⚡ Generate proof

CryptKeeper lets dapps outsource ZK proof generation via the Semaphore and RLN protocols. This section will review Semaphore proofs.

@src/contentscripts/injected.ts

async function semaphoreProof(
    externalNullifier: string,
    signal: string,
    circuitFilePath: string,
    zkeyFilePath: string,
    merkleProofArtifactsOrStorageAddress: string | MerkleProofArtifacts,
    merkleProof?: MerkleProof
) {

The semaphoreProof function allows the user to create a proof of a signal to be sent to the Semaphore contract. CryptKeeper uses values provided by the dapp and the private user values to generate the proof and returns it to the dapp for verification.

Your dapp should pass in public values (externalNullifier and signal).

Any circuit files (circuitFilePath and zkeyFilePath) can be used, but ready-to-use and audited circuit files can be found here and here.

Merkle witness or Merkle tree components (merkleProofArtifactsOrStorageAddress can be provided by a smart contract or as a structured input:

StorageAddress points to a Merkle tree on-chain

merkleProofArtifact is a Merkle tree in a specific format

@src/types/index.ts

export type MerkleProofArtifacts = {
    leaves: string[]
    depth: number
    leavesPerNode: number
}

SemaphoreProof requires the following arguments:

externalNullifier

a unique identifier for the signal to prevent double signaling
public input provided by dapp

signal

hash of the content of the message
public input provided by dapp

circuitFilePath

location of the circuit file
used to generate the ZK proof in the browser

zkeyFilePath

the zkeyFile contains the trusted setup [link] files and is the starting point for creating a circuit
location of the zkey file

merkleProofArtifactsOrStorageAddress

object providing Merkle witness directly (merkleProofArtifact) or the secure service address from which the Merkle witness should be obtained (merkleStorageAddress)
To generate a proof, a user must provide the Merkle path that leads to the user’s identity in the Merkle tree

RLN Proofs

RLN (Rate-Limiting Nullifier) is a ZK gadget or mechanism that enables spam prevention for anonymous environments. RLN Proofs are the same as Semaphore proofs except they generate proofs for a specific epoch (time period) and require an additional argument: rlnIdentifier.

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⚡ Generate proof

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