaf) assuming that all leaves are set to _zeroValue.
+     * @param _treeLevels The number of levels of the tree
+     * @param _zeroValue The value to set for every leaf. Ideally, this should
+     *                   be a nothing-up-my-sleeve value, so that nobody can
+     *                   say that the deployer knows the preimage of an empty
+     *                   leaf.
+     */
+    constructor(uint8 _treeLevels, uint256 _zeroValue) internal {
+        // Limit the Merkle tree to MAX_DEPTH levels
+        require(
+            _treeLevels > 0 && _treeLevels <= MAX_DEPTH,
+            "IncrementalMerkleTree: _treeLevels must be between 0 and 33"
+        );
+        
+        /*
+           To initialise the Merkle tree, we need to calculate the Merkle root
+           assuming that each leaf is the zero value.
+
+            H(H(a,b), H(c,d))
+             /             \
+            H(a,b)        H(c,d)
+             /   \        /    \
+            a     b      c      d
+
+           `zeros` and `filledSubtrees` will come in handy later when we do
+           inserts or updates. e.g when we insert a value in index 1, we will
+           need to look up values from those arrays to recalculate the Merkle
+           root.
+         */
+        treeLevels = _treeLevels;
+
+        zeros[0] = _zeroValue;
+
+        uint256 currentZero = _zeroValue;
+        for (uint8 i = 1; i < _treeLevels; i++) {
+            uint256 hashed = hashLeftRight(currentZero, currentZero);
+            zeros[i] = hashed;
+            filledSubtrees[i] = hashed;
+            currentZero = hashed;
+        }
+
+        root = hashLeftRight(currentZero, currentZero);
+    }
+
+    /*
+     * Inserts a leaf into the Merkle tree and updates the root and filled
+     * subtrees.
+     * @param _leaf The value to insert. It must be less than the snark scalar
+     *              field or this function will throw.
+     * @return The leaf index.
+     */
+    function insertLeaf(uint256 _leaf) internal returns (uint256) {
+        require(
+            _leaf < SNARK_SCALAR_FIELD,
+            "IncrementalMerkleTree: insertLeaf argument must be < SNARK_SCALAR_FIELD"
+        );
+
+        uint256 currentIndex = nextLeafIndex;
+
+        uint256 depth = uint256(treeLevels);
+        require(currentIndex < uint256(2) ** depth, "IncrementalMerkleTree: tree is full");
+
+        uint256 currentLevelHash = _leaf;
+        uint256 left;
+        uint256 right;
+
+        for (uint8 i = 0; i < treeLevels; i++) {
+            // if current_index is 5, for instance, over the iterations it will
+            // look like this: 5, 2, 1, 0, 0, 0 ...
+
+            if (currentIndex % 2 == 0) {
+                // For later values of `i`, use the previous hash as `left`, and
+                // the (hashed) zero value for `right`
+                left = currentLevelHash;
+                right = zeros[i];
+
+                filledSubtrees[i] = currentLevelHash;
+            } else {
+                left = filledSubtrees[i];
+                right = currentLevelHash;
+            }
+
+            currentLevelHash = hashLeftRight(left, right);
+
+            // equivalent to currentIndex /= 2;
+            currentIndex >>= 1;
+        }
+
+        root = currentLevelHash;
+        rootHistory[root] = true;
+
+        uint256 n = nextLeafIndex;
+        nextLeafIndex += 1;
+
+        emit LeafInsertion(_leaf, n);
+
+        return currentIndex;
+    }
+
+    /*
+     * Concatenates and hashes two `uint256` values (left and right) using
+     * a combination of MiMCSponge and `addmod`.
+     * @param _left The first value
+     * @param _right The second value
+     * @return The uint256 hash of _left and _right
+     */
+    function hashLeftRight(uint256 _left, uint256 _right) internal pure returns (uint256) {
+
+        // Solidity documentation states:
+        // `addmod(uint x, uint y, uint k) returns (uint)`:
+        // compute (x + y) % k where the addition is performed with arbitrary
+        // precision and does not wrap around at 2**256. Assert that k != 0
+        // starting from version 0.5.0.
+
+        uint256 R = _left;
+        uint256 C = 0;
+
+        (R, C) = MiMC.MiMCSponge(R, 0);
+
+        R = addmod(R, _right, SNARK_SCALAR_FIELD);
+        (R, C) = MiMC.MiMCSponge(R, C);
+
+        return R;
+    }
+}

contracts/sol/IncrementalMerkleTreeClient.sol

@@ -0,0 +1,35 @@
+/*
+ * Semaphore - Zero-knowledge signaling on Ethereum
+ * Copyright (C) 2020 Barry WhiteHat <barrywhitehat@protonmail.com>, Kobi
+ * Gurkan <kobigurk@gmail.com> and Koh Wei Jie (contact@kohweijie.com)
+ *
+ * This file is part of Semaphore.
+ *
+ * Semaphore is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * Semaphore is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Semaphore.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+pragma solidity ^0.5.0;
+
+import { IncrementalMerkleTree } from './IncrementalMerkleTree.sol';
+
+contract IncrementalMerkleTreeClient is IncrementalMerkleTree{
+    constructor(uint8 _treeLevels, uint256 _zeroValue)
+        IncrementalMerkleTree(_treeLevels, _zeroValue)
+        public {
+    }
+
+    function insertLeafAsClient(uint256 _leaf) public {
+        insertLeaf(_leaf);
+    }
+}

contracts/sol/MiMC.sol

@@ -0,0 +1,30 @@
+/*
+ * Semaphore - Zero-knowledge signaling on Ethereum
+ * Copyright (C) 2020 Barry WhiteHat <barrywhitehat@protonmail.com>, Kobi
+ * Gurkan <kobigurk@gmail.com> and Koh Wei Jie (contact@kohweijie.com)
+ *
+ * This file is part of Semaphore.
+ *
+ * Semaphore is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * Semaphore is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Semaphore.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+pragma solidity ^0.5.0;
+
+library MiMC {
+    // Note that this function could also be called "MiMCFeistel", but we name
+    // it "MiMCSponge" for consistency.
+    function MiMCSponge(uint256 in_xL, uint256 in_xR) pure public 
+               returns (uint256 xL, uint256 xR);
+}
+

contracts/sol/Ownable.sol

@@ -0,0 +1,75 @@
+pragma solidity ^0.5.0;
+
+/**
+ * @dev Contract module which provides a basic access control mechanism, where
+ * there is an account (an owner) that can be granted exclusive access to
+ * specific functions.
+ *
+ * This module is used through inheritance. It will make available the modifier
+ * `onlyOwner`, which can be aplied to your functions to restrict their use to
+ * the owner.
+ */
+contract Ownable {
+    address private _owner;
+
+    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);
+
+    /**
+     * @dev Initializes the contract setting the deployer as the initial owner.
+     */
+    constructor () internal {
+        _owner = msg.sender;
+        emit OwnershipTransferred(address(0), _owner);
+    }
+
+    /**
+     * @dev Returns the address of the current owner.
+     */
+    function owner() public view returns (address) {
+        return _owner;
+    }
+
+    /**
+     * @dev Throws if called by any account other than the owner.
+     */
+    modifier onlyOwner() {
+        require(isOwner(), "Ownable: caller is not the owner");
+        _;
+    }
+
+    /**
+     * @dev Returns true if the caller is the current owner.
+     */
+    function isOwner() public view returns (bool) {
+        return msg.sender == _owner;
+    }
+
+    /**
+     * @dev Leaves the contract without owner. It will not be possible to call
+     * `onlyOwner` functions anymore. Can only be called by the current owner.
+     *
+     * > Note: Renouncing ownership will leave the contract without an owner,
+     * thereby removing any functionality that is only available to the owner.
+     */
+    function renounceOwnership() public onlyOwner {
+        emit OwnershipTransferred(_owner, address(0));
+        _owner = address(0);
+    }
+
+    /**
+     * @dev Transfers ownership of the contract to a new account (`newOwner`).
+     * Can only be called by the current owner.
+     */
+    function transferOwnership(address newOwner) public onlyOwner {
+        _transferOwnership(newOwner);
+    }
+
+    /**
+     * @dev Transfers ownership of the contract to a new account (`newOwner`).
+     */
+    function _transferOwnership(address newOwner) internal {
+        require(newOwner != address(0), "Ownable: new owner is the zero address");
+        emit OwnershipTransferred(_owner, newOwner);
+        _owner = newOwner;
+    }
+}

contracts/sol/Semaphore.sol

@@ -0,0 +1,486 @@
+/*
+ * Semaphore - Zero-knowledge signaling on Ethereum
+ * Copyright (C) 2020 Barry WhiteHat <barrywhitehat@protonmail.com>, Kobi
+ * Gurkan <kobigurk@gmail.com> and Koh Wei Jie (contact@kohweijie.com)
+ *
+ * This file is part of Semaphore.
+ *
+ * Semaphore is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * Semaphore is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Semaphore.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+pragma solidity ^0.5.0;
+
+import "./verifier.sol";
+import { IncrementalMerkleTree } from "./IncrementalMerkleTree.sol";
+import "./Ownable.sol";
+
+contract Semaphore is Verifier, IncrementalMerkleTree, Ownable {
+    // The external nullifier helps to prevent double-signalling by the same
+    // user. An external nullifier can be active or deactivated.
+
+    // Each node in the linked list
+    struct ExternalNullifierNode {
+        uint232 next;
+        bool exists;
+        bool isActive;
+    }
+
+    // We store the external nullifiers using a mapping of the form:
+    // enA => { next external nullifier; if enA exists; if enA is active }
+    // Think of it as a linked list.
+    mapping (uint232 => ExternalNullifierNode) public
+        externalNullifierLinkedList;
+
+    uint256 public numExternalNullifiers = 0;
+    
+    // First and last external nullifiers for linked list enumeration
+    uint232 public firstExternalNullifier = 0;
+    uint232 public lastExternalNullifier = 0;
+
+    // Whether broadcastSignal() can only be called by the owner of this
+    // contract. This is the case as a safe default.
+    bool public isBroadcastPermissioned = true;
+
+    // Whether the contract has already seen a particular nullifier hash
+    mapping (uint256 => bool) public nullifierHashHistory;
+
+    event PermissionSet(bool indexed newPermission);
+    event ExternalNullifierAdd(uint232 indexed externalNullifier);
+    event ExternalNullifierChangeStatus(
+        uint232 indexed externalNullifier,
+        bool indexed active
+    );
+
+    // This value should be equal to
+    // 0x7d10c03d1f7884c85edee6353bd2b2ffbae9221236edde3778eac58089912bc0
+    // which you can calculate using the following ethersjs code:
+    // ethers.utils.solidityKeccak256(['bytes'], [ethers.utils.toUtf8Bytes('Semaphore')])
+    // By setting the value of unset (empty) tree leaves to this
+    // nothing-up-my-sleeve value, the authors hope to demonstrate that they do
+    // not have its preimage and therefore cannot spend funds they do not own.
+
+    uint256 public NOTHING_UP_MY_SLEEVE_ZERO = 
+        uint256(keccak256(abi.encodePacked('Semaphore'))) % SNARK_SCALAR_FIELD;
+
+    /*
+     * If broadcastSignal is permissioned, check if msg.sender is the contract
+     * owner
+     */
+    modifier onlyOwnerIfPermissioned() {
+        require(
+            !isBroadcastPermissioned || isOwner(),
+            "Semaphore: broadcast permission denied"
+        );
+
+        _;
+    }
+
+    /*
+     * @param _treeLevels The depth of the identity tree.
+     * @param _firstExternalNullifier The first identity nullifier to add.
+     */
+    constructor(uint8 _treeLevels, uint232 _firstExternalNullifier)
+        IncrementalMerkleTree(_treeLevels, NOTHING_UP_MY_SLEEVE_ZERO)
+        Ownable()
+        public {
+            addEn(_firstExternalNullifier, true);
+    }
+
+    /*
+     * Registers a new user. 
+     * @param _identity_commitment The user's identity commitment, which is the
+     *                            hash of their public key and their identity
+     *                            nullifier (a random 31-byte value). It should
+     *                            be the output of a Pedersen hash. It is the
+     *                            responsibility of the caller to verify this.
+     */
+    function insertIdentity(uint256 _identityCommitment) public onlyOwner
+    returns (uint256) {
+        // Ensure that the given identity commitment is not the zero value
+        require(
+            _identityCommitment != NOTHING_UP_MY_SLEEVE_ZERO,
+            "Semaphore: identity commitment cannot be the nothing-up-my-sleeve-value"
+        );
+
+        return insertLeaf(_identityCommitment);
+    }
+
+    /*
+     * Checks if all values within pi_a, pi_b, and pi_c of a zk-SNARK are less
+     * than the scalar field.
+     * @param _a The corresponding `a` parameter to verifier.sol's
+     *           verifyProof()
+     * @param _b The corresponding `b` parameter to verifier.sol's
+     *           verifyProof()
+     * @param _c The corresponding `c` parameter to verifier.sol's
+                 verifyProof()
+     */
+    function areAllValidFieldElements(
+        uint256[8] memory _proof
+    ) internal pure returns (bool) {
+        return 
+            _proof[0] < SNARK_SCALAR_FIELD &&
+            _proof[1] < SNARK_SCALAR_FIELD &&
+            _proof[2] < SNARK_SCALAR_FIELD &&
+            _proof[3] < SNARK_SCALAR_FIELD &&
+            _proof[4] < SNARK_SCALAR_FIELD &&
+            _proof[5] < SNARK_SCALAR_FIELD &&
+            _proof[6] < SNARK_SCALAR_FIELD &&
+            _proof[7] < SNARK_SCALAR_FIELD;
+    }
+
+    /*
+     * Produces a keccak256 hash of the given signal, shifted right by 8 bits.
+     * @param _signal The signal to hash
+     */
+    function hashSignal(bytes memory _signal) internal pure returns (uint256) {
+        return uint256(keccak256(_signal)) >> 8;
+    }
+
+    /*
+     * A convenience function which returns a uint256 array of 8 elements which
+     * comprise a Groth16 zk-SNARK proof's pi_a, pi_b, and pi_c  values.
+     * @param _a The corresponding `a` parameter to verifier.sol's
+     *           verifyProof()
+     * @param _b The corresponding `b` parameter to verifier.sol's
+     *           verifyProof()
+     * @param _c The corresponding `c` parameter to verifier.sol's
+     *           verifyProof()
+     */
+    function packProof (
+        uint256[2] memory _a,
+        uint256[2][2] memory _b,
+        uint256[2] memory _c
+    ) public pure returns (uint256[8] memory) {
+
+        return [
+            _a[0],
+            _a[1], 
+            _b[0][0],
+            _b[0][1],
+            _b[1][0],
+            _b[1][1],
+            _c[0],
+            _c[1]
+        ];
+    }
+
+    /*
+     * A convenience function which converts an array of 8 elements, generated
+     * by packProof(), into a format which verifier.sol's verifyProof()
+     * accepts.
+     * @param _proof The proof elements.
+     */
+    function unpackProof(
+        uint256[8] memory _proof
+    ) public pure returns (
+        uint256[2] memory,
+        uint256[2][2] memory,
+        uint256[2] memory
+    ) {
+
+        return (
+            [_proof[0], _proof[1]],
+            [
+                [_proof[2], _proof[3]],
+                [_proof[4], _proof[5]]
+            ],
+            [_proof[6], _proof[7]]
+        );
+    }
+
+
+    /*
+     * A convenience view function which helps operators to easily verify all
+     * inputs to broadcastSignal() using a single contract call. This helps
+     * them to save gas by detecting invalid inputs before they invoke
+     * broadcastSignal(). Note that this function does the same checks as
+     * `isValidSignalAndProof` but returns a bool instead of using require()
+     * statements.
+     * @param _signal The signal to broadcast
+     * @param _proof The proof elements.
+     * @param _root The Merkle tree root
+     * @param _nullifiersHash The nullifiers hash
+     * @param _signalHash The signal hash. This is included so as to verify in
+     *                    Solidity that the signal hash computed off-chain
+     *                    matches.
+     * @param _externalNullifier The external nullifier
+     */
+    function preBroadcastCheck (
+        bytes memory _signal,
+        uint256[8] memory _proof,
+        uint256 _root,
+        uint256 _nullifiersHash,
+        uint256 _signalHash,
+        uint232 _externalNullifier
+    ) public view returns (bool) {
+
+        uint256[4] memory publicSignals =
+            [_root, _nullifiersHash, _signalHash, _externalNullifier];
+
+        (uint256[2] memory a, uint256[2][2] memory b, uint256[2] memory c) = 
+            unpackProof(_proof);
+
+        return nullifierHashHistory[_nullifiersHash] == false &&
+            hashSignal(_signal) == _signalHash &&
+            _signalHash == hashSignal(_signal) &&
+            isExternalNullifierActive(_externalNullifier) &&
+            rootHistory[_root] &&
+            areAllValidFieldElements(_proof) &&
+            _root < SNARK_SCALAR_FIELD &&
+            _nullifiersHash < SNARK_SCALAR_FIELD &&
+            verifyProof(a, b, c, publicSignals);
+    }
+
+    /*
+     * A modifier which ensures that the signal and proof are valid.
+     * @param _signal The signal to broadcast
+     * @param _proof The proof elements.
+     * @param _root The Merkle tree root
+     * @param _nullifiersHash The nullifiers hash
+     * @param _signalHash The signal hash
+     * @param _externalNullifier The external nullifier
+     */
+    modifier isValidSignalAndProof (
+        bytes memory _signal,
+        uint256[8] memory _proof,
+        uint256 _root,
+        uint256 _nullifiersHash,
+        uint232 _externalNullifier
+    ) {
+        // Check whether each element in _proof is a valid field element. Even
+        // if verifier.sol does this check too, it is good to do so here for
+        // the sake of good protocol design.
+        require(
+            areAllValidFieldElements(_proof),
+            "Semaphore: invalid field element(s) in proof"
+        );
+
+        // Check whether the nullifier hash has been seen
+        require(
+            nullifierHashHistory[_nullifiersHash] == false,
+            "Semaphore: nullifier already seen"
+        );
+
+        // Check whether the nullifier hash is active
+        require(
+            isExternalNullifierActive(_externalNullifier),
+            "Semaphore: external nullifier not found"
+        );
+
+        // Check whether the given Merkle root has been seen previously
+        require(rootHistory[_root], "Semaphore: root not seen");
+
+        uint256 signalHash = hashSignal(_signal);
+
+        // Check whether _nullifiersHash is a valid field element.
+        require(
+            _nullifiersHash < SNARK_SCALAR_FIELD,
+            "Semaphore: the nullifiers hash must be lt the snark scalar field"
+        );
+
+        uint256[4] memory publicSignals =
+            [_root, _nullifiersHash, signalHash, _externalNullifier];
+
+        (uint256[2] memory a, uint256[2][2] memory b, uint256[2] memory c) =
+            unpackProof(_proof);
+
+        require(
+            verifyProof(a, b, c, publicSignals),
+            "Semaphore: invalid proof"
+        );
+
+        // Note that we don't need to check if signalHash is less than
+        // SNARK_SCALAR_FIELD because it always holds true due to the
+        // definition of hashSignal()
+
+        _;
+    }
+
+    /*
+     * Broadcasts the signal.
+     * @param _signal The signal to broadcast
+     * @param _proof The proof elements.
+     * @param _root The root of the Merkle tree (the 1st public signal)
+     * @param _nullifiersHash The nullifiers hash (the 2nd public signal)
+     * @param _externalNullifier The nullifiers hash (the 4th public signal)
+     */
+    function broadcastSignal(
+        bytes memory _signal,
+        uint256[8] memory _proof,
+        uint256 _root,
+        uint256 _nullifiersHash,
+        uint232 _externalNullifier
+    ) public 
+        onlyOwnerIfPermissioned
+        isValidSignalAndProof(
+            _signal, _proof, _root, _nullifiersHash, _externalNullifier
+        )
+    {
+        // Client contracts should be responsible for storing the signal and/or
+        // emitting it as an event 
+
+        // Store the nullifiers hash to prevent double-signalling
+        nullifierHashHistory[_nullifiersHash] = true;
+    }
+
+    /*
+     * A private helper function which adds an external nullifier.
+     * @param _externalNullifier The external nullifier to add.
+     * @param _isFirst Whether _externalNullifier is the first external
+     * nullifier. Only the constructor should set _isFirst to true when it
+     * calls addEn().
+     */
+    function addEn(uint232 _externalNullifier, bool isFirst) private {
+        if (isFirst) {
+            firstExternalNullifier = _externalNullifier;
+        } else {
+            // The external nullifier must not have already been set
+            require(
+                externalNullifierLinkedList[_externalNullifier].exists == false,
+                "Semaphore: external nullifier already set"
+            );
+
+            // Connect the previously added external nullifier node to this one
+            externalNullifierLinkedList[lastExternalNullifier].next =
+                _externalNullifier;
+        }
+
+        // Add a new external nullifier
+        externalNullifierLinkedList[_externalNullifier].next = 0;
+        externalNullifierLinkedList[_externalNullifier].isActive = true;
+        externalNullifierLinkedList[_externalNullifier].exists = true;
+
+        // Set the last external nullifier to this one
+        lastExternalNullifier = _externalNullifier;
+
+        numExternalNullifiers ++;
+
+        emit ExternalNullifierAdd(_externalNullifier);
+    }
+
+    /*
+     * Adds an external nullifier to the contract. This external nullifier is
+     * active once it is added. Only the owner can do this.
+     * @param _externalNullifier The new external nullifier to set.
+     */
+    function addExternalNullifier(uint232 _externalNullifier) public
+    onlyOwner {
+        addEn(_externalNullifier, false);
+    }
+
+    /*
+     * Deactivate an external nullifier. The external nullifier must already be
+     * active for this function to work. Only the owner can do this.
+     * @param _externalNullifier The new external nullifier to deactivate.
+     */
+    function deactivateExternalNullifier(uint232 _externalNullifier) public
+    onlyOwner {
+        // The external nullifier must already exist
+        require(
+            externalNullifierLinkedList[_externalNullifier].exists,
+            "Semaphore: external nullifier not found"
+        );
+
+        // The external nullifier must already be active
+        require(
+            externalNullifierLinkedList[_externalNullifier].isActive == true,
+            "Semaphore: external nullifier already deactivated"
+        );
+
+        // Deactivate the external nullifier. Note that we don't change the
+        // value of nextEn.
+        externalNullifierLinkedList[_externalNullifier].isActive = false;
+
+        emit ExternalNullifierChangeStatus(_externalNullifier, false);
+    }
+
+    /*
+     * Reactivate an external nullifier. The external nullifier must already be
+     * inactive for this function to work. Only the owner can do this.
+     * @param _externalNullifier The new external nullifier to reactivate.
+     */
+    function reactivateExternalNullifier(uint232 _externalNullifier) public
+    onlyOwner {
+        // The external nullifier must already exist
+        require(
+            externalNullifierLinkedList[_externalNullifier].exists,
+            "Semaphore: external nullifier not found"
+        );
+
+        // The external nullifier must already have been deactivated
+        require(
+            externalNullifierLinkedList[_externalNullifier].isActive == false,
+            "Semaphore: external nullifier is already active"
+        );
+
+        // Reactivate the external nullifier
+        externalNullifierLinkedList[_externalNullifier].isActive = true;
+
+        emit ExternalNullifierChangeStatus(_externalNullifier, true);
+    }
+
+    /*
+     * Returns true if and only if the specified external nullifier is active
+     * @param _externalNullifier The specified external nullifier.
+     */
+    function isExternalNullifierActive(uint232 _externalNullifier) public view
+    returns (bool) {
+        return externalNullifierLinkedList[_externalNullifier].isActive;
+    }
+
+    /*
+     * Returns the next external nullifier after the specified external
+     * nullifier in the linked list.
+     * @param _externalNullifier The specified external nullifier.
+     */
+    function getNextExternalNullifier(uint232 _externalNullifier) public view
+    returns (uint232) {
+
+        require(
+            externalNullifierLinkedList[_externalNullifier].exists,
+            "Semaphore: no such external nullifier"
+        );
+
+        uint232 n = externalNullifierLinkedList[_externalNullifier].next;
+
+        require(
+            numExternalNullifiers > 1 && externalNullifierLinkedList[n].exists,
+            "Semaphore: no external nullifier exists after the specified one"
+        );
+        
+        return n;
+    }
+
+    /*
+     * Returns the number of inserted identity commitments.
+     */
+    function getNumIdentityCommitments() public view returns (uint256) {
+        return nextLeafIndex;
+    }
+
+    /*
+     * Sets the `isBroadcastPermissioned` storage variable, which determines
+     * whether broadcastSignal can or cannot be called by only the contract
+     * owner.
+     * @param _newPermission True if the broadcastSignal can only be called by
+     *                       the contract owner; and False otherwise.
+     */
+    function setPermissioning(bool _newPermission) public onlyOwner {
+
+      isBroadcastPermissioned = _newPermission;
+
+      emit PermissionSet(_newPermission);
+    }
+}

contracts/sol/SemaphoreClient.sol

@@ -0,0 +1,106 @@
+/*
+ * Semaphore - Zero-knowledge signaling on Ethereum
+ * Copyright (C) 2020 Barry WhiteHat <barrywhitehat@protonmail.com>, Kobi
+ * Gurkan <kobigurk@gmail.com> and Koh Wei Jie (contact@kohweijie.com)
+ *
+ * This file is part of Semaphore.
+ *
+ * Semaphore is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * Semaphore is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Semaphore.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+pragma solidity ^0.5.0;
+
+import { Semaphore } from './Semaphore.sol';
+
+contract SemaphoreClient {
+    uint256[] public identityCommitments;
+
+    // A mapping of all signals broadcasted
+    mapping (uint256 => bytes) public signalIndexToSignal;
+
+    // A mapping between signal indices to external nullifiers
+    mapping (uint256 => uint256) public signalIndexToExternalNullifier;
+
+    // The next index of the `signalIndexToSignal` mapping
+    uint256 public nextSignalIndex = 0;
+
+    Semaphore public semaphore;
+
+    event SignalBroadcastByClient(uint256 indexed signalIndex);
+
+    constructor(Semaphore _semaphore) public {
+        semaphore = _semaphore;
+    }
+
+    function getIdentityCommitments() public view returns (uint256 [] memory) {
+        return identityCommitments;
+    }
+
+    function getIdentityCommitment(uint256 _index) public view returns (uint256) {
+        return identityCommitments[_index];
+    }
+
+    function insertIdentityAsClient(uint256 _leaf) public {
+        semaphore.insertIdentity(_leaf);
+        identityCommitments.push(_leaf);
+    }
+
+    function addExternalNullifier(uint232 _externalNullifier) public {
+        semaphore.addExternalNullifier(_externalNullifier);
+    }
+
+    function deactivateExternalNullifier(uint232 _externalNullifier) public {
+        semaphore.deactivateExternalNullifier(_externalNullifier);
+    }
+
+    function reactivateExternalNullifier(uint232 _externalNullifier) public {
+        semaphore.reactivateExternalNullifier(_externalNullifier);
+    }
+
+    function broadcastSignal(
+        bytes memory _signal,
+        uint256[8] memory _proof,
+        uint256 _root,
+        uint256 _nullifiersHash,
+        uint232 _externalNullifier
+    ) public {
+        uint256 signalIndex = nextSignalIndex;
+
+        // store the signal
+        signalIndexToSignal[nextSignalIndex] = _signal;
+
+        // map the the signal index to the given external nullifier
+        signalIndexToExternalNullifier[nextSignalIndex] = _externalNullifier;
+
+        // increment the signal index
+        nextSignalIndex ++;
+
+        // broadcast the signal
+        semaphore.broadcastSignal(_signal, _proof, _root, _nullifiersHash, _externalNullifier);
+
+        emit SignalBroadcastByClient(signalIndex);
+    }
+
+    /*
+     * Returns the external nullifier which a signal at _index broadcasted to
+     * @param _index The index to use to look up the signalIndexToExternalNullifier mapping
+     */
+    function getExternalNullifierBySignalIndex(uint256 _index) public view returns (uint256) {
+        return signalIndexToExternalNullifier[_index];
+    }
+
+    function setPermissioning(bool _newPermission) public {
+        semaphore.setPermissioning(_newPermission);
+    }
+}

contracts/sol/SnarkConstants.sol

@@ -0,0 +1,27 @@
+/*
+ * Semaphore - Zero-knowledge signaling on Ethereum
+ * Copyright (C) 2020 Barry WhiteHat <barrywhitehat@protonmail.com>, Kobi
+ * Gurkan <kobigurk@gmail.com> and Koh Wei Jie (contact@kohweijie.com)
+ *
+ * This file is part of Semaphore.
+ *
+ * Semaphore is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * Semaphore is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Semaphore.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+pragma solidity ^0.5.0;
+
+contract SnarkConstants {
+    // The scalar field
+    uint256 internal constant SNARK_SCALAR_FIELD = 21888242871839275222246405745257275088548364400416034343698204186575808495617;
+}

contracts/sol/verifier.sol

@@ -0,0 +1,231 @@
+// Copyright 2017 Christian Reitwiessner
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to
+// deal in the Software without restriction, including without limitation the
+// rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+// sell copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+// IN THE SOFTWARE.
+
+// 2019 OKIMS
+
+pragma solidity ^0.5.0;
+
+library Pairing {
+
+    uint256 constant PRIME_Q = 21888242871839275222246405745257275088696311157297823662689037894645226208583;
+
+    struct G1Point {
+        uint256 X;
+        uint256 Y;
+    }
+
+    // Encoding of field elements is: X[0] * z + X[1]
+    struct G2Point {
+        uint256[2] X;
+        uint256[2] Y;
+    }
+
+    /*
+     * @return The negation of p, i.e. p.plus(p.negate()) should be zero. 
+     */
+    function negate(G1Point memory p) internal pure returns (G1Point memory) {
+
+        // The prime q in the base field F_q for G1
+        if (p.X == 0 && p.Y == 0) {
+            return G1Point(0, 0);
+        } else {
+            return G1Point(p.X, PRIME_Q - (p.Y % PRIME_Q));
+        }
+    }
+
+    /*
+     * @return The sum of two points of G1
+     */
+    function plus(
+        G1Point memory p1,
+        G1Point memory p2
+    ) internal view returns (G1Point memory r) {
+
+        uint256[4] memory input;
+        input[0] = p1.X;
+        input[1] = p1.Y;
+        input[2] = p2.X;
+        input[3] = p2.Y;
+        bool success;
+
+        // solium-disable-next-line security/no-inline-assembly
+        assembly {
+            success := staticcall(sub(gas, 2000), 6, input, 0xc0, r, 0x60)
+            // Use "invalid" to make gas estimation work
+            switch success case 0 { invalid() }
+        }
+
+        require(success,"pairing-add-failed");
+    }
+
+    /*
+     * @return The product of a point on G1 and a scalar, i.e.
+     *         p == p.scalar_mul(1) and p.plus(p) == p.scalar_mul(2) for all
+     *         points p.
+     */
+    function scalar_mul(G1Point memory p, uint256 s) internal view returns (G1Point memory r) {
+
+        uint256[3] memory input;
+        input[0] = p.X;
+        input[1] = p.Y;
+        input[2] = s;
+        bool success;
+        // solium-disable-next-line security/no-inline-assembly
+        assembly {
+            success := staticcall(sub(gas, 2000), 7, input, 0x80, r, 0x60)
+            // Use "invalid" to make gas estimation work
+            switch success case 0 { invalid() }
+        }
+        require (success,"pairing-mul-failed");
+    }
+
+    /* @return The result of computing the pairing check
+     *         e(p1[0], p2[0]) *  .... * e(p1[n], p2[n]) == 1
+     *         For example,
+     *         pairing([P1(), P1().negate()], [P2(), P2()]) should return true.
+     */
+    function pairing(
+        G1Point memory a1,
+        G2Point memory a2,
+        G1Point memory b1,
+        G2Point memory b2,
+        G1Point memory c1,
+        G2Point memory c2,
+        G1Point memory d1,
+        G2Point memory d2
+    ) internal view returns (bool) {
+
+        G1Point[4] memory p1 = [a1, b1, c1, d1];
+        G2Point[4] memory p2 = [a2, b2, c2, d2];
+
+        uint256 inputSize = 24;
+        uint256[] memory input = new uint256[](inputSize);
+
+        for (uint256 i = 0; i < 4; i++) {
+            uint256 j = i * 6;
+            input[j + 0] = p1[i].X;
+            input[j + 1] = p1[i].Y;
+            input[j + 2] = p2[i].X[0];
+            input[j + 3] = p2[i].X[1];
+            input[j + 4] = p2[i].Y[0];
+            input[j + 5] = p2[i].Y[1];
+        }
+
+        uint256[1] memory out;
+        bool success;
+
+        // solium-disable-next-line security/no-inline-assembly
+        assembly {
+            success := staticcall(sub(gas, 2000), 8, add(input, 0x20), mul(inputSize, 0x20), out, 0x20)
+            // Use "invalid" to make gas estimation work
+            switch success case 0 { invalid() }
+        }
+
+        require(success,"pairing-opcode-failed");
+
+        return out[0] != 0;
+    }
+}
+
+contract Verifier {
+
+    using Pairing for *;
+
+    uint256 constant SNARK_SCALAR_FIELD = 21888242871839275222246405745257275088548364400416034343698204186575808495617;
+    uint256 constant PRIME_Q = 21888242871839275222246405745257275088696311157297823662689037894645226208583;
+
+    struct VerifyingKey {
+        Pairing.G1Point alfa1;
+        Pairing.G2Point beta2;
+        Pairing.G2Point gamma2;
+        Pairing.G2Point delta2;
+        Pairing.G1Point[5] IC;
+    }
+
+    struct Proof {
+        Pairing.G1Point A;
+        Pairing.G2Point B;
+        Pairing.G1Point C;
+    }
+
+    function verifyingKey() internal pure returns (VerifyingKey memory vk) {
+        vk.alfa1 = Pairing.G1Point(uint256(19412864166662840704199897530865176132379551878490098268546775855212807511623), uint256(1659653118858063231936623514142744009632862245288902525823221677276210935161));
+        vk.beta2 = Pairing.G2Point([uint256(21642731927166283717597040076624334182856179384944638206172042877912623746964), uint256(10167148937945084930725321596284210462590725859059519349238552658864205847292)], [uint256(1224040963938177736215304045934094846196618140310043882848453181887293487598), uint256(21818148805990469610055209831928752212083869699635755409679256612234566494214)]);
+        vk.gamma2 = Pairing.G2Point([uint256(7084583264208126476050882701870582484117653569260992588151213710616665494315), uint256(21338791141815158629032141160990160038215366570564838558882493662897305673845)], [uint256(20409386432685531109985133572396335050408469502427908880430269312598850603009), uint256(21694931277671378411802527161940275869759588185961914055258162012593400433477)]);
+        vk.delta2 = Pairing.G2Point([uint256(15974226699330331350608610622797702188540365463638301508490182464179306746479), uint256(10800304862034523735970868610105048512813625407055208260881866244104890739413)], [uint256(3115757193545898321493679843214264410358333980282409841160781532582592563749), uint256(20585865237865669840907249885451244426128970908885747090346049467936130099745)]);
+        vk.IC[0] = Pairing.G1Point(uint256(15132217740731663181077706894312753465210500809816534743630331656993829080728), uint256(110196461348215931979632312103651461241391911014889357659299988542624772231));
+        vk.IC[1] = Pairing.G1Point(uint256(10128725078198782996699361178651605009720713215878609701039758932704577595075), uint256(6404467707897071196443816328081887791672216217394045289711692279719912978002));
+        vk.IC[2] = Pairing.G1Point(uint256(10522674726928807143308489533204590506138344033395366996236503798983177262637), uint256(4729387380831061502587298076566203099165040519549972799644442785786542168149));
+        vk.IC[3] = Pairing.G1Point(uint256(17764548214378097040054627843654571919160111811296549132642271073668911279441), uint256(18047600752595374913303954050610046390396466710244400595444056973195374265781));
+        vk.IC[4] = Pairing.G1Point(uint256(7483741608009854810379599415076882430339556147495509532415486196559753628073), uint256(15133497018284592127224880003457371607602553122563204208188040273053737050972));
+
+    }
+    
+    /*
+     * @returns Whether the proof is valid given the hardcoded verifying key
+     *          above and the public inputs
+     */
+    function verifyProof(
+        uint256[2] memory a,
+        uint256[2][2] memory b,
+        uint256[2] memory c,
+        uint256[4] memory input
+    ) public view returns (bool r) {
+
+        Proof memory proof;
+        proof.A = Pairing.G1Point(a[0], a[1]);
+        proof.B = Pairing.G2Point([b[0][0], b[0][1]], [b[1][0], b[1][1]]);
+        proof.C = Pairing.G1Point(c[0], c[1]);
+
+        VerifyingKey memory vk = verifyingKey();
+
+        // Compute the linear combination vk_x
+        Pairing.G1Point memory vk_x = Pairing.G1Point(0, 0);
+
+        // Make sure that proof.A, B, and C are each less than the prime q
+        require(proof.A.X < PRIME_Q, "verifier-aX-gte-prime-q");
+        require(proof.A.Y < PRIME_Q, "verifier-aY-gte-prime-q");
+
+        require(proof.B.X[0] < PRIME_Q, "verifier-bX0-gte-prime-q");
+        require(proof.B.Y[0] < PRIME_Q, "verifier-bY0-gte-prime-q");
+
+        require(proof.B.X[1] < PRIME_Q, "verifier-bX1-gte-prime-q");
+        require(proof.B.Y[1] < PRIME_Q, "verifier-bY1-gte-prime-q");
+
+        require(proof.C.X < PRIME_Q, "verifier-cX-gte-prime-q");
+        require(proof.C.Y < PRIME_Q, "verifier-cY-gte-prime-q");
+
+        // Make sure that every input is less than the snark scalar field
+        for (uint256 i = 0; i < input.length; i++) {
+            require(input[i] < SNARK_SCALAR_FIELD,"verifier-gte-snark-scalar-field");
+            vk_x = Pairing.plus(vk_x, Pairing.scalar_mul(vk.IC[i + 1], input[i]));
+        }
+
+        vk_x = Pairing.plus(vk_x, vk.IC[0]);
+
+        return Pairing.pairing(
+            Pairing.negate(proof.A),
+            proof.B,
+            vk.alfa1,
+            vk.beta2,
+            vk_x,
+            vk.gamma2,
+            proof.C,
+            vk.delta2
+        );
+    }
+}

contracts/ts/__tests__/FixedVerifier.test.ts

@@ -0,0 +1,220 @@
+require('module-alias/register')
+jest.setTimeout(90000)
+
+const MiMC = require('@semaphore-contracts/compiled/MiMC.json')
+const Semaphore = require('@semaphore-contracts/compiled/Semaphore.json')
+const SemaphoreClient = require('@semaphore-contracts/compiled/SemaphoreClient.json')
+const hasEvent = require('etherlime/cli-commands/etherlime-test/events.js').hasEvent
+
+import {
+    SnarkBigInt,
+    genIdentity,
+    genIdentityCommitment,
+    genExternalNullifier,
+    genWitness,
+    genCircuit,
+    genProof,
+    genPublicSignals,
+    verifyProof,
+    SnarkProvingKey,
+    SnarkVerifyingKey,
+    parseVerifyingKeyJson,
+    formatForVerifierContract,
+} from 'libsemaphore'
+import * as etherlime from 'etherlime-lib'
+import { config } from 'semaphore-config'
+import * as path from 'path'
+import * as fs from 'fs'
+import * as ethers from 'ethers'
+
+const NUM_LEVELS = 20
+const FIRST_EXTERNAL_NULLIFIER = 0
+const SIGNAL = 'signal0'
+
+const genTestAccounts = (num: number, mnemonic: string) => {
+    let accounts: ethers.Wallet[] = []
+
+    for (let i=0; i<num; i++) {
+        const p = `m/44'/60'/${i}'/0/0`
+        const wallet = ethers.Wallet.fromMnemonic(mnemonic, p)
+        accounts.push(wallet)
+    }
+
+    return accounts
+}
+
+const accounts = genTestAccounts(2, config.chain.mnemonic)
+let semaphoreContract
+let semaphoreClientContract
+let mimcContract
+
+// hex representations of all inserted identity commitments
+let insertedIdentityCommitments: string[] = []
+const activeEn = genExternalNullifier(Date.now().toString())
+const inactiveEn = genExternalNullifier(Date.now().toString())
+const invalidEn = BigInt(Math.pow(2, 232)).toString()
+
+let deployer
+
+describe('Semaphore', () => {
+    beforeAll(async () => {
+        deployer = new etherlime.JSONRPCPrivateKeyDeployer(
+            accounts[0].privateKey,
+            config.get('chain.url'),
+            {
+                gasLimit: 8800000,
+                chainId: config.get('chain.chainId'),
+            },
+        )
+
+        console.log('Deploying MiMC')
+        mimcContract = await deployer.deploy(MiMC, {})
+
+        const libraries = {
+            MiMC: mimcContract.contractAddress,
+        }
+
+        console.log('Deploying Semaphore')
+        semaphoreContract = await deployer.deploy(
+            Semaphore,
+            libraries,
+            NUM_LEVELS,
+            FIRST_EXTERNAL_NULLIFIER,
+        )
+
+        console.log('Deploying Semaphore Client')
+        semaphoreClientContract = await deployer.deploy(
+            SemaphoreClient,
+            {},
+            semaphoreContract.contractAddress,
+        )
+
+        console.log('Transferring ownership of the Semaphore contract to the Semaphore Client')
+        const tx = await semaphoreContract.transferOwnership(
+            semaphoreClientContract.contractAddress,
+        )
+
+        await tx.wait()
+    })
+
+    test('insert an identity commitment', async () => {
+        const identity = genIdentity()
+        const identityCommitment: SnarkBigInt = genIdentityCommitment(identity)
+
+        const tx = await semaphoreClientContract.insertIdentityAsClient(
+            identityCommitment.toString()
+        )
+        const receipt = await tx.wait()
+        expect(receipt.status).toEqual(1)
+
+        console.log('Gas used by insertIdentityAsClient():', receipt.gasUsed.toString())
+
+        insertedIdentityCommitments.push('0x' + identityCommitment.toString(16))
+        expect(hasEvent(receipt, semaphoreContract, 'LeafInsertion')).toBeTruthy()
+    })
+
+    describe('signal broadcasts', () => {
+        // Load circuit, proving key, and verifying key
+        const circuitPath = path.join(__dirname, '../../../circuits/build/circuit.json')
+        const provingKeyPath = path.join(__dirname, '../../../circuits/build/proving_key.bin')
+        const verifyingKeyPath = path.join(__dirname, '../../../circuits/build/verification_key.json')
+
+        const cirDef = JSON.parse(fs.readFileSync(circuitPath).toString())
+        const provingKey: SnarkProvingKey = fs.readFileSync(provingKeyPath)
+        const verifyingKey: SnarkVerifyingKey = parseVerifyingKeyJson(fs.readFileSync(verifyingKeyPath).toString())
+        const circuit = genCircuit(cirDef)
+        let identity
+        let identityCommitment
+        let proof
+        let publicSignals
+        let params
+
+        beforeAll(async () => {
+            identity = genIdentity()
+            identityCommitment = genIdentityCommitment(identity)
+
+            await (await semaphoreClientContract.insertIdentityAsClient(identityCommitment.toString())).wait()
+
+            const leaves = await semaphoreClientContract.getIdentityCommitments()
+
+            const result = await genWitness(
+                SIGNAL,
+                circuit,
+                identity,
+                leaves,
+                NUM_LEVELS,
+                FIRST_EXTERNAL_NULLIFIER,
+            )
+
+            proof = await genProof(result.witness, provingKey)
+            publicSignals = genPublicSignals(result.witness, circuit)
+            params = formatForVerifierContract(proof, publicSignals)
+        })
+
+        test('the proof should be valid', async () => {
+            expect.assertions(1)
+            const isValid = verifyProof(verifyingKey, proof, publicSignals)
+            expect(isValid).toBeTruthy()
+        })
+
+        test('the pre-broadcast check should pass', async () => {
+            expect.assertions(1)
+
+            const check = await semaphoreContract.preBroadcastCheck(
+                ethers.utils.toUtf8Bytes(SIGNAL),
+                params.a,
+                params.b,
+                params.c,
+                params.input[0],
+                params.input[1],
+                params.input[2],
+                FIRST_EXTERNAL_NULLIFIER,
+            )
+            expect(check).toBeTruthy()
+        })
+
+        test('broadcastSignal with an input element above the scalar field should fail', async () => {
+            expect.assertions(1)
+            const size = BigInt('21888242871839275222246405745257275088548364400416034343698204186575808495617')
+            const oversizedInput = (BigInt(params.input[1]) + size).toString()
+            try {
+                await semaphoreClientContract.broadcastSignal(
+                    ethers.utils.toUtf8Bytes(SIGNAL),
+                    params.a,
+                    params.b,
+                    params.c,
+                    params.input[0],
+                    oversizedInput,
+                    FIRST_EXTERNAL_NULLIFIER,
+                )
+            } catch (e) {
+                expect(e.message.endsWith('verifier-gte-snark-scalar-field')).toBeTruthy()
+            }
+        })
+
+        test('broadcastSignal to active external nullifier with an account with the right permissions should work', async () => {
+            expect.assertions(4)
+            const tx = await semaphoreClientContract.broadcastSignal(
+                ethers.utils.toUtf8Bytes(SIGNAL),
+                params.a,
+                params.b,
+                params.c,
+                params.input[0],
+                params.input[1],
+                params.input[3],
+                { gasLimit: 1000000 },
+            )
+            const receipt = await tx.wait()
+            expect(receipt.status).toEqual(1)
+            console.log('Gas used by broadcastSignal():', receipt.gasUsed.toString())
+
+            const index = (await semaphoreClientContract.nextSignalIndex()) - 1
+            const signal = await semaphoreClientContract.signalIndexToSignal(index.toString())
+
+            expect(ethers.utils.toUtf8String(signal)).toEqual(SIGNAL)
+
+            expect(hasEvent(receipt, semaphoreContract, 'SignalBroadcast')).toBeTruthy()
+            expect(hasEvent(receipt, semaphoreClientContract, 'SignalBroadcastByClient')).toBeTruthy()
+        })
+    })
+})

contracts/ts/__tests__/IncrementalMerkleTree.test.ts

@@ -0,0 +1,130 @@
+require('module-alias/register')
+jest.setTimeout(90000)
+
+const MiMC = require('@semaphore-contracts/compiled/MiMC.json')
+const IncrementalMerkleTreeClient = require('@semaphore-contracts/compiled/IncrementalMerkleTreeClient.json')
+import * as etherlime from 'etherlime-lib'
+import { config } from 'semaphore-config'
+import * as ethers from 'ethers'
+import { storage, hashers, tree } from 'semaphore-merkle-tree'
+const mimcSpongeHasher = new hashers.MimcSpongeHasher()
+
+const account = ethers.Wallet.fromMnemonic(config.chain.mnemonic, `m/44'/60'/0'/0/0`)
+let deployer
+let mtContract
+let mimcContract
+import {
+    genIdentity,
+    genIdentityCommitment,
+    setupTree,
+} from 'libsemaphore'
+
+const LEVELS = 20
+let tree
+
+const ZERO_VALUE = 
+    ethers.utils.solidityKeccak256(
+        ['bytes'],
+        [ethers.utils.toUtf8Bytes('Semaphore')]
+    )
+
+describe('IncrementalMerkleTree functions should match the semaphore-merkle-tree implementation', () => {
+    let libraries
+
+    beforeAll(async () => {
+        tree = setupTree(LEVELS)
+
+        deployer = new etherlime.JSONRPCPrivateKeyDeployer(
+            account.privateKey,
+            config.get('chain.url'),
+            {
+                gasLimit: 8800000,
+                chainId: config.get('chain.chainId'),
+            },
+        )
+
+        console.log('Deploying MiMC')
+        mimcContract = await deployer.deploy(MiMC, {})
+
+        libraries = {
+            MiMC: mimcContract.contractAddress,
+        }
+    })
+
+    test('deployment', async () => {
+        console.log('Deploying IncrementalMerkleTreeClient')
+
+        mtContract = await deployer.deploy(
+            IncrementalMerkleTreeClient,
+            libraries,
+            LEVELS,
+            ZERO_VALUE,
+        )
+
+        const root = await mtContract.root()
+        const root2 = await tree.root()
+        expect(root.toString()).toEqual(root2)
+    })
+
+    test('deployment should fail if the specified number of levels is 0', async () => {
+        try {
+            await deployer.deploy(
+                IncrementalMerkleTreeClient,
+                libraries,
+                0,
+                ZERO_VALUE,
+            )
+        } catch (e) {
+            expect(e.message.endsWith('IncrementalMerkleTree: _treeLevels must be between 0 and 33')).toBeTruthy()
+        }
+    })
+
+    test('initMerkleTree should fail if the specified number of levels exceeds 32', async () => {
+        try {
+            await deployer.deploy(
+                IncrementalMerkleTreeClient,
+                libraries,
+                33,
+                ZERO_VALUE,
+            )
+        } catch (e) {
+            expect(e.message.endsWith('IncrementalMerkleTree: _treeLevels must be between 0 and 33')).toBeTruthy()
+        }
+    })
+
+    test('insertLeaf should fail if the leaf > the snark scalar field', async () => {
+        const leaf = '21888242871839275222246405745257275088548364400416034343698204186575808495618'
+        try {
+            await mtContract.insertLeafAsClient(leaf)
+        } catch (e) {
+            expect(e.message.endsWith('IncrementalMerkleTree: insertLeaf argument must be < SNARK_SCALAR_FIELD'))
+        }
+    })
+
+    test('insertLeaf (via insertLeafAsClient)', async () => {
+        const leaf = genIdentityCommitment(genIdentity()).toString()
+        const tx = await mtContract.insertLeafAsClient(leaf)
+        const receipt = await tx.wait()
+
+        console.log('Gas used by insertLeaf:', receipt.gasUsed.toString())
+        await tree.update(0, leaf)
+
+        const root = await mtContract.root()
+        const root2 = await tree.root()
+        expect(root.toString()).toEqual(root2)
+    })
+
+    test('inserting a few leaves should work', async () => {
+        for (let i = 1; i < 9; i++) {
+            const leaf = genIdentityCommitment(genIdentity()).toString()
+            const tx = await mtContract.insertLeafAsClient(leaf)
+            const receipt = await tx.wait()
+
+            await tree.update(i, leaf)
+
+            const root = await mtContract.root()
+            const root2 = await tree.root()
+            expect(root.toString()).toEqual(root2)
+        }
+    })
+})

contracts/ts/__tests__/Semaphore.test.ts

@@ -0,0 +1,581 @@
+require('module-alias/register')
+jest.setTimeout(90000)
+
+const MiMC = require('@semaphore-contracts/compiled/MiMC.json')
+const Semaphore = require('@semaphore-contracts/compiled/Semaphore.json')
+const SemaphoreClient = require('@semaphore-contracts/compiled/SemaphoreClient.json')
+const hasEvent = require('etherlime/cli-commands/etherlime-test/events.js').hasEvent
+
+import {
+    SnarkBigInt,
+    genIdentity,
+    genIdentityCommitment,
+    genExternalNullifier,
+    genWitness,
+    genCircuit,
+    genProof,
+    genPublicSignals,
+    verifyProof,
+    SnarkProvingKey,
+    SnarkVerifyingKey,
+    parseVerifyingKeyJson,
+    genBroadcastSignalParams,
+    genSignalHash,
+} from 'libsemaphore'
+import * as etherlime from 'etherlime-lib'
+import { config } from 'semaphore-config'
+import * as path from 'path'
+import * as fs from 'fs'
+import * as ethers from 'ethers'
+
+const NUM_LEVELS = 20
+const FIRST_EXTERNAL_NULLIFIER = 0
+const SIGNAL = 'signal0'
+
+const genTestAccounts = (num: number, mnemonic: string) => {
+    let accounts: ethers.Wallet[] = []
+
+    for (let i=0; i<num; i++) {
+        const p = `m/44'/60'/${i}'/0/0`
+        const wallet = ethers.Wallet.fromMnemonic(mnemonic, p)
+        accounts.push(wallet)
+    }
+
+    return accounts
+}
+
+const accounts = genTestAccounts(2, config.chain.mnemonic)
+let semaphoreContract
+let semaphoreClientContract
+let mimcContract
+
+// hex representations of all inserted identity commitments
+let insertedIdentityCommitments: string[] = []
+const activeEn = genExternalNullifier('1111')
+const inactiveEn = genExternalNullifier('2222')
+
+let deployer
+
+describe('Semaphore', () => {
+    beforeAll(async () => {
+        deployer = new etherlime.JSONRPCPrivateKeyDeployer(
+            accounts[0].privateKey,
+            config.get('chain.url'),
+            {
+                gasLimit: 8800000,
+                chainId: config.get('chain.chainId'),
+            },
+        )
+
+        console.log('Deploying MiMC')
+        mimcContract = await deployer.deploy(MiMC, {})
+
+        const libraries = {
+            MiMC: mimcContract.contractAddress,
+        }
+
+        console.log('Deploying Semaphore')
+        semaphoreContract = await deployer.deploy(
+            Semaphore,
+            libraries,
+            NUM_LEVELS,
+            FIRST_EXTERNAL_NULLIFIER,
+        )
+
+        console.log('Deploying Semaphore Client')
+        semaphoreClientContract = await deployer.deploy(
+            SemaphoreClient,
+            {},
+            semaphoreContract.contractAddress,
+        )
+
+        console.log('Transferring ownership of the Semaphore contract to the Semaphore Client')
+        const tx = await semaphoreContract.transferOwnership(
+            semaphoreClientContract.contractAddress,
+        )
+
+        await tx.wait()
+    })
+
+    test('Semaphore belongs to the correct owner', async () => {
+        const owner = await semaphoreContract.owner()
+        expect(owner).toEqual(semaphoreClientContract.contractAddress)
+    })
+
+    test('insert an identity commitment', async () => {
+        const identity = genIdentity()
+        const identityCommitment: SnarkBigInt = genIdentityCommitment(identity)
+
+        const tx = await semaphoreClientContract.insertIdentityAsClient(
+            identityCommitment.toString()
+        )
+        const receipt = await tx.wait()
+        expect(receipt.status).toEqual(1)
+
+        const numInserted = await semaphoreContract.getNumIdentityCommitments()
+        expect(numInserted.toString()).toEqual('1')
+
+        console.log('Gas used by insertIdentityAsClient():', receipt.gasUsed.toString())
+
+        insertedIdentityCommitments.push('0x' + identityCommitment.toString(16))
+        expect(hasEvent(receipt, semaphoreContract, 'LeafInsertion')).toBeTruthy()
+    })
+
+    describe('identity insertions', () => {
+        test('should be stored in the contract and retrievable via leaves()', async () => {
+            expect.assertions(insertedIdentityCommitments.length + 1)
+
+            const leaves = await semaphoreClientContract.getIdentityCommitments()
+            expect(leaves.length).toEqual(insertedIdentityCommitments.length)
+
+            const leavesHex = leaves.map(BigInt)
+
+            for (let i = 0; i < insertedIdentityCommitments.length; i++) {
+                const containsLeaf = leavesHex.indexOf(BigInt(insertedIdentityCommitments[i])) > -1
+                expect(containsLeaf).toBeTruthy()
+            }
+        })
+
+        test('should be stored in the contract and retrievable by enumerating leaf()', async () => {
+            expect.assertions(insertedIdentityCommitments.length)
+
+            // Assumes that insertedIdentityCommitments has the same number of
+            // elements as the number of leaves
+            const idCommsBigint = insertedIdentityCommitments.map(BigInt)
+            for (let i = 0; i < insertedIdentityCommitments.length; i++) {
+                const leaf = await semaphoreClientContract.getIdentityCommitment(i)
+                const leafHex = BigInt(leaf.toHexString())
+                expect(idCommsBigint.indexOf(leafHex) > -1).toBeTruthy()
+            }
+        })
+
+        test('inserting an identity commitment of the nothing-up-my-sleeve value should fail', async () => {
+            expect.assertions(1)
+            const nothingUpMySleeve = 
+                BigInt(ethers.utils.solidityKeccak256(['bytes'], [ethers.utils.toUtf8Bytes('Semaphore')]))
+                %
+                BigInt('21888242871839275222246405745257275088548364400416034343698204186575808495617')
+
+            try {
+                await semaphoreClientContract.insertIdentityAsClient(nothingUpMySleeve.toString())
+            } catch (e) {
+                expect(e.message.endsWith('Semaphore: identity commitment cannot be the nothing-up-my-sleeve-value')).toBeTruthy()
+            }
+        })
+
+    })
+
+    describe('external nullifiers', () => {
+
+        test('when there is only 1 external nullifier, the first and last external nullifier variables should be the same', async () => {
+            expect((await semaphoreContract.numExternalNullifiers()).toNumber()).toEqual(1)
+            const firstEn = await semaphoreContract.firstExternalNullifier()
+            const lastEn = await semaphoreContract.lastExternalNullifier()
+            expect(firstEn.toString()).toEqual(lastEn.toString())
+        })
+
+        test('getNextExternalNullifier should throw if there is only 1 external nullifier', async () => {
+            expect((await semaphoreContract.numExternalNullifiers()).toNumber()).toEqual(1)
+            const firstEn = await semaphoreContract.firstExternalNullifier()
+            try {
+                await semaphoreContract.getNextExternalNullifier(firstEn)
+            } catch (e) {
+                expect(e.message.endsWith('Semaphore: no external nullifier exists after the specified one')).toBeTruthy()
+            }
+        })
+
+        test('should be able to add an external nullifier', async () => {
+            expect.assertions(4)
+            const tx = await semaphoreClientContract.addExternalNullifier(
+                activeEn,
+                { gasLimit: 200000 },
+            )
+            const receipt = await tx.wait()
+
+            expect(receipt.status).toEqual(1)
+            expect(hasEvent(receipt, semaphoreContract, 'ExternalNullifierAdd')).toBeTruthy()
+
+            // Check if isExternalNullifierActive works
+            const isActive = await semaphoreContract.isExternalNullifierActive(activeEn)
+            expect(isActive).toBeTruthy()
+
+            // Check if numExternalNullifiers() returns the correct value
+            expect((await semaphoreContract.numExternalNullifiers()).toNumber()).toEqual(2)
+        })
+
+        test('getNextExternalNullifier should throw if there is no such external nullifier', async () => {
+            try {
+                await semaphoreContract.getNextExternalNullifier('876876876876')
+            } catch (e) {
+                expect(e.message.endsWith('Semaphore: no such external nullifier')).toBeTruthy()
+            }
+        })
+
+        test('should be able to deactivate an external nullifier', async () => {
+            await (await semaphoreClientContract.addExternalNullifier(
+                inactiveEn,
+                { gasLimit: 200000 },
+            )).wait()
+            const tx = await semaphoreClientContract.deactivateExternalNullifier(
+                inactiveEn,
+                { gasLimit: 100000 },
+            )
+            const receipt = await tx.wait()
+            expect(receipt.status).toEqual(1)
+
+            expect(await semaphoreContract.isExternalNullifierActive(inactiveEn)).toBeFalsy()
+        })
+
+        test('reactivating a deactivated external nullifier and then deactivating it should work', async () => {
+            expect.assertions(3)
+
+            // inactiveEn should be inactive
+            expect(await semaphoreContract.isExternalNullifierActive(inactiveEn)).toBeFalsy()
+
+            // reactivate inactiveEn
+            let tx = await semaphoreClientContract.reactivateExternalNullifier(
+                inactiveEn,
+                { gasLimit: 100000 },
+            ) 
+            await tx.wait()
+
+            expect(await semaphoreContract.isExternalNullifierActive(inactiveEn)).toBeTruthy()
+
+            tx = await semaphoreClientContract.deactivateExternalNullifier(
+                inactiveEn,
+                { gasLimit: 100000 },
+            )
+            await tx.wait()
+
+            expect(await semaphoreContract.isExternalNullifierActive(inactiveEn)).toBeFalsy()
+        })
+
+        test('enumerating external nullifiers should work', async () => {
+            const firstEn = await semaphoreContract.firstExternalNullifier()
+            const lastEn = await semaphoreContract.lastExternalNullifier()
+
+            const externalNullifiers: BigInt[] = [ firstEn ]
+            let currentEn = firstEn
+
+            while (currentEn.toString() !== lastEn.toString()) {
+                currentEn = await semaphoreContract.getNextExternalNullifier(currentEn)
+                externalNullifiers.push(currentEn)
+            }
+
+            expect(externalNullifiers).toHaveLength(3)
+            expect(BigInt(externalNullifiers[0].toString())).toEqual(BigInt(firstEn.toString()))
+            expect(BigInt(externalNullifiers[1].toString())).toEqual(BigInt(activeEn.toString()))
+            expect(BigInt(externalNullifiers[2].toString())).toEqual(BigInt(inactiveEn.toString()))
+        })
+    })
+
+    describe('signal broadcasts', () => {
+        // Load circuit, proving key, and verifying key
+        const circuitPath = path.join(__dirname, '../../../circuits/build/circuit.json')
+        const provingKeyPath = path.join(__dirname, '../../../circuits/build/proving_key.bin')
+        const verifyingKeyPath = path.join(__dirname, '../../../circuits/build/verification_key.json')
+
+        const cirDef = JSON.parse(fs.readFileSync(circuitPath).toString())
+        const provingKey: SnarkProvingKey = fs.readFileSync(provingKeyPath)
+        const verifyingKey: SnarkVerifyingKey = parseVerifyingKeyJson(fs.readFileSync(verifyingKeyPath).toString())
+        const circuit = genCircuit(cirDef)
+        let identity
+        let identityCommitment
+        let proof
+        let publicSignals
+        let params
+
+        beforeAll(async () => {
+            identity = genIdentity()
+            identityCommitment = genIdentityCommitment(identity)
+
+            await (await semaphoreClientContract.insertIdentityAsClient(identityCommitment.toString())).wait()
+
+            const leaves = await semaphoreClientContract.getIdentityCommitments()
+
+            const result = await genWitness(
+                SIGNAL,
+                circuit,
+                identity,
+                leaves,
+                NUM_LEVELS,
+                FIRST_EXTERNAL_NULLIFIER,
+            )
+
+            proof = await genProof(result.witness, provingKey)
+            publicSignals = genPublicSignals(result.witness, circuit)
+            params = genBroadcastSignalParams(result, proof, publicSignals)
+        })
+
+        test('the proof should be valid', async () => {
+            expect.assertions(1)
+            const isValid = verifyProof(verifyingKey, proof, publicSignals)
+            expect(isValid).toBeTruthy()
+        })
+
+        test('the pre-broadcast check should pass', async () => {
+            expect.assertions(1)
+
+            const signal = ethers.utils.toUtf8Bytes(SIGNAL)
+            const check = await semaphoreContract.preBroadcastCheck(
+                signal,
+                params.proof,
+                params.root,
+                params.nullifiersHash,
+                genSignalHash(signal).toString(),
+                FIRST_EXTERNAL_NULLIFIER,
+            )
+            expect(check).toBeTruthy()
+        })
+
+        test('the pre-broadcast check with an invalid signal should fail', async () => {
+            expect.assertions(1)
+
+            const signal = ethers.utils.toUtf8Bytes(SIGNAL)
+            const check = await semaphoreContract.preBroadcastCheck(
+                '0x0',
+                params.proof,
+                params.root,
+                params.nullifiersHash,
+                genSignalHash(signal).toString(),
+                FIRST_EXTERNAL_NULLIFIER,
+            )
+            expect(check).toBeFalsy()
+        })
+
+        test('broadcastSignal with an input element above the scalar field should fail', async () => {
+            expect.assertions(1)
+            const size = BigInt('21888242871839275222246405745257275088548364400416034343698204186575808495617')
+            const oversizedInput = (BigInt(params.nullifiersHash) + size).toString()
+            try {
+                await semaphoreClientContract.broadcastSignal(
+                    ethers.utils.toUtf8Bytes(SIGNAL),
+                    params.proof,
+                    params.root,
+                    oversizedInput,
+                    FIRST_EXTERNAL_NULLIFIER,
+                )
+            } catch (e) {
+                expect(e.message.endsWith('Semaphore: the nullifiers hash must be lt the snark scalar field')).toBeTruthy()
+            }
+        })
+
+        test('broadcastSignal with an invalid proof_data should fail', async () => {
+            expect.assertions(1)
+            try {
+                await semaphoreClientContract.broadcastSignal(
+                    ethers.utils.toUtf8Bytes(SIGNAL),
+                    [
+                        "21888242871839275222246405745257275088548364400416034343698204186575808495617",
+                        "7",
+                        "7",
+                        "7",
+                        "7",
+                        "7",
+                        "7",
+                        "7",
+                    ],
+                    params.root,
+                    params.nullifiersHash,
+                    FIRST_EXTERNAL_NULLIFIER,
+                )
+            } catch (e) {
+                expect(e.message.endsWith('Semaphore: invalid field element(s) in proof')).toBeTruthy()
+            }
+        })
+
+        test('broadcastSignal with an unseen root should fail', async () => {
+            expect.assertions(1)
+            try {
+                await semaphoreClientContract.broadcastSignal(
+                    ethers.utils.toUtf8Bytes(SIGNAL),
+                    params.proof,
+                    params.nullifiersHash, // note that this is delibrately swapped
+                    params.root,
+                    FIRST_EXTERNAL_NULLIFIER,
+                )
+            } catch (e) {
+                expect(e.message.endsWith('Semaphore: root not seen')).toBeTruthy()
+            }
+        })
+
+        test('broadcastSignal by an unpermissioned user should fail', async () => {
+            expect.assertions(1)
+            try {
+                await semaphoreContract.broadcastSignal(
+                    ethers.utils.toUtf8Bytes(SIGNAL),
+                    params.proof,
+                    params.root,
+                    params.nullifiersHash,
+                    FIRST_EXTERNAL_NULLIFIER,
+                )
+            } catch (e) {
+                expect(e.message.endsWith('Semaphore: broadcast permission denied')).toBeTruthy()
+            }
+        })
+
+        test('broadcastSignal to active external nullifier with an account with the right permissions should work', async () => {
+            expect.assertions(3)
+            const tx = await semaphoreClientContract.broadcastSignal(
+                ethers.utils.toUtf8Bytes(SIGNAL),
+                params.proof,
+                params.root,
+                params.nullifiersHash,
+                FIRST_EXTERNAL_NULLIFIER,
+                //params.externalNullifier,
+                { gasLimit: 1000000 },
+            )
+            const receipt = await tx.wait()
+            expect(receipt.status).toEqual(1)
+            console.log('Gas used by broadcastSignal():', receipt.gasUsed.toString())
+
+            const index = (await semaphoreClientContract.nextSignalIndex()) - 1
+            const signal = await semaphoreClientContract.signalIndexToSignal(index.toString())
+
+            expect(ethers.utils.toUtf8String(signal)).toEqual(SIGNAL)
+
+            expect(hasEvent(receipt, semaphoreClientContract, 'SignalBroadcastByClient')).toBeTruthy()
+        })
+
+        test('double-signalling to the same external nullifier should fail', async () => {
+            expect.assertions(1)
+            const leaves = await semaphoreClientContract.getIdentityCommitments()
+            const newSignal = 'newSignal0'
+
+            const result = await genWitness(
+                newSignal,
+                circuit,
+                identity,
+                leaves,
+                NUM_LEVELS,
+                FIRST_EXTERNAL_NULLIFIER,
+            )
+
+            proof = await genProof(result.witness, provingKey)
+            publicSignals = genPublicSignals(result.witness, circuit)
+            params = genBroadcastSignalParams(result, proof, publicSignals)
+            try {
+                const tx = await semaphoreClientContract.broadcastSignal(
+                    ethers.utils.toUtf8Bytes(newSignal),
+                    params.proof,
+                    params.root,
+                    params.nullifiersHash,
+                    FIRST_EXTERNAL_NULLIFIER,
+                )
+            } catch (e) {
+                expect(e.message.endsWith('Semaphore: nullifier already seen')).toBeTruthy()
+            }
+        })
+
+        test('signalling to a different external nullifier should work', async () => {
+            expect.assertions(1)
+            const leaves = await semaphoreClientContract.getIdentityCommitments()
+            const newSignal = 'newSignal1'
+
+            const result = await genWitness(
+                newSignal,
+                circuit,
+                identity,
+                leaves,
+                NUM_LEVELS,
+                activeEn,
+            )
+
+            proof = await genProof(result.witness, provingKey)
+            publicSignals = genPublicSignals(result.witness, circuit)
+            params = genBroadcastSignalParams(result, proof, publicSignals)
+            const tx = await semaphoreClientContract.broadcastSignal(
+                ethers.utils.toUtf8Bytes(newSignal),
+                params.proof,
+                params.root,
+                params.nullifiersHash,
+                activeEn,
+                { gasLimit: 1000000 },
+            )
+            const receipt = await tx.wait()
+            expect(receipt.status).toEqual(1)
+        })
+
+        test('broadcastSignal to a deactivated external nullifier should fail', async () => {
+            expect.assertions(2)
+            expect(await semaphoreContract.isExternalNullifierActive(inactiveEn)).toBeFalsy()
+
+            identity = genIdentity()
+            identityCommitment = genIdentityCommitment(identity)
+
+            await (await semaphoreClientContract.insertIdentityAsClient(identityCommitment.toString())).wait()
+
+            const leaves = await semaphoreClientContract.getIdentityCommitments()
+
+            const result = await genWitness(
+                SIGNAL,
+                circuit,
+                identity,
+                leaves,
+                NUM_LEVELS,
+                inactiveEn,
+            )
+
+            proof = await genProof(result.witness, provingKey)
+            publicSignals = genPublicSignals(result.witness, circuit)
+            params = genBroadcastSignalParams(result, proof, publicSignals)
+
+            try {
+                const tx = await semaphoreClientContract.broadcastSignal(
+                    ethers.utils.toUtf8Bytes(SIGNAL),
+                    params.proof,
+                    params.root,
+                    params.nullifiersHash,
+                    inactiveEn,
+                )
+            } catch (e) {
+                expect(e.message.endsWith('Semaphore: external nullifier not found')).toBeTruthy()
+            }
+        })
+
+        test('setPermissioning(false) should allow anyone to broadcast a signal', async () => {
+            expect.assertions(2)
+            const leaves = await semaphoreClientContract.getIdentityCommitments()
+            const newSignal = 'newSignal2'
+
+            const result = await genWitness(
+                newSignal,
+                circuit,
+                identity,
+                leaves,
+                NUM_LEVELS,
+                activeEn,
+            )
+
+            proof = await genProof(result.witness, provingKey)
+            publicSignals = genPublicSignals(result.witness, circuit)
+            params = genBroadcastSignalParams(result, proof, publicSignals)
+            try {
+                await semaphoreContract.broadcastSignal(
+                    ethers.utils.toUtf8Bytes(newSignal),
+                    params.proof,
+                    params.root,
+                    params.nullifiersHash,
+                    activeEn,
+                    { gasLimit: 1000000 },
+                )
+            } catch (e) {
+                expect(e.message.endsWith('Semaphore: broadcast permission denied')).toBeTruthy()
+            }
+
+            await (await semaphoreClientContract.setPermissioning(false, { gasLimit: 100000 })).wait()
+
+            const tx = await semaphoreClientContract.broadcastSignal(
+                ethers.utils.toUtf8Bytes(newSignal),
+                params.proof,
+                params.root,
+                params.nullifiersHash,
+                activeEn,
+                { gasLimit: 1000000 },
+            )
+            const receipt = await tx.wait()
+            expect(receipt.status).toEqual(1)
+        })
+
+    })
+})

contracts/ts/buildMiMC.ts

@@ -0,0 +1,18 @@
+import * as Artifactor from 'truffle-artifactor'
+const mimcGenContract = require('circomlib/src/mimcsponge_gencontract.js');
+const artifactor = new Artifactor('compiled/')
+const SEED = 'mimcsponge'
+
+const buildMiMC = async () => {
+    await artifactor.save({
+        contractName: 'MiMC',
+        abi: mimcGenContract.abi,
+        unlinked_binary: mimcGenContract.createCode(SEED, 220),
+    })
+}
+
+if (require.main === module) {
+    buildMiMC()
+}
+
+export default buildMiMC

contracts/tsconfig.json

@@ -0,0 +1,9 @@
+{
+    "extends": "../tsconfig.json",
+    "compilerOptions": {
+        "outDir": "./build"
+    },
+    "include": [
+        "./ts"
+    ]
+}

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+                    <main>
+                        <h1><a class="header" href="#about" id="about">About</a></h1>
+<p><a href="https://github.com/appliedzkp/semaphore">Semaphore</a> is a zero-knowledge gadget
+which allows Ethereum users to prove their membership of a set which they had
+previously joined without revealing their original identity. At the same time,
+it allows users to signal their endorsement of an arbitrary string. It is
+designed to be a simple and generic privacy layer for Ethereum dApps. Use cases
+include private voting, whistleblowing, mixers, and anonymous authentication.
+Finally, it provides a simple built-in mechanism to prevent double-signalling
+or double-spending.</p>
+<p>This gadget comprises of smart contracts and
+<a href="https://z.cash/technology/zksnarks/">zero-knowledge</a> components which work in
+tandem. The Semaphore smart contract handles state, permissions, and proof
+verification on-chain. The zero-knowledge components work off-chain to allow
+the user to generate proofs, which allow the smart contract to update its state
+if these proofs are valid.</p>
+<p>Semaphore is designed for smart contract and dApp developers, not end users.
+Developers should abstract its features away in order to provide user-friendly
+privacy.</p>
+<p>Try a simple demo <a href="https://weijiekoh.github.io/semaphore-ui/">here</a> or read a
+high-level description of Semaphore
+<a href="https://medium.com/coinmonks/to-mixers-and-beyond-presenting-semaphore-a-privacy-gadget-built-on-ethereum-4c8b00857c9b">here</a>.</p>
+<h2><a class="header" href="#basic-features" id="basic-features">Basic features</a></h2>
+<p>In sum, Semaphore provides the ability to:</p>
+<ol>
+<li>
+<p>Register an identity in a smart contract, and then:</p>
+</li>
+<li>
+<p>Broadcast a signal:</p>
+<ul>
+<li>
+<p>Anonymously prove that their identity is in the set of registered
+identities, and at the same time:</p>
+</li>
+<li>
+<p>Publicly store an arbitrary string in the contract, if and only if that
+string is unique to the user and the contract’s current external
+nullifier, which is a unique value akin to a topic. This means that
+double-signalling the same message under the same external nullifier is
+not possible.</p>
+</li>
+</ul>
+</li>
+</ol>
+<h3><a class="header" href="#about-external-nullifiers" id="about-external-nullifiers">About external nullifiers</a></h3>
+<p>Think of an external nullifier as a voting booth where each user may only cast
+one vote. If they try to cast a second vote a the same booth, that vote is
+invalid.</p>
+<p>An external nullifier is any 29-byte value. Semaphore always starts with one
+external nullifier, which is set upon contract deployment. The owner of the
+Semaphore contract may add more external nullifiers, deactivate, or reactivate
+existing ones.</p>
+<p>The first time a particular user broadcasts a signal to an active external
+nullifier <code>n</code>, and if the user's proof of membership of the set of registered
+users is valid, the transaction will succeed. The second time she does so to
+the same <code>n</code>, however, her transaction will fail.</p>
+<p>Additionally, all signals broadcast transactions to a deactivated external
+nullifier will fail.</p>
+<p>Each client application must use the above features of Semaphore in a unique
+way to achieve its privacy goals. A mixer, for instance, would use one external
+nullifier as such:</p>
+<table><thead><tr><th>Signal</th><th>External nullifier</th></tr></thead><tbody>
+<tr><td>The hash of the recipient's address, relayer's address, and the relayer's fee</td><td>The mixer contract's address</td></tr>
+</tbody></table>
+<p>This allows anonymous withdrawals of funds (via a transaction relayer, who is
+rewarded with a fee), and prevents double-spending as there is only one
+external nullifier.</p>
+<p>An anonymous voting app would be configured differently:</p>
+<table><thead><tr><th>Signal</th><th>External nullifier</th></tr></thead><tbody>
+<tr><td>The hash of the respondent's answer</td><td>The hash of the question</td></tr>
+</tbody></table>
+<p>This allows any user to vote with an arbitary response (e.g. yes, no, or maybe)
+to any question. The user, however, can only vote once per question.</p>
+<h2><a class="header" href="#about-the-code" id="about-the-code">About the code</a></h2>
+<p>This repository contains the code for Semaphore's contracts written in
+Soliidty, and zk-SNARK circuits written in
+<a href="https://github.com/iden3/circom">circom</a>. It also contains Typescript code to
+execute tests.</p>
+<p>The code has been audited by ABDK Consulting. Their suggested security and
+efficiency fixes have been applied.</p>
+<p>A multi-party computation to produce the zk-SNARK proving and verification keys
+for Semaphore will begin in the near future.</p>
+
+                    </main>
+
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+                        <h1><a class="header" href="#contract-api" id="contract-api">Contract API</a></h1>
+<h2><a class="header" href="#constructor" id="constructor">Constructor</a></h2>
+<p><strong>Contract ABI</strong>:</p>
+<p><code>constructor(uint8 _treeLevels, uint232 _firstExternalNullifier)</code></p>
+<ul>
+<li><code>_treeLevels</code>: The depth of the identity tree.</li>
+<li><code>_firstExternalNullifier</code>: The first identity nullifier to add.</li>
+</ul>
+<p>The depth of the identity tree determines how many identity commitments may be
+added to this contract: <code>2 ^ _treeLevels</code>. Once the tree is full, further
+insertions will fail with the revert reason <code>IncrementalMerkleTree: tree is full</code>.</p>
+<p>The first external nullifier will be added as an external nullifier to the
+contract, and this external nullifier will be active once the deployment
+completes.</p>
+<h2><a class="header" href="#add-deactivate-or-reactivate-external-nullifiiers" id="add-deactivate-or-reactivate-external-nullifiiers">Add, deactivate, or reactivate external nullifiiers</a></h2>
+<p><strong>Contract ABI</strong>:</p>
+<p><code>addExternalNullifier(uint232 _externalNullifier)</code></p>
+<p>Adds an external nullifier to the contract. Only the owner can do this.
+This external nullifier is active once it is added.</p>
+<ul>
+<li><code>_externalNullifier</code>: The new external nullifier to set.</li>
+</ul>
+<p><code>deactivateExternalNullifier(uint232 _externalNullifier)</code></p>
+<ul>
+<li><code>_externalNullifier</code>: The existing external nullifier to deactivate.</li>
+</ul>
+<p>Deactivate an external nullifier. The external nullifier must already be active
+for this function to work. Only the owner can do this.</p>
+<p><code>reactivateExternalNullifier(uint232 _externalNullifier)</code></p>
+<p>Reactivate an external nullifier. The external nullifier must already be
+inactive for this function to work. Only the owner can do this.</p>
+<ul>
+<li><code>_externalNullifier</code>: The deactivated external nullifier to reactivate.</li>
+</ul>
+<h2><a class="header" href="#insert-identities" id="insert-identities">Insert identities</a></h2>
+<p><strong>Contract ABI</strong>:</p>
+<p><code>function insertIdentity(uint256 _identityCommitment)</code></p>
+<ul>
+<li><code>_identity_commitment</code>: The user's identity commitment, which is the hash of
+their public key and their identity nullifier (a random 31-byte value). It
+should be the output of a Pedersen hash. It is the responsibility of the
+caller to verify this.</li>
+</ul>
+<p><strong>Off-chain <code>libsemaphore</code> helper functions</strong>:</p>
+<p>Use <code>genIdentity()</code> to generate an <code>Identity</code> object, and
+<code>genIdentityCommitment(identity: Identity)</code> to generate the
+<code>_identityCommitment</code> value to pass to the contract.</p>
+<p>To convert <code>identity</code> to a string and back, so that you can store it in a
+database or somewhere safe, use <code>serialiseIdentity()</code> and
+<code>unSerialiseIdentity()</code>.</p>
+<p>See the <a href="./usage.html#insert-identities">Usage section on inserting
+identities</a> for more information.</p>
+<h2><a class="header" href="#broadcast-signals" id="broadcast-signals">Broadcast signals</a></h2>
+<p><strong>Contract ABI</strong>:</p>
+<pre><code>broadcastSignal(
+    bytes memory _signal,
+    uint256[8] memory _proof,
+    uint256 _root,
+    uint256 _nullifiersHash,
+    uint232 _externalNullifier
+)
+</code></pre>
+<ul>
+<li><code>_signal</code>: the signal to broadcast.</li>
+<li><code>_proof</code>: a zk-SNARK proof (see below).</li>
+<li><code>_root</code>: The root of the identity tree, where the user's identity commitment
+is the last-inserted leaf.</li>
+<li><code>_nullifiersHash</code>: A uniquely derived hash of the external nullifier, user's
+identity nullifier, and the Merkle path index to their identity commitment.
+It ensures that a user cannot broadcast a signal with the same external
+nullifier more than once.</li>
+<li><code>_externalNullifier</code>: The external nullifier at which the signal is
+broadcast.</li>
+</ul>
+<p><strong>Off-chain <code>libsemaphore</code> helper functions</strong>:</p>
+<p>Use <code>libsemaphore</code>'s <code>genWitness()</code>, <code>genProof()</code>, <code>genPublicSignals()</code> and
+finally <code>genBroadcastSignalParams()</code> to generate the parameters to the
+contract's <code>broadcastSignal()</code> function.</p>
+<p>See the <a href="./usage.html#broadcast-signals">Usage section on broadcasting
+signals</a> for more information.</p>
+
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+                        <h1><a class="header" href="#security-audit" id="security-audit">Security audit</a></h1>
+<p>The <a href="https://ethereum.org/">Ethereum Foundation</a> and <a href="https://www.poa.network/">POA
+Network</a> commissioned <a href="https://www.abdk.consulting">ABDK
+Consulting</a> to audit the source code of Semaphore
+as well as relevant circuits in
+<a href="https://github.com/iden3/circomlib">circomlib</a>, which contains components
+which the Semaphore zk-SNARK uses.</p>
+<p>All security and performance issues have been fixed. The full audit report will
+be available soon.</p>
+
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+
+.hljs-keyword,
+.hljs-selector-tag,
+.hljs-symbol {
+  color: #ff7733;
+}
+
+.hljs-name {
+    color: #36a3d9;
+}
+
+.hljs-tag {
+    color: #00568d;
+}
+
+.hljs-emphasis {
+  font-style: italic;
+}
+
+.hljs-strong {
+  font-weight: bold;
+}
+
+.hljs-addition {
+  color: #91b362;
+}
+
+.hljs-deletion {
+  color: #d96c75;
+}

docs/book.js

@@ -0,0 +1,605 @@
+"use strict";
+
+// Fix back button cache problem
+window.onunload = function () { };
+
+// Global variable, shared between modules
+function playpen_text(playpen) {
+    let code_block = playpen.querySelector("code");
+
+    if (window.ace && code_block.classList.contains("editable")) {
+        let editor = window.ace.edit(code_block);
+        return editor.getValue();
+    } else {
+        return code_block.textContent;
+    }
+}
+
+(function codeSnippets() {
+    function fetch_with_timeout(url, options, timeout = 6000) {
+        return Promise.race([
+            fetch(url, options),
+            new Promise((_, reject) => setTimeout(() => reject(new Error('timeout')), timeout))
+        ]);
+    }
+
+    var playpens = Array.from(document.querySelectorAll(".playpen"));
+    if (playpens.length > 0) {
+        fetch_with_timeout("https://play.rust-lang.org/meta/crates", {
+            headers: {
+                'Content-Type': "application/json",
+            },
+            method: 'POST',
+            mode: 'cors',
+        })
+        .then(response => response.json())
+        .then(response => {
+            // get list of crates available in the rust playground
+            let playground_crates = response.crates.map(item => item["id"]);
+            playpens.forEach(block => handle_crate_list_update(block, playground_crates));
+        });
+    }
+
+    function handle_crate_list_update(playpen_block, playground_crates) {
+        // update the play buttons after receiving the response
+        update_play_button(playpen_block, playground_crates);
+
+        // and install on change listener to dynamically update ACE editors
+        if (window.ace) {
+            let code_block = playpen_block.querySelector("code");
+            if (code_block.classList.contains("editable")) {
+                let editor = window.ace.edit(code_block);
+                editor.addEventListener("change", function (e) {
+                    update_play_button(playpen_block, playground_crates);
+                });
+                // add Ctrl-Enter command to execute rust code
+                editor.commands.addCommand({
+                    name: "run",
+                    bindKey: {
+                        win: "Ctrl-Enter",
+                        mac: "Ctrl-Enter"
+                    },
+                    exec: _editor => run_rust_code(playpen_block)
+                });
+            }
+        }
+    }
+
+    // updates the visibility of play button based on `no_run` class and
+    // used crates vs ones available on http://play.rust-lang.org
+    function update_play_button(pre_block, playground_crates) {
+        var play_button = pre_block.querySelector(".play-button");
+
+        // skip if code is `no_run`
+        if (pre_block.querySelector('code').classList.contains("no_run")) {
+            play_button.classList.add("hidden");
+            return;
+        }
+
+        // get list of `extern crate`'s from snippet
+        var txt = playpen_text(pre_block);
+        var re = /extern\s+crate\s+([a-zA-Z_0-9]+)\s*;/g;
+        var snippet_crates = [];
+        var item;
+        while (item = re.exec(txt)) {
+            snippet_crates.push(item[1]);
+        }
+
+        // check if all used crates are available on play.rust-lang.org
+        var all_available = snippet_crates.every(function (elem) {
+            return playground_crates.indexOf(elem) > -1;
+        });
+
+        if (all_available) {
+            play_button.classList.remove("hidden");
+        } else {
+            play_button.classList.add("hidden");
+        }
+    }
+
+    function run_rust_code(code_block) {
+        var result_block = code_block.querySelector(".result");
+        if (!result_block) {
+            result_block = document.createElement('code');
+            result_block.className = 'result hljs language-bash';
+
+            code_block.append(result_block);
+        }
+
+        let text = playpen_text(code_block);
+        let classes = code_block.querySelector('code').classList;
+        let has_2018 = classes.contains("edition2018");
+        let edition = has_2018 ? "2018" : "2015";
+
+        var params = {
+            version: "stable",
+            optimize: "0",
+            code: text,
+            edition: edition
+        };
+
+        if (text.indexOf("#![feature") !== -1) {
+            params.version = "nightly";
+        }
+
+        result_block.innerText = "Running...";
+
+        fetch_with_timeout("https://play.rust-lang.org/evaluate.json", {
+            headers: {
+                'Content-Type': "application/json",
+            },
+            method: 'POST',
+            mode: 'cors',
+            body: JSON.stringify(params)
+        })
+        .then(response => response.json())
+        .then(response => result_block.innerText = response.result)
+        .catch(error => result_block.innerText = "Playground Communication: " + error.message);
+    }
+
+    // Syntax highlighting Configuration
+    hljs.configure({
+        tabReplace: '    ', // 4 spaces
+        languages: [],      // Languages used for auto-detection
+    });
+
+    if (window.ace) {
+        // language-rust class needs to be removed for editable
+        // blocks or highlightjs will capture events
+        Array
+            .from(document.querySelectorAll('code.editable'))
+            .forEach(function (block) { block.classList.remove('language-rust'); });
+
+        Array
+            .from(document.querySelectorAll('code:not(.editable)'))
+            .forEach(function (block) { hljs.highlightBlock(block); });
+    } else {
+        Array
+            .from(document.querySelectorAll('code'))
+            .forEach(function (block) { hljs.highlightBlock(block); });
+    }
+
+    // Adding the hljs class gives code blocks the color css
+    // even if highlighting doesn't apply
+    Array
+        .from(document.querySelectorAll('code'))
+        .forEach(function (block) { block.classList.add('hljs'); });
+
+    Array.from(document.querySelectorAll("code.language-rust")).forEach(function (block) {
+
+        var lines = Array.from(block.querySelectorAll('.boring'));
+        // If no lines were hidden, return
+        if (!lines.length) { return; }
+        block.classList.add("hide-boring");
+
+        var buttons = document.createElement('div');
+        buttons.className = 'buttons';
+        buttons.innerHTML = "<button class=\"fa fa-expand\" title=\"Show hidden lines\" aria-label=\"Show hidden lines\"></button>";
+
+        // add expand button
+        var pre_block = block.parentNode;
+        pre_block.insertBefore(buttons, pre_block.firstChild);
+
+        pre_block.querySelector('.buttons').addEventListener('click', function (e) {
+            if (e.target.classList.contains('fa-expand')) {
+                e.target.classList.remove('fa-expand');
+                e.target.classList.add('fa-compress');
+                e.target.title = 'Hide lines';
+                e.target.setAttribute('aria-label', e.target.title);
+
+                block.classList.remove('hide-boring');
+            } else if (e.target.classList.contains('fa-compress')) {
+                e.target.classList.remove('fa-compress');
+                e.target.classList.add('fa-expand');
+                e.target.title = 'Show hidden lines';
+                e.target.setAttribute('aria-label', e.target.title);
+
+                block.classList.add('hide-boring');
+            }
+        });
+    });
+
+    if (window.playpen_copyable) {
+        Array.from(document.querySelectorAll('pre code')).forEach(function (block) {
+            var pre_block = block.parentNode;
+            if (!pre_block.classList.contains('playpen')) {
+                var buttons = pre_block.querySelector(".buttons");
+                if (!buttons) {
+                    buttons = document.createElement('div');
+                    buttons.className = 'buttons';
+                    pre_block.insertBefore(buttons, pre_block.firstChild);
+                }
+
+                var clipButton = document.createElement('button');
+                clipButton.className = 'fa fa-copy clip-button';
+                clipButton.title = 'Copy to clipboard';
+                clipButton.setAttribute('aria-label', clipButton.title);
+                clipButton.innerHTML = '<i class=\"tooltiptext\"></i>';
+
+                buttons.insertBefore(clipButton, buttons.firstChild);
+            }
+        });
+    }
+
+    // Process playpen code blocks
+    Array.from(document.querySelectorAll(".playpen")).forEach(function (pre_block) {
+        // Add play button
+        var buttons = pre_block.querySelector(".buttons");
+        if (!buttons) {
+            buttons = document.createElement('div');
+            buttons.className = 'buttons';
+            pre_block.insertBefore(buttons, pre_block.firstChild);
+        }
+
+        var runCodeButton = document.createElement('button');
+        runCodeButton.className = 'fa fa-play play-button';
+        runCodeButton.hidden = true;
+        runCodeButton.title = 'Run this code';
+        runCodeButton.setAttribute('aria-label', runCodeButton.title);
+
+        buttons.insertBefore(runCodeButton, buttons.firstChild);
+        runCodeButton.addEventListener('click', function (e) {
+            run_rust_code(pre_block);
+        });
+
+        if (window.playpen_copyable) {
+            var copyCodeClipboardButton = document.createElement('button');
+            copyCodeClipboardButton.className = 'fa fa-copy clip-button';
+            copyCodeClipboardButton.innerHTML = '<i class="tooltiptext"></i>';
+            copyCodeClipboardButton.title = 'Copy to clipboard';
+            copyCodeClipboardButton.setAttribute('aria-label', copyCodeClipboardButton.title);
+
+            buttons.insertBefore(copyCodeClipboardButton, buttons.firstChild);
+        }
+
+        let code_block = pre_block.querySelector("code");
+        if (window.ace && code_block.classList.contains("editable")) {
+            var undoChangesButton = document.createElement('button');
+            undoChangesButton.className = 'fa fa-history reset-button';
+            undoChangesButton.title = 'Undo changes';
+            undoChangesButton.setAttribute('aria-label', undoChangesButton.title);
+
+            buttons.insertBefore(undoChangesButton, buttons.firstChild);
+
+            undoChangesButton.addEventListener('click', function () {
+                let editor = window.ace.edit(code_block);
+                editor.setValue(editor.originalCode);
+                editor.clearSelection();
+            });
+        }
+    });
+})();
+
+(function themes() {
+    var html = document.querySelector('html');
+    var themeToggleButton = document.getElementById('theme-toggle');
+    var themePopup = document.getElementById('theme-list');
+    var themeColorMetaTag = document.querySelector('meta[name="theme-color"]');
+    var stylesheets = {
+        ayuHighlight: document.querySelector("[href$='ayu-highlight.css']"),
+        tomorrowNight: document.querySelector("[href$='tomorrow-night.css']"),
+        highlight: document.querySelector("[href$='highlight.css']"),
+    };
+
+    function showThemes() {
+        themePopup.style.display = 'block';
+        themeToggleButton.setAttribute('aria-expanded', true);
+        themePopup.querySelector("button#" + document.body.className).focus();
+    }
+
+    function hideThemes() {
+        themePopup.style.display = 'none';
+        themeToggleButton.setAttribute('aria-expanded', false);
+        themeToggleButton.focus();
+    }
+
+    function set_theme(theme, store = true) {
+        let ace_theme;
+
+        if (theme == 'coal' || theme == 'navy') {
+            stylesheets.ayuHighlight.disabled = true;
+            stylesheets.tomorrowNight.disabled = false;
+            stylesheets.highlight.disabled = true;
+
+            ace_theme = "ace/theme/tomorrow_night";
+        } else if (theme == 'ayu') {
+            stylesheets.ayuHighlight.disabled = false;
+            stylesheets.tomorrowNight.disabled = true;
+            stylesheets.highlight.disabled = true;
+            ace_theme = "ace/theme/tomorrow_night";
+        } else {
+            stylesheets.ayuHighlight.disabled = true;
+            stylesheets.tomorrowNight.disabled = true;
+            stylesheets.highlight.disabled = false;
+            ace_theme = "ace/theme/dawn";
+        }
+
+        setTimeout(function () {
+            themeColorMetaTag.content = getComputedStyle(document.body).backgroundColor;
+        }, 1);
+
+        if (window.ace && window.editors) {
+            window.editors.forEach(function (editor) {
+                editor.setTheme(ace_theme);
+            });
+        }
+
+        var previousTheme;
+        try { previousTheme = localStorage.getItem('mdbook-theme'); } catch (e) { }
+        if (previousTheme === null || previousTheme === undefined) { previousTheme = default_theme; }
+
+        if (store) {
+            try { localStorage.setItem('mdbook-theme', theme); } catch (e) { }
+        }
+
+        html.classList.remove(previousTheme);
+        html.classList.add(theme);
+    }
+
+    // Set theme
+    var theme;
+    try { theme = localStorage.getItem('mdbook-theme'); } catch(e) { }
+    if (theme === null || theme === undefined) { theme = default_theme; }
+
+    set_theme(theme, false);
+
+    themeToggleButton.addEventListener('click', function () {
+        if (themePopup.style.display === 'block') {
+            hideThemes();
+        } else {
+            showThemes();
+        }
+    });
+
+    themePopup.addEventListener('click', function (e) {
+        var theme = e.target.id || e.target.parentElement.id;
+        set_theme(theme);
+    });
+
+    themePopup.addEventListener('focusout', function(e) {
+        // e.relatedTarget is null in Safari and Firefox on macOS (see workaround below)
+        if (!!e.relatedTarget && !themeToggleButton.contains(e.relatedTarget) && !themePopup.contains(e.relatedTarget)) {
+            hideThemes();
+        }
+    });
+
+    // Should not be needed, but it works around an issue on macOS & iOS: https://github.com/rust-lang/mdBook/issues/628
+    document.addEventListener('click', function(e) {
+        if (themePopup.style.display === 'block' && !themeToggleButton.contains(e.target) && !themePopup.contains(e.target)) {
+            hideThemes();
+        }
+    });
+
+    document.addEventListener('keydown', function (e) {
+        if (e.altKey || e.ctrlKey || e.metaKey || e.shiftKey) { return; }
+        if (!themePopup.contains(e.target)) { return; }
+
+        switch (e.key) {
+            case 'Escape':
+                e.preventDefault();
+                hideThemes();
+                break;
+            case 'ArrowUp':
+                e.preventDefault();
+                var li = document.activeElement.parentElement;
+                if (li && li.previousElementSibling) {
+                    li.previousElementSibling.querySelector('button').focus();
+                }
+                break;
+            case 'ArrowDown':
+                e.preventDefault();
+                var li = document.activeElement.parentElement;
+                if (li && li.nextElementSibling) {
+                    li.nextElementSibling.querySelector('button').focus();
+                }
+                break;
+            case 'Home':
+                e.preventDefault();
+                themePopup.querySelector('li:first-child button').focus();
+                break;
+            case 'End':
+                e.preventDefault();
+                themePopup.querySelector('li:last-child button').focus();
+                break;
+        }
+    });
+})();
+
+(function sidebar() {
+    var html = document.querySelector("html");
+    var sidebar = document.getElementById("sidebar");
+    var sidebarScrollBox = document.getElementById("sidebar-scrollbox");
+    var sidebarLinks = document.querySelectorAll('#sidebar a');
+    var sidebarToggleButton = document.getElementById("sidebar-toggle");
+    var sidebarResizeHandle = document.getElementById("sidebar-resize-handle");
+    var firstContact = null;
+
+    function showSidebar() {
+        html.classList.remove('sidebar-hidden')
+        html.classList.add('sidebar-visible');
+        Array.from(sidebarLinks).forEach(function (link) {
+            link.setAttribute('tabIndex', 0);
+        });
+        sidebarToggleButton.setAttribute('aria-expanded', true);
+        sidebar.setAttribute('aria-hidden', false);
+        try { localStorage.setItem('mdbook-sidebar', 'visible'); } catch (e) { }
+    }
+
+
+    var sidebarAnchorToggles = document.querySelectorAll('#sidebar a.toggle');
+
+    function toggleSection(ev) {
+        ev.currentTarget.parentElement.classList.toggle('expanded');
+    }
+
+    Array.from(sidebarAnchorToggles).forEach(function (el) {
+        el.addEventListener('click', toggleSection);
+    });
+
+    function hideSidebar() {
+        html.classList.remove('sidebar-visible')
+        html.classList.add('sidebar-hidden');
+        Array.from(sidebarLinks).forEach(function (link) {
+            link.setAttribute('tabIndex', -1);
+        });
+        sidebarToggleButton.setAttribute('aria-expanded', false);
+        sidebar.setAttribute('aria-hidden', true);
+        try { localStorage.setItem('mdbook-sidebar', 'hidden'); } catch (e) { }
+    }
+
+    // Toggle sidebar
+    sidebarToggleButton.addEventListener('click', function sidebarToggle() {
+        if (html.classList.contains("sidebar-hidden")) {
+            showSidebar();
+        } else if (html.classList.contains("sidebar-visible")) {
+            hideSidebar();
+        } else {
+            if (getComputedStyle(sidebar)['transform'] === 'none') {
+                hideSidebar();
+            } else {
+                showSidebar();
+            }
+        }
+    });
+
+    sidebarResizeHandle.addEventListener('mousedown', initResize, false);
+
+    function initResize(e) {
+        window.addEventListener('mousemove', resize, false);
+        window.addEventListener('mouseup', stopResize, false);
+        html.classList.add('sidebar-resizing');
+    }
+    function resize(e) {
+        document.documentElement.style.setProperty('--sidebar-width', (e.clientX - sidebar.offsetLeft) + 'px');
+    }
+    //on mouseup remove windows functions mousemove & mouseup
+    function stopResize(e) {
+        html.classList.remove('sidebar-resizing');
+        window.removeEventListener('mousemove', resize, false);
+        window.removeEventListener('mouseup', stopResize, false);
+    }
+
+    document.addEventListener('touchstart', function (e) {
+        firstContact = {
+            x: e.touches[0].clientX,
+            time: Date.now()
+        };
+    }, { passive: true });
+
+    document.addEventListener('touchmove', function (e) {
+        if (!firstContact)
+            return;
+
+        var curX = e.touches[0].clientX;
+        var xDiff = curX - firstContact.x,
+            tDiff = Date.now() - firstContact.time;
+
+        if (tDiff < 250 && Math.abs(xDiff) >= 150) {
+            if (xDiff >= 0 && firstContact.x < Math.min(document.body.clientWidth * 0.25, 300))
+                showSidebar();
+            else if (xDiff < 0 && curX < 300)
+                hideSidebar();
+
+            firstContact = null;
+        }
+    }, { passive: true });
+
+    // Scroll sidebar to current active section
+    var activeSection = sidebar.querySelector(".active");
+    if (activeSection) {
+        sidebarScrollBox.scrollTop = activeSection.offsetTop;
+    }
+})();
+
+(function chapterNavigation() {
+    document.addEventListener('keydown', function (e) {
+        if (e.altKey || e.ctrlKey || e.metaKey || e.shiftKey) { return; }
+        if (window.search && window.search.hasFocus()) { return; }
+
+        switch (e.key) {
+            case 'ArrowRight':
+                e.preventDefault();
+                var nextButton = document.querySelector('.nav-chapters.next');
+                if (nextButton) {
+                    window.location.href = nextButton.href;
+                }
+                break;
+            case 'ArrowLeft':
+                e.preventDefault();
+                var previousButton = document.querySelector('.nav-chapters.previous');
+                if (previousButton) {
+                    window.location.href = previousButton.href;
+                }
+                break;
+        }
+    });
+})();
+
+(function clipboard() {
+    var clipButtons = document.querySelectorAll('.clip-button');
+
+    function hideTooltip(elem) {
+        elem.firstChild.innerText = "";
+        elem.className = 'fa fa-copy clip-button';
+    }
+
+    function showTooltip(elem, msg) {
+        elem.firstChild.innerText = msg;
+        elem.className = 'fa fa-copy tooltipped';
+    }
+
+    var clipboardSnippets = new ClipboardJS('.clip-button', {
+        text: function (trigger) {
+            hideTooltip(trigger);
+            let playpen = trigger.closest("pre");
+            return playpen_text(playpen);
+        }
+    });
+
+    Array.from(clipButtons).forEach(function (clipButton) {
+        clipButton.addEventListener('mouseout', function (e) {
+            hideTooltip(e.currentTarget);
+        });
+    });
+
+    clipboardSnippets.on('success', function (e) {
+        e.clearSelection();
+        showTooltip(e.trigger, "Copied!");
+    });
+
+    clipboardSnippets.on('error', function (e) {
+        showTooltip(e.trigger, "Clipboard error!");
+    });
+})();
+
+(function scrollToTop () {
+    var menuTitle = document.querySelector('.menu-title');
+
+    menuTitle.addEventListener('click', function () {
+        document.scrollingElement.scrollTo({ top: 0, behavior: 'smooth' });
+    });
+})();
+
+(function autoHideMenu() {
+    var menu = document.getElementById('menu-bar');
+
+    var previousScrollTop = document.scrollingElement.scrollTop;
+
+    document.addEventListener('scroll', function () {
+        if (menu.classList.contains('folded') && document.scrollingElement.scrollTop < previousScrollTop) {
+            menu.classList.remove('folded');
+        } else if (!menu.classList.contains('folded') && document.scrollingElement.scrollTop > previousScrollTop) {
+            menu.classList.add('folded');
+        }
+
+        if (!menu.classList.contains('bordered') && document.scrollingElement.scrollTop > 0) {
+            menu.classList.add('bordered');
+        }
+
+        if (menu.classList.contains('bordered') && document.scrollingElement.scrollTop === 0) {
+            menu.classList.remove('bordered');
+        }
+
+        previousScrollTop = Math.max(document.scrollingElement.scrollTop, 0);
+    }, { passive: true });
+})();

docs/creditsandresources.html

@@ -0,0 +1,234 @@
+<!DOCTYPE HTML>
+<html lang="en" class="sidebar-visible no-js light">
+    <head>
+        <!-- Book generated using mdBook -->
+        <meta charset="UTF-8">
+        <title>Credits and resources - </title>
+        
+
+        <meta content="text/html; charset=utf-8" http-equiv="Content-Type">
+        <meta name="description" content="">
+        <meta name="viewport" content="width=device-width, initial-scale=1">
+        <meta name="theme-color" content="#ffffff" />
+
+        <link rel="shortcut icon" href="favicon.png">
+        <link rel="stylesheet" href="css/variables.css">
+        <link rel="stylesheet" href="css/general.css">
+        <link rel="stylesheet" href="css/chrome.css">
+        <link rel="stylesheet" href="css/print.css" media="print">
+
+        <!-- Fonts -->
+        <link rel="stylesheet" href="FontAwesome/css/font-awesome.css">
+        <link href="https://fonts.googleapis.com/css?family=Open+Sans:300italic,400italic,600italic,700italic,800italic,400,300,600,700,800" rel="stylesheet" type="text/css">
+        <link href="https://fonts.googleapis.com/css?family=Source+Code+Pro:500" rel="stylesheet" type="text/css">
+
+        <!-- Highlight.js Stylesheets -->
+        <link rel="stylesheet" href="highlight.css">
+        <link rel="stylesheet" href="tomorrow-night.css">
+        <link rel="stylesheet" href="ayu-highlight.css">
+
+        <!-- Custom theme stylesheets -->
+        
+
+        
+    </head>
+    <body>
+        <!-- Provide site root to javascript -->
+        <script type="text/javascript">
+            var path_to_root = "";
+            var default_theme = window.matchMedia("(prefers-color-scheme: dark)").matches ? "light" : "light";
+        </script>
+
+        <!-- Work around some values being stored in localStorage wrapped in quotes -->
+        <script type="text/javascript">
+            try {
+                var theme = localStorage.getItem('mdbook-theme');
+                var sidebar = localStorage.getItem('mdbook-sidebar');
+
+                if (theme.startsWith('"') && theme.endsWith('"')) {
+                    localStorage.setItem('mdbook-theme', theme.slice(1, theme.length - 1));
+                }
+
+                if (sidebar.startsWith('"') && sidebar.endsWith('"')) {
+                    localStorage.setItem('mdbook-sidebar', sidebar.slice(1, sidebar.length - 1));
+                }
+            } catch (e) { }
+        </script>
+
+        <!-- Set the theme before any content is loaded, prevents flash -->
+        <script type="text/javascript">
+            var theme;
+            try { theme = localStorage.getItem('mdbook-theme'); } catch(e) { }
+            if (theme === null || theme === undefined) { theme = default_theme; }
+            var html = document.querySelector('html');
+            html.classList.remove('no-js')
+            html.classList.remove('light')
+            html.classList.add(theme);
+            html.classList.add('js');
+        </script>
+
+        <!-- Hide / unhide sidebar before it is displayed -->
+        <script type="text/javascript">
+            var html = document.querySelector('html');
+            var sidebar = 'hidden';
+            if (document.body.clientWidth >= 1080) {
+                try { sidebar = localStorage.getItem('mdbook-sidebar'); } catch(e) { }
+                sidebar = sidebar || 'visible';
+            }
+            html.classList.remove('sidebar-visible');
+            html.classList.add("sidebar-" + sidebar);
+        </script>
+
+        <nav id="sidebar" class="sidebar" aria-label="Table of contents">
+            <div id="sidebar-scrollbox" class="sidebar-scrollbox">
+                <ol class="chapter"><li class="expanded "><a href="about.html"><strong aria-hidden="true">1.</strong> About</a></li><li class="expanded "><a href="howitworks.html"><strong aria-hidden="true">2.</strong> How it works</a></li><li class="expanded "><a href="quickstart.html"><strong aria-hidden="true">3.</strong> Quick start</a></li><li class="expanded "><a href="usage.html"><strong aria-hidden="true">4.</strong> Usage</a></li><li class="expanded "><a href="api.html"><strong aria-hidden="true">5.</strong> Contract API</a></li><li class="expanded "><a href="libsemaphore.html"><strong aria-hidden="true">6.</strong> libsemaphore</a></li><li class="expanded "><a href="trustedsetup.html"><strong aria-hidden="true">7.</strong> Trusted setup</a></li><li class="expanded "><a href="audit.html"><strong aria-hidden="true">8.</strong> Security audit</a></li><li class="expanded "><a href="creditsandresources.html" class="active"><strong aria-hidden="true">9.</strong> Credits and resources</a></li></ol>
+            </div>
+            <div id="sidebar-resize-handle" class="sidebar-resize-handle"></div>
+        </nav>
+
+        <div id="page-wrapper" class="page-wrapper">
+
+            <div class="page">
+                
+                <div id="menu-bar" class="menu-bar">
+                    <div id="menu-bar-sticky-container">
+                        <div class="left-buttons">
+                            <button id="sidebar-toggle" class="icon-button" type="button" title="Toggle Table of Contents" aria-label="Toggle Table of Contents" aria-controls="sidebar">
+                                <i class="fa fa-bars"></i>
+                            </button>
+                            <button id="theme-toggle" class="icon-button" type="button" title="Change theme" aria-label="Change theme" aria-haspopup="true" aria-expanded="false" aria-controls="theme-list">
+                                <i class="fa fa-paint-brush"></i>
+                            </button>
+                            <ul id="theme-list" class="theme-popup" aria-label="Themes" role="menu">
+                                <li role="none"><button role="menuitem" class="theme" id="light">Light (default)</button></li>
+                                <li role="none"><button role="menuitem" class="theme" id="rust">Rust</button></li>
+                                <li role="none"><button role="menuitem" class="theme" id="coal">Coal</button></li>
+                                <li role="none"><button role="menuitem" class="theme" id="navy">Navy</button></li>
+                                <li role="none"><button role="menuitem" class="theme" id="ayu">Ayu</button></li>
+                            </ul>
+                            
+                            <button id="search-toggle" class="icon-button" type="button" title="Search. (Shortkey: s)" aria-label="Toggle Searchbar" aria-expanded="false" aria-keyshortcuts="S" aria-controls="searchbar">
+                                <i class="fa fa-search"></i>
+                            </button>
+                            
+                        </div>
+
+                        <h1 class="menu-title"></h1>
+
+                        <div class="right-buttons">
+                            <a href="print.html" title="Print this book" aria-label="Print this book">
+                                <i id="print-button" class="fa fa-print"></i>
+                            </a>
+                            
+                        </div>
+                    </div>
+                </div>
+
+                
+                <div id="search-wrapper" class="hidden">
+                    <form id="searchbar-outer" class="searchbar-outer">
+                        <input type="search" name="search" id="searchbar" name="searchbar" placeholder="Search this book ..." aria-controls="searchresults-outer" aria-describedby="searchresults-header">
+                    </form>
+                    <div id="searchresults-outer" class="searchresults-outer hidden">
+                        <div id="searchresults-header" class="searchresults-header"></div>
+                        <ul id="searchresults">
+                        </ul>
+                    </div>
+                </div>
+                
+
+                <!-- Apply ARIA attributes after the sidebar and the sidebar toggle button are added to the DOM -->
+                <script type="text/javascript">
+                    document.getElementById('sidebar-toggle').setAttribute('aria-expanded', sidebar === 'visible');
+                    document.getElementById('sidebar').setAttribute('aria-hidden', sidebar !== 'visible');
+                    Array.from(document.querySelectorAll('#sidebar a')).forEach(function(link) {
+                        link.setAttribute('tabIndex', sidebar === 'visible' ? 0 : -1);
+                    });
+                </script>
+
+                <div id="content" class="content">
+                    <main>
+                        <h1><a class="header" href="#credits" id="credits">Credits</a></h1>
+<ul>
+<li>Barry WhiteHat</li>
+<li>Chih Cheng Liang</li>
+<li>Kobi Gurkan</li>
+<li>Koh Wei Jie</li>
+<li>Harry Roberts</li>
+</ul>
+<p>Many thanks to:</p>
+<ul>
+<li>ABDK Consulting</li>
+<li>Jordi Baylina / iden3</li>
+<li>POA Network</li>
+<li>PepperSec</li>
+<li>Ethereum Foundation</li>
+</ul>
+<h1><a class="header" href="#resources" id="resources">Resources</a></h1>
+<p><a href="https://medium.com/coinmonks/to-mixers-and-beyond-presenting-semaphore-a-privacy-gadget-built-on-ethereum-4c8b00857c9b">To Mixers and Beyond: presenting Semaphore, a privacy gadget built on Ethereum</a> - Koh Wei Jie</p>
+<p><a href="https://www.youtube.com/watch?v=maDHYyj30kg">Privacy in Ethereum</a> - Barry WhiteHat at the Taipei Ethereum Meetup</p>
+<p><a href="https://www.youtube.com/watch?v=lv6iK9qezBY">Snarks for mixing, signaling and scaling by</a> - Barry WhiteHat at Devcon 4</p>
+<p><a href="https://www.youtube.com/watch?v=zBUo7G95wYE">Privacy in Ethereum</a> - Barry WhiteHat at Devcon 5</p>
+<p><a href="https://www.youtube.com/watch?v=GzVT16lFOHU">A trustless Ethereum mixer using zero-knowledge signalling</a> - Koh Wei Jie and Barry WhiteHat at Devcon 5</p>
+<p><a href="https://www.youtube.com/watch?v=7wd2aAN2jXI">Hands-on Applications of Zero-Knowledge Signalling</a> - Koh Wei Jie at Devcon 5</p>
+
+                    </main>
+
+                    <nav class="nav-wrapper" aria-label="Page navigation">
+                        <!-- Mobile navigation buttons -->
+                        
+                            <a rel="prev" href="audit.html" class="mobile-nav-chapters previous" title="Previous chapter" aria-label="Previous chapter" aria-keyshortcuts="Left">
+                                <i class="fa fa-angle-left"></i>
+                            </a>
+                        
+
+                        
+
+                        <div style="clear: both"></div>
+                    </nav>
+                </div>
+            </div>
+
+            <nav class="nav-wide-wrapper" aria-label="Page navigation">
+                
+                    <a href="audit.html" class="nav-chapters previous" title="Previous chapter" aria-label="Previous chapter" aria-keyshortcuts="Left">
+                        <i class="fa fa-angle-left"></i>
+                    </a>
+                
+
+                
+            </nav>
+
+        </div>
+
+        
+
+        
+
+        
+        
+        
+        <script type="text/javascript">
+            window.playpen_copyable = true;
+        </script>
+        
+
+        
+
+        
+        <script src="elasticlunr.min.js" type="text/javascript" charset="utf-8"></script>
+        <script src="mark.min.js" type="text/javascript" charset="utf-8"></script>
+        <script src="searcher.js" type="text/javascript" charset="utf-8"></script>
+        
+
+        <script src="clipboard.min.js" type="text/javascript" charset="utf-8"></script>
+        <script src="highlight.js" type="text/javascript" charset="utf-8"></script>
+        <script src="book.js" type="text/javascript" charset="utf-8"></script>
+
+        <!-- Custom JS scripts -->
+        
+
+        
+
+    </body>
+</html>

docs/css/chrome.css

@@ -0,0 +1,484 @@
+/* CSS for UI elements (a.k.a. chrome) */
+
+@import 'variables.css';
+
+::-webkit-scrollbar {
+    background: var(--bg);
+}
+::-webkit-scrollbar-thumb {
+    background: var(--scrollbar);
+}
+html {
+    scrollbar-color: var(--scrollbar) var(--bg);
+}
+#searchresults a,
+.content a:link,
+a:visited,
+a > .hljs {
+    color: var(--links);
+}
+
+/* Menu Bar */
+
+#menu-bar {
+    position: -webkit-sticky;
+    position: sticky;
+    top: 0;
+    z-index: 101;
+    margin: auto calc(0px - var(--page-padding));
+}
+#menu-bar > #menu-bar-sticky-container {
+    display: flex;
+    flex-wrap: wrap;
+    background-color: var(--bg);
+    border-bottom-color: var(--bg);
+    border-bottom-width: 1px;
+    border-bottom-style: solid;
+}
+.js #menu-bar > #menu-bar-sticky-container {
+    transition: transform 0.3s;
+}
+#menu-bar.bordered > #menu-bar-sticky-container  {
+    border-bottom-color: var(--table-border-color);
+}
+#menu-bar i, #menu-bar .icon-button {
+    position: relative;
+    padding: 0 8px;
+    z-index: 10;
+    line-height: var(--menu-bar-height);
+    cursor: pointer;
+    transition: color 0.5s;
+}
+@media only screen and (max-width: 420px) {
+    #menu-bar i, #menu-bar .icon-button {
+        padding: 0 5px;
+    }
+}
+
+.icon-button {
+    border: none;
+    background: none;
+    padding: 0;
+    color: inherit;
+}
+.icon-button i {
+    margin: 0;
+}
+
+.right-buttons {
+    margin: 0 15px;
+}
+.right-buttons a {
+    text-decoration: none;
+}
+
+html:not(.sidebar-visible) #menu-bar:not(:hover).folded > #menu-bar-sticky-container {
+    transform: translateY(calc(-10px - var(--menu-bar-height)));
+}
+
+.left-buttons {
+    display: flex;
+    margin: 0 5px;
+}
+.no-js .left-buttons {
+    display: none;
+}
+
+.menu-title {
+    display: inline-block;
+    font-weight: 200;
+    font-size: 2rem;
+    line-height: var(--menu-bar-height);
+    text-align: center;
+    margin: 0;
+    flex: 1;
+    white-space: nowrap;
+    overflow: hidden;
+    text-overflow: ellipsis;
+}
+.js .menu-title {
+    cursor: pointer;
+}
+
+.menu-bar,
+.menu-bar:visited,
+.nav-chapters,
+.nav-chapters:visited,
+.mobile-nav-chapters,
+.mobile-nav-chapters:visited,
+.menu-bar .icon-button,
+.menu-bar a i {
+    color: var(--icons);
+}
+
+.menu-bar i:hover,
+.menu-bar .icon-button:hover,
+.nav-chapters:hover,
+.mobile-nav-chapters i:hover {
+    color: var(--icons-hover);
+}
+
+/* Nav Icons */
+
+.nav-chapters {
+    font-size: 2.5em;
+    text-align: center;
+    text-decoration: none;
+
+    position: fixed;
+    top: 0;
+    bottom: 0;
+    margin: 0;
+    max-width: 150px;
+    min-width: 90px;
+
+    display: flex;
+    justify-content: center;
+    align-content: center;
+    flex-direction: column;
+
+    transition: color 0.5s, background-color 0.5s;
+}
+
+.nav-chapters:hover {
+    text-decoration: none;
+    background-color: var(--theme-hover);
+    transition: background-color 0.15s, color 0.15s;
+}
+
+.nav-wrapper {
+    margin-top: 50px;
+    display: none;
+}
+
+.mobile-nav-chapters {
+    font-size: 2.5em;
+    text-align: center;
+    text-decoration: none;
+    width: 90px;
+    border-radius: 5px;
+    background-color: var(--sidebar-bg);
+}
+
+.previous {
+    float: left;
+}
+
+.next {
+    float: right;
+    right: var(--page-padding);
+}
+
+@media only screen and (max-width: 1080px) {
+    .nav-wide-wrapper { display: none; }
+    .nav-wrapper { display: block; }
+}
+
+@media only screen and (max-width: 1380px) {
+    .sidebar-visible .nav-wide-wrapper { display: none; }
+    .sidebar-visible .nav-wrapper { display: block; }
+}
+
+/* Inline code */
+
+:not(pre) > .hljs {
+    display: inline;
+    padding: 0.1em 0.3em;
+    border-radius: 3px;
+}
+
+:not(pre):not(a) > .hljs {
+    color: var(--inline-code-color);
+    overflow-x: initial;
+}
+
+a:hover > .hljs {
+    text-decoration: underline;
+}
+
+pre {
+    position: relative;
+}
+pre > .buttons {
+    position: absolute;
+    z-index: 100;
+    right: 5px;
+    top: 5px;
+
+    color: var(--sidebar-fg);
+    cursor: pointer;
+}
+pre > .buttons :hover {
+    color: var(--sidebar-active);
+}
+pre > .buttons i {
+    margin-left: 8px;
+}
+pre > .buttons button {
+    color: inherit;
+    background: transparent;
+    border: none;
+    cursor: inherit;
+}
+pre > .result {
+    margin-top: 10px;
+}
+
+/* Search */
+
+#searchresults a {
+    text-decoration: none;
+}
+
+mark {
+    border-radius: 2px;
+    padding: 0 3px 1px 3px;
+    margin: 0 -3px -1px -3px;
+    background-color: var(--search-mark-bg);
+    transition: background-color 300ms linear;
+    cursor: pointer;
+}
+
+mark.fade-out {
+    background-color: rgba(0,0,0,0) !important;
+    cursor: auto;
+}
+
+.searchbar-outer {
+    margin-left: auto;
+    margin-right: auto;
+    max-width: var(--content-max-width);
+}
+
+#searchbar {
+    width: 100%;
+    margin: 5px auto 0px auto;
+    padding: 10px 16px;
+    transition: box-shadow 300ms ease-in-out;
+    border: 1px solid var(--searchbar-border-color);
+    border-radius: 3px;
+    background-color: var(--searchbar-bg);
+    color: var(--searchbar-fg);
+}
+#searchbar:focus,
+#searchbar.active {
+    box-shadow: 0 0 3px var(--searchbar-shadow-color);
+}
+
+.searchresults-header {
+    font-weight: bold;
+    font-size: 1em;
+    padding: 18px 0 0 5px;
+    color: var(--searchresults-header-fg);
+}
+
+.searchresults-outer {
+    margin-left: auto;
+    margin-right: auto;
+    max-width: var(--content-max-width);
+    border-bottom: 1px dashed var(--searchresults-border-color);
+}
+
+ul#searchresults {
+    list-style: none;
+    padding-left: 20px;
+}
+ul#searchresults li {
+    margin: 10px 0px;
+    padding: 2px;
+    border-radius: 2px;
+}
+ul#searchresults li.focus {
+    background-color: var(--searchresults-li-bg);
+}
+ul#searchresults span.teaser {
+    display: block;
+    clear: both;
+    margin: 5px 0 0 20px;
+    font-size: 0.8em;
+}
+ul#searchresults span.teaser em {
+    font-weight: bold;
+    font-style: normal;
+}
+
+/* Sidebar */
+
+.sidebar {
+    position: fixed;
+    left: 0;
+    top: 0;
+    bottom: 0;
+    width: var(--sidebar-width);
+    font-size: 0.875em;
+    box-sizing: border-box;
+    -webkit-overflow-scrolling: touch;
+    overscroll-behavior-y: contain;
+    background-color: var(--sidebar-bg);
+    color: var(--sidebar-fg);
+}
+.sidebar-resizing {
+    -moz-user-select: none;
+    -webkit-user-select: none;
+    -ms-user-select: none;
+    user-select: none;
+}
+.js:not(.sidebar-resizing) .sidebar {
+    transition: transform 0.3s; /* Animation: slide away */
+}
+.sidebar code {
+    line-height: 2em;
+}
+.sidebar .sidebar-scrollbox {
+    overflow-y: auto;
+    position: absolute;
+    top: 0;
+    bottom: 0;
+    left: 0;
+    right: 0;
+    padding: 10px 10px;
+}
+.sidebar .sidebar-resize-handle {
+    position: absolute;
+    cursor: col-resize;
+    width: 0;
+    right: 0;
+    top: 0;
+    bottom: 0;
+}
+.js .sidebar .sidebar-resize-handle {
+    cursor: col-resize;
+    width: 5px;
+}
+.sidebar-hidden .sidebar {
+    transform: translateX(calc(0px - var(--sidebar-width)));
+}
+.sidebar::-webkit-scrollbar {
+    background: var(--sidebar-bg);
+}
+.sidebar::-webkit-scrollbar-thumb {
+    background: var(--scrollbar);
+}
+
+.sidebar-visible .page-wrapper {
+    transform: translateX(var(--sidebar-width));
+}
+@media only screen and (min-width: 620px) {
+    .sidebar-visible .page-wrapper {
+        transform: none;
+        margin-left: var(--sidebar-width);
+    }
+}
+
+.chapter {
+    list-style: none outside none;
+    padding-left: 0;
+    line-height: 2.2em;
+}
+
+.chapter ol {
+    width: 100%;
+}
+
+.chapter li {
+    display: flex;
+    color: var(--sidebar-non-existant);
+}
+.chapter li a {
+    display: block;
+    padding: 0;
+    text-decoration: none;
+    color: var(--sidebar-fg);
+}
+
+.chapter li a:hover {
+    color: var(--sidebar-active);
+}
+
+.chapter li a.active {
+    color: var(--sidebar-active);
+}
+
+.chapter li > a.toggle {
+    cursor: pointer;
+    display: block;
+    margin-left: auto;
+    padding: 0 10px;
+    user-select: none;
+    opacity: 0.68;
+}
+
+.chapter li > a.toggle div {
+    transition: transform 0.5s;
+}
+
+/* collapse the section */
+.chapter li:not(.expanded) + li > ol {
+    display: none;
+}
+
+.chapter li.expanded > a.toggle div {
+    transform: rotate(90deg);
+}
+
+.spacer {
+    width: 100%;
+    height: 3px;
+    margin: 5px 0px;
+}
+.chapter .spacer {
+    background-color: var(--sidebar-spacer);
+}
+
+@media (-moz-touch-enabled: 1), (pointer: coarse) {
+    .chapter li a { padding: 5px 0; }
+    .spacer { margin: 10px 0; }
+}
+
+.section {
+    list-style: none outside none;
+    padding-left: 20px;
+    line-height: 1.9em;
+}
+
+/* Theme Menu Popup */
+
+.theme-popup {
+    position: absolute;
+    left: 10px;
+    top: var(--menu-bar-height);
+    z-index: 1000;
+    border-radius: 4px;
+    font-size: 0.7em;
+    color: var(--fg);
+    background: var(--theme-popup-bg);
+    border: 1px solid var(--theme-popup-border);
+    margin: 0;
+    padding: 0;
+    list-style: none;
+    display: none;
+}
+.theme-popup .default {
+    color: var(--icons);
+}
+.theme-popup .theme {
+    width: 100%;
+    border: 0;
+    margin: 0;
+    padding: 2px 10px;
+    line-height: 25px;
+    white-space: nowrap;
+    text-align: left;
+    cursor: pointer;
+    color: inherit;
+    background: inherit;
+    font-size: inherit;
+}
+.theme-popup .theme:hover {
+    background-color: var(--theme-hover);
+}
+.theme-popup .theme:hover:first-child,
+.theme-popup .theme:hover:last-child {
+    border-top-left-radius: inherit;
+    border-top-right-radius: inherit;
+}

docs/css/general.css

@@ -0,0 +1,159 @@
+/* Base styles and content styles */
+
+@import 'variables.css';
+
+:root {
+    /* Browser default font-size is 16px, this way 1 rem = 10px */
+    font-size: 62.5%;
+}
+
+html {
+    font-family: "Open Sans", sans-serif;
+    color: var(--fg);
+    background-color: var(--bg);
+    text-size-adjust: none;
+}
+
+body {
+    margin: 0;
+    font-size: 1.6rem;
+    overflow-x: hidden;
+}
+
+code {
+    font-family: "Source Code Pro", Consolas, "Ubuntu Mono", Menlo, "DejaVu Sans Mono", monospace, monospace !important;
+    font-size: 0.875em; /* please adjust the ace font size accordingly in editor.js */
+}
+
+.left { float: left; }
+.right { float: right; }
+.boring { opacity: 0.6; }
+.hide-boring .boring { display: none; }
+.hidden { display: none; }
+
+h2, h3 { margin-top: 2.5em; }
+h4, h5 { margin-top: 2em; }
+
+.header + .header h3,
+.header + .header h4,
+.header + .header h5 {
+    margin-top: 1em;
+}
+
+h1 a.header:target::before,
+h2 a.header:target::before,
+h3 a.header:target::before,
+h4 a.header:target::before {
+    display: inline-block;
+    content: "»";
+    margin-left: -30px;
+    width: 30px;
+}
+
+h1 a.header:target,
+h2 a.header:target,
+h3 a.header:target,
+h4 a.header:target {
+    scroll-margin-top: calc(var(--menu-bar-height) + 0.5em);
+}
+
+.page {
+    outline: 0;
+    padding: 0 var(--page-padding);
+}
+.page-wrapper {
+    box-sizing: border-box;
+}
+.js:not(.sidebar-resizing) .page-wrapper {
+    transition: margin-left 0.3s ease, transform 0.3s ease; /* Animation: slide away */
+}
+
+.content {
+    overflow-y: auto;
+    padding: 0 15px;
+    padding-bottom: 50px;
+}
+.content main {
+    margin-left: auto;
+    margin-right: auto;
+    max-width: var(--content-max-width);
+}
+.content a { text-decoration: none; }
+.content a:hover { text-decoration: underline; }
+.content img { max-width: 100%; }
+.content .header:link,
+.content .header:visited {
+    color: var(--fg);
+}
+.content .header:link,
+.content .header:visited:hover {
+    text-decoration: none;
+}
+
+table {
+    margin: 0 auto;
+    border-collapse: collapse;
+}
+table td {
+    padding: 3px 20px;
+    border: 1px var(--table-border-color) solid;
+}
+table thead {
+    background: var(--table-header-bg);
+}
+table thead td {
+    font-weight: 700;
+    border: none;
+}
+table thead th {
+    padding: 3px 20px;
+}
+table thead tr {
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docs/howitworks.html

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+<!DOCTYPE HTML>
+<html lang="en" class="sidebar-visible no-js light">
+    <head>
+        <!-- Book generated using mdBook -->
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+
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+
+                <div id="content" class="content">
+                    <main>
+                        <h1><a class="header" href="#how-it-works" id="how-it-works">How it works</a></h1>
+<h2><a class="header" href="#inserting-identities" id="inserting-identities">Inserting identities</a></h2>
+<p>An identity is comprised of the following information:</p>
+<ol>
+<li>An <a href="https://en.wikipedia.org/wiki/EdDSA">EdDSA</a> private key. Note that it is
+<em>not</em> an Ethereum private key.</li>
+<li>An identity nullifier, whih is a random 32-byte value.</li>
+<li>An identity trapdoor, whih is a random 32-byte value.</li>
+</ol>
+<p>An identity commitment is the Pedersen hash of:</p>
+<ol>
+<li>The public key associated with the identity's private key.</li>
+<li>The identity nullifier.</li>
+<li>The identity trapdoor.</li>
+</ol>
+<p>To register an identity, the user must insert their identity commitment into
+Semaphore's identity tree. They can do this by calling the Semaphore contract's
+<code>insertIdentity(uint256 _identityCommitment)</code> function. See the <a href="./api.html">API
+reference</a> for more information.</p>
+<h2><a class="header" href="#broadcasting-signals" id="broadcasting-signals">Broadcasting signals</a></h2>
+<p>To broadcast a signal, the user must invoke this Semaphore contract function:</p>
+<pre><code>broadcastSignal(
+    bytes memory _signal,
+    uint256[8] memory _proof,
+    uint256 _root,
+    uint256 _nullifiersHash,
+    uint232 _externalNullifier
+)
+</code></pre>
+<ul>
+<li><code>_signal</code>: the signal to broadcast.</li>
+<li><code>_proof</code>: a zk-SNARK proof (see below).</li>
+<li><code>_root</code>: The root of the identity tree, where the user's identity commitment
+is the last-inserted leaf.</li>
+<li><code>_nullifiersHash</code>: A uniquely derived hash of the external nullifier, user's
+identity nullifier, and the Merkle path index to their identity commitment.
+It ensures that a user cannot broadcast a signal with the same external
+nullifier more than once.</li>
+<li><code>_externalNullifier</code>: The external nullifier at which the signal is
+broadcast.</li>
+</ul>
+<p>To zk-SNARK proof must satisfy the constraints created by Semaphore's zk-SNARK
+circuit as described below:</p>
+<h3><a class="header" href="#the-zk-snark-circuit" id="the-zk-snark-circuit">The zk-SNARK circuit</a></h3>
+<p>The <a href="./circuits/circom/semaphore-base.circom">semaphore-base.circom</a> circuit
+helps to prove the following:</p>
+<h3><a class="header" href="#that-the-identity-commitment-exists-in-the-merkle-tree" id="that-the-identity-commitment-exists-in-the-merkle-tree">That the identity commitment exists in the Merkle tree</a></h3>
+<p><strong>Private inputs:</strong></p>
+<ul>
+<li><code>identity_pk</code>: the user's EdDSA public key</li>
+<li><code>identity_nullifier</code>: a random 32-byte value which the user should save</li>
+<li><code>identity_trapdoor</code>: a random 32-byte value which the user should save</li>
+<li><code>identity_path_elements</code>: the values along the Merkle path to the
+user's identity commitment</li>
+<li><code>identity_path_index[n_levels]</code>: the direction (left/right) per tree level
+corresponding to the Merkle path to the user's identity commitment</li>
+</ul>
+<p><strong>Public inputs:</strong></p>
+<ul>
+<li><code>root</code>: The Merkle root of the identity tree</li>
+</ul>
+<p><strong>Procedure:</strong></p>
+<p>The circuit hashes the public key, identity nullifier, and identity trapdoor to
+generate an <strong>identity commitment</strong>. It then verifies the Merkle proof against
+the Merkle root and the identity commitment.</p>
+<h3><a class="header" href="#that-the-signal-was-only-broadcasted-once" id="that-the-signal-was-only-broadcasted-once">That the signal was only broadcasted once</a></h3>
+<p><strong>Private inputs:</strong></p>
+<ul>
+<li><code>identity_nullifier</code>: as above</li>
+<li><code>identity_path_index</code>: as above</li>
+</ul>
+<p><strong>Public inputs:</strong></p>
+<ul>
+<li><code>external_nullifier</code>: the 29-byte external nullifier - see above</li>
+<li><code>nullifiers_hash</code>: the hash of the identity nullifier, external nullifier,
+and Merkle path index (<code>identity_path_index</code>)</li>
+</ul>
+<p><strong>Procedure:</strong></p>
+<p>The circuit hashes the given identity nullifier, external nullifier, and Merkle
+path index, and checks that it matches the given nullifiers hash. Additionally,
+the smart contract ensures that it has not previously seen this nullifiers
+hash. This way, double-signalling is impossible.</p>
+<h3><a class="header" href="#that-the-signal-was-truly-broadcasted-by-the-user-who-generated-the-proof" id="that-the-signal-was-truly-broadcasted-by-the-user-who-generated-the-proof">That the signal was truly broadcasted by the user who generated the proof</a></h3>
+<p><strong>Private inputs:</strong></p>
+<ul>
+<li><code>identity_pk</code>: as above</li>
+<li><code>auth_sig_r</code>: the <code>r</code> value of the signature of the signal</li>
+<li><code>auth_sig_s</code>: the <code>s</code> value of the signature of the signal</li>
+</ul>
+<p><strong>Public inputs:</strong></p>
+<ul>
+<li><code>signal_hash</code>: the hash of the signal</li>
+<li><code>external_nullifier</code>: the 29-byte external nullifier - see above</li>
+</ul>
+<p><strong>Procedure:</strong></p>
+<p>The circuit hashes the signal hash and the external nullifier, and verifies
+this output against the given public key and signature. This ensures the
+authenticity of the signal and prevents front-running attacks.</p>
+<h2><a class="header" href="#cryptographic-primitives" id="cryptographic-primitives">Cryptographic primitives</a></h2>
+<p>Semaphore uses MiMC for the Merkle tree, Pedersen commmitments for the identity
+commitments, Blake2 for the nullifiers hash, and EdDSA for the signature.</p>
+<p>MiMC is a relatively new hash function. We use the recommended MiMC
+construction from <a href="https://eprint.iacr.org/2016/492.pdf">Albrecht et al</a>, and
+there is a prize to break MiMC at <a href="http://mimchash.org">http://mimchash.org</a>
+which has not been claimed yet.</p>
+<p>We have also implemented a version of Semaphore which uses the Poseidon hash
+function for the Merkle tree and EdDSA signature verification. This may have
+better security than MiMC, allows identity insertions to save about 20% gas,
+and roughly halves the proving time. Note, however, that the Poseidon-related
+circuits and EVM bytecode generator have not been audited, so use it with
+caution. To use it, checkout the <code>feat/poseidon</code> branch of this repository.</p>
+
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+                        <h1><a class="header" href="#about" id="about">About</a></h1>
+<p><a href="https://github.com/appliedzkp/semaphore">Semaphore</a> is a zero-knowledge gadget
+which allows Ethereum users to prove their membership of a set which they had
+previously joined without revealing their original identity. At the same time,
+it allows users to signal their endorsement of an arbitrary string. It is
+designed to be a simple and generic privacy layer for Ethereum dApps. Use cases
+include private voting, whistleblowing, mixers, and anonymous authentication.
+Finally, it provides a simple built-in mechanism to prevent double-signalling
+or double-spending.</p>
+<p>This gadget comprises of smart contracts and
+<a href="https://z.cash/technology/zksnarks/">zero-knowledge</a> components which work in
+tandem. The Semaphore smart contract handles state, permissions, and proof
+verification on-chain. The zero-knowledge components work off-chain to allow
+the user to generate proofs, which allow the smart contract to update its state
+if these proofs are valid.</p>
+<p>Semaphore is designed for smart contract and dApp developers, not end users.
+Developers should abstract its features away in order to provide user-friendly
+privacy.</p>
+<p>Try a simple demo <a href="https://weijiekoh.github.io/semaphore-ui/">here</a> or read a
+high-level description of Semaphore
+<a href="https://medium.com/coinmonks/to-mixers-and-beyond-presenting-semaphore-a-privacy-gadget-built-on-ethereum-4c8b00857c9b">here</a>.</p>
+<h2><a class="header" href="#basic-features" id="basic-features">Basic features</a></h2>
+<p>In sum, Semaphore provides the ability to:</p>
+<ol>
+<li>
+<p>Register an identity in a smart contract, and then:</p>
+</li>
+<li>
+<p>Broadcast a signal:</p>
+<ul>
+<li>
+<p>Anonymously prove that their identity is in the set of registered
+identities, and at the same time:</p>
+</li>
+<li>
+<p>Publicly store an arbitrary string in the contract, if and only if that
+string is unique to the user and the contract’s current external
+nullifier, which is a unique value akin to a topic. This means that
+double-signalling the same message under the same external nullifier is
+not possible.</p>
+</li>
+</ul>
+</li>
+</ol>
+<h3><a class="header" href="#about-external-nullifiers" id="about-external-nullifiers">About external nullifiers</a></h3>
+<p>Think of an external nullifier as a voting booth where each user may only cast
+one vote. If they try to cast a second vote a the same booth, that vote is
+invalid.</p>
+<p>An external nullifier is any 29-byte value. Semaphore always starts with one
+external nullifier, which is set upon contract deployment. The owner of the
+Semaphore contract may add more external nullifiers, deactivate, or reactivate
+existing ones.</p>
+<p>The first time a particular user broadcasts a signal to an active external
+nullifier <code>n</code>, and if the user's proof of membership of the set of registered
+users is valid, the transaction will succeed. The second time she does so to
+the same <code>n</code>, however, her transaction will fail.</p>
+<p>Additionally, all signals broadcast transactions to a deactivated external
+nullifier will fail.</p>
+<p>Each client application must use the above features of Semaphore in a unique
+way to achieve its privacy goals. A mixer, for instance, would use one external
+nullifier as such:</p>
+<table><thead><tr><th>Signal</th><th>External nullifier</th></tr></thead><tbody>
+<tr><td>The hash of the recipient's address, relayer's address, and the relayer's fee</td><td>The mixer contract's address</td></tr>
+</tbody></table>
+<p>This allows anonymous withdrawals of funds (via a transaction relayer, who is
+rewarded with a fee), and prevents double-spending as there is only one
+external nullifier.</p>
+<p>An anonymous voting app would be configured differently:</p>
+<table><thead><tr><th>Signal</th><th>External nullifier</th></tr></thead><tbody>
+<tr><td>The hash of the respondent's answer</td><td>The hash of the question</td></tr>
+</tbody></table>
+<p>This allows any user to vote with an arbitary response (e.g. yes, no, or maybe)
+to any question. The user, however, can only vote once per question.</p>
+<h2><a class="header" href="#about-the-code" id="about-the-code">About the code</a></h2>
+<p>This repository contains the code for Semaphore's contracts written in
+Soliidty, and zk-SNARK circuits written in
+<a href="https://github.com/iden3/circom">circom</a>. It also contains Typescript code to
+execute tests.</p>
+<p>The code has been audited by ABDK Consulting. Their suggested security and
+efficiency fixes have been applied.</p>
+<p>A multi-party computation to produce the zk-SNARK proving and verification keys
+for Semaphore will begin in the near future.</p>
+
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+                        <h1><a class="header" href="#libsemaphore" id="libsemaphore">libsemaphore</a></h1>
+<p><a href="https://www.npmjs.com/package/libsemaphore"><code>libsemaphore</code></a> is a helper
+library for Semaphore written in Typescript. Any dApp written in Javascript or
+Typescript should use it as it provides useful abstractions over common tasks
+and objects, such as identities and proof generation.</p>
+<p>Note that only v1.0.14 and above works with the Semaphore code in this
+repository. v0.0.x is compatible with the pre-audited Semaphore code.</p>
+<h2><a class="header" href="#available-types-interfaces-and-functions" id="available-types-interfaces-and-functions">Available types, interfaces, and functions</a></h2>
+<h3><a class="header" href="#types" id="types">Types</a></h3>
+<p><strong><code>SnarkBigInt</code></strong></p>
+<p>A big integer type compatible with the <code>snarkjs</code> library. Note that it is not
+advisable to mix variables of this type with <code>bigNumber</code>s or <code>BigInt</code>s.
+Encapsulates <code>snarkjs.bigInt</code>.</p>
+<p><strong><code>EddsaPrivateKey</code></strong></p>
+<p>An <a href="https://tools.ietf.org/html/rfc8032">EdDSA</a> private key which should be 32
+bytes long. Encapsulates a <a href="https://nodejs.org/api/buffer.html"><code>Buffer</code></a>.</p>
+<p><strong><code>EddsaPublicKey</code></strong></p>
+<p>An EdDSA public key. Encapsulates an array of <code>SnarkBigInt</code>s.</p>
+<p><strong><code>SnarkProvingKey</code></strong></p>
+<p>A proving key, which when used with a secret <em>witness</em>, generates a zk-SNARK
+proof about said witness. Encapsulates a <code>Buffer</code>.</p>
+<p><strong><code>SnarkVerifyingKey</code></strong></p>
+<p>A verifying key which when used with public inputs to a zk-SNARK and a
+<code>SnarkProof</code>, can prove the proof's validity. Encapsulates a <code>Buffer</code>.</p>
+<p><strong><code>SnarkWitness</code></strong></p>
+<p>The secret inputs to a zk-SNARK. Encapsulates an array of <code>SnarkBigInt</code>s.</p>
+<p><strong><code>SnarkPublicSignals</code></strong></p>
+<p>The public inputs to a zk-SNARK. Encapsulates an array of <code>SnarkBigInt</code>s.</p>
+<h3><a class="header" href="#interfaces" id="interfaces">Interfaces</a></h3>
+<p><strong><code>EddsaKeyPair</code></strong></p>
+<p>Encapsulates an <code>EddsaPublicKey</code> and an <code>EddsaPrivateKey</code>.</p>
+<pre><code class="language-ts">interface EddsaKeyPair {
+    pubKey: EddsaPublicKey,
+    privKey: EddsaPrivateKey,
+}
+</code></pre>
+<p><strong><code>Identity</code></strong></p>
+<p>Encapsulates all information required to generate an identity commitment, and
+is crucial to creating <code>SnarkProof</code>s to broadcast signals.</p>
+<pre><code class="language-ts">interface Identity {
+    keypair: EddsaKeyPair,
+    identityNullifier: SnarkBigInt,
+    identityTrapdoor: SnarkBigInt,
+}
+</code></pre>
+<p><strong><code>SnarkProof</code></strong></p>
+<p>Note that <code>broadcastSignal()</code> accepts a <code>uint256[8]</code> array for its <code>_proof</code>
+parameter. See <code>genBroadcastSignalParams()</code>.</p>
+<pre><code class="language-ts">interface SnarkProof {
+    pi_a: SnarkBigInt[]
+    pi_b: SnarkBigInt[][]
+    pi_c: SnarkBigInt[]
+}
+</code></pre>
+<h3><a class="header" href="#functions" id="functions">Functions</a></h3>
+<p><strong><code>genPubKey(privKey: EddsaPrivateKey): EddsaPublicKey</code></strong></p>
+<p>Generates a public EdDSA key from a supplied private key. To generate a private
+key, use <code>crypto.randomBytes(32)</code> where <code>crypto</code> is the built-in Node or
+browser module.</p>
+<p><strong><code>genIdentity(): Identity</code></strong></p>
+<p>This is a convenience function to generate a fresh and random <code>Identity</code>. That
+is, the 32-byte private key for the <code>EddsaKeyPair</code> is randomly generated, as
+are the distinct 31-byte identity nullifier and the 31-byte identity trapdoor
+values.</p>
+<p><strong><code>serialiseIdentity(identity: Identity): string</code></strong></p>
+<p>Converts an <code>Identity</code> into a JSON string which looks like this:</p>
+<pre><code class="language-text">[&quot;e82cc2b8654705e427df423c6300307a873a2e637028fab3163cf95b18bb172e&quot;,&quot;a02e517dfb3a4184adaa951d02bfe0fe092d1ee34438721d798db75b8db083&quot;,&quot;15c6540bf7bddb0616984fccda7e954a0fb5ea4679ac686509dc4bd7ba9c3b&quot;]
+</code></pre>
+<p>You can also spell this function as <code>serializeIdentity</code>.</p>
+<p>To convert this string back into an <code>Identity</code>, use <code>unSerialiseIdentity()</code>.</p>
+<p><strong><code>unSerialiseIdentity(string: serialisedId): Identity</code></strong></p>
+<p>Converts the <code>string</code> output of <code>serialiseIdentity()</code> to an <code>Identity</code>.</p>
+<p>You can also spell this function as <code>unSerializeIdentity</code>.</p>
+<p><strong><code>genIdentityCommitment(identity: Identity): SnarkBigInt</code></strong></p>
+<p>Generates an identity commitment, which is the hash of the public key, the
+identity nullifier, and the identity trapdoor.</p>
+<p><strong><code>async genProof(witness: SnarkWitness, provingKey: SnarkProvingKey): SnarkProof</code></strong></p>
+<p>Generates a <code>SnarkProof</code>, which can be sent to the Semaphore contract's
+<code>broadcastSignal()</code> function. It can also be verified off-chain using
+<code>verifyProof()</code> below.</p>
+<p><strong><code>genPublicSignals(witness: SnarkWitness, circuit: SnarkCircuit): SnarkPublicSignals</code></strong></p>
+<p>Extracts the public signals to be supplied to the contract or <code>verifyProof()</code>.</p>
+<p><strong><code>verifyProof(verifyingKey: SnarkVerifyingKey, proof: SnarkProof, publicSignals: SnarkPublicSignals): boolean</code></strong></p>
+<p>Returns <code>true</code> if the given <code>proof</code> is valid, given the correct verifying key
+and public signals.</p>
+<p>Returns <code>false</code> otherwise.</p>
+<p><strong><code>signMsg(privKey: EddsaPrivateKey, msg: SnarkBigInt): EdDSAMiMcSpongeSignature)</code></strong></p>
+<p>Encapsualtes <code>circomlib.eddsa.signMiMCSponge</code> to sign a message <code>msg</code> using private key <code>privKey</code>.</p>
+<p><strong><code>verifySignature(msg: SnarkBigInt, signature: EdDSAMiMcSpongeSignature, pubKey: EddsaPublicKey)</code>: boolean</strong></p>
+<p>Returns <code>true</code> if the cryptographic <code>signature</code> of the signed <code>msg</code> is from the
+private key associated with <code>pubKey</code>.</p>
+<p>Returns <code>false</code> otherwise.</p>
+<p><strong><code>setupTree(levels: number, prefix: string): MerkleTree</code></strong></p>
+<p>Returns a Merkle tree created using
+<a href="https://www.npmjs.com/package/semaphore-merkle-tree"><code>semaphore-merkle-tree</code></a>
+with the same number of levels which the Semaphore zk-SNARK circuit expects.
+This tree is also configured to use <code>MimcSpongeHasher</code>, which is also what the
+circuit expects.</p>
+<p><code>levels</code> sets the number of levels of the tree. A tree with 20 levels, for
+instance, supports up to 1048576 deposits.</p>
+<p><strong><code>genCircuit(circuitDefinition: any)</code></strong></p>
+<p>Returns a <code>new snarkjs.Circuit(circuitDefinition)</code>. The <code>circuitDefinition</code>
+object should be the <code>JSON.parse</code>d result of the <code>circom</code> command which
+converts a <code>.circom</code> file to a <code>.json</code> file.</p>
+<p><strong><code>async genWitness(...)</code></strong></p>
+<p>This function has the following signature:</p>
+<pre><code class="language-ts">const genWitness = async (
+    signal: string,
+    circuit: SnarkCircuit,
+    identity: Identity,
+    idCommitments: SnarkBigInt[] | BigInt[] | ethers.utils.BigNumber[],
+    treeDepth: number,
+    externalNullifier: SnarkBigInt,
+)
+</code></pre>
+<ul>
+<li><code>signal</code> is the string you wish to broadcast.</li>
+<li><code>circuit</code> is the output of <code>genCircuit()</code>.</li>
+<li><code>identity</code> is the <code>Identity</code> whose identity commitment you want to prove is
+in the set of registered identities.</li>
+<li><code>idCommitments</code> is an array of registered identity commmitments; i.e. the
+leaves of the tree.</li>
+<li><code>treeDepth</code> is the number of levels which the Merkle tree used has</li>
+<li><code>externalNullifier</code> is the current external nullifier</li>
+</ul>
+<p>It returns an object as such:</p>
+<ul>
+<li><code>witness</code>: The witness to pass to <code>genProof()</code>.</li>
+<li><code>signal</code>: The computed signal for Semaphore. This is the hash of the
+recipient's address, relayer's address, and fee.</li>
+<li><code>signalHash</code>: The hash of the computed signal.</li>
+<li><code>msg</code>: The hash of the external nullifier and the signal hash</li>
+<li><code>signature</code>: The signature on the above msg.</li>
+<li><code>tree</code>: The Merkle tree object after it has been updated with the identity commitment</li>
+<li><code>identityPath</code>: The Merkle path to the identity commmitment</li>
+<li><code>identityPathIndex</code>: The leaf index of the identity commitment</li>
+<li><code>identityPathElements</code>: The elements along the above Merkle path</li>
+</ul>
+<p>Only <code>witness</code> is essential to generate the proof; the other data is only
+useful for debugging and additional off-chain checks, such as verifying the
+signature and the Merkle tree root.</p>
+<p><strong><code>formatForVerifierContract = (proof: SnarkProof, publicSignals: SnarkPublicSignals</code></strong></p>
+<p>Converts the data in <code>proof</code> and <code>publicSignals</code> to strings and rearranges
+elements of <code>proof.pi_b</code> so that <code>snarkjs</code>'s <code>verifier.sol</code> will accept it.
+To be specific, it returns an object as such:</p>
+<pre><code class="language-ts">{
+    a: [ proof.pi_a[0].toString(), proof.pi_a[1].toString() ],
+    b: [ 
+         [ proof.pi_b[0][1].toString(), proof.pi_b[0][0].toString() ],
+         [ proof.pi_b[1][1].toString(), proof.pi_b[1][0].toString() ],
+    ],
+    c: [ proof.pi_c[0].toString(), proof.pi_c[1].toString() ],
+    input: publicSignals.map((x) =&gt; x.toString()),
+}
+</code></pre>
+<p><strong><code>stringifyBigInts = (obj: any) =&gt; object</code></strong></p>
+<p>Encapsulates <code>snarkjs.stringifyBigInts()</code>. Makes it easy to convert <code>SnarkProof</code>s to JSON. </p>
+<p><strong><code>unstringifyBigInts = (obj: any) =&gt; object</code></strong></p>
+<p>Encapsulates <code>snarkjs.unstringifyBigInts()</code>. Makes it easy to convert JSON to <code>SnarkProof</code>s.</p>
+<p><strong><code>genExternalNullifier = (plaintext: string) =&gt; string</code></strong></p>
+<p>Each external nullifier must be at most 29 bytes large. This function
+keccak-256-hashes a given <code>plaintext</code>, takes the last 29 bytes, and pads it
+(from the start) with 0s, and returns the resulting hex string.</p>
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