adding PIR project card (#346)

* adding PIR project card

data/projects.ts

@@ -54,6 +54,7 @@ import { plasmaFold } from "./projects/plasma_fold"
 import { vOPRF } from "./projects/vOPRF"
 import { mpz } from "./projects/mpz"
 import { clientSideProving } from "./projects/client-side-proving"
+import { scalingSemaphore } from "./projects/pir-scaling-semaphore"
 
 /**
  * List of Projects
@@ -61,6 +62,7 @@ import { clientSideProving } from "./projects/client-side-proving"
  * Every 'description' props supports markdown syntax https://www.markdownguide.org/basic-syntax/
  */
 export const projects: ProjectInterface[] = [
+  scalingSemaphore,
   clientSideProving,
   pse_halo2,
   sonobe,

data/projects/pir-scaling-semaphore.ts

@@ -0,0 +1,74 @@
+import { ProjectCategory, ProjectInterface, ProjectStatus } from "@/lib/types"
+
+export const scalingSemaphore: ProjectInterface = {
+  id: "scaling-semaphore-pir",
+  image: "",                    // add cover image or leave blank
+  name: "Scaling Semaphore – PIR Merkle-Path Retrieval",
+  section: "pse",
+  projectStatus: ProjectStatus.ACTIVE,
+  category: ProjectCategory.RESEARCH,
+  content: {
+    en: {
+      tldr:
+        "Private Information Retrieval lets Semaphore users fetch their Merkle path from a server without revealing which identity they own, enabling truly private proofs for groups with millions of members.",
+      description: `
+### Scaling Semaphore – Private Merkle-Path Retrieval with PIR  
+
+#### Project Overview  
+The project tackles the privacy bottleneck that appears when Semaphore groups grow to millions of members. In large groups, a user must obtain their Merkle-path (all sibling hashes from leaf to root) from a remote database before they can create a zero-knowledge membership proof. Asking for that path naïvely reveals **which identity** they own.  
+
+This project solves the problem by letting users **query the server with Private Information Retrieval (PIR)**. PIR lets a client fetch database records without the server learning which records were requested, preserving full anonymity at Internet scale.
+
+#### Why PIR matters  
+Traditional PIR protocols were too heavy for on-chain use. Recent schemes—e.g. **Respire** and Frodo-PIR—support 2²⁰ elements (≈ 1 million) with sub-second online latency and no trusted setup. By storing Merkle leaves/hashes in PIR-friendly chunks (32 B records) we can keep group trees on a server while users privately retrieve only the ~64 kB they need for a proof.
+
+#### Technical Approach  
+
+| Component | Role |
+|-----------|------|
+| **Lean Incremental Merkle Tree (LeanIMT)** | Append-only tree used by Semaphore; gives deterministic indices so the client knows exactly which nodes to fetch. |
+| **PIR Layer (Respire)** | Batched, lattice-based PIR with no offline phase; ideal for many small records. |
+| **\`lean-imt\` integration** | Rust implementation and benchmarks with Respire |
+
+**Data flow**  
+1. Client computes the indices of its Merkle path.  
+2. Client sends a PIR query for those indices to the server.  
+3. Server responds with encrypted buckets; client decrypts to obtain hashes/leaves.  
+4. Client generates the standard Semaphore ZK proof locally; nothing is leaked to the server.
+
+#### Current Status (Apr 2025)  
+- ✅ ZK-Kit LeanIMT Rust implementation  
+- 🔄 PIR proof-of-concept fetching 32-byte records from a 2²⁰-element DB  
+- 🔜 Benchmarks  
+- 🔜 Post & L&S session
+
+#### Use-cases Enabled  
+- **World-scale anonymous voting** without delegating proofs to a company server.  
+- **On-chain reputation** where users prove historical actions privately.  
+- **Privacy-preserving NFT drops** that gate by membership but hide identities.
+
+#### Resources  
+- **Project Plan:** <https://hackmd.io/@brech1/scale-semaphore-proposal>  
+- **Semaphore v4 (Rust):** <https://github.com/semaphore-protocol/semaphore-rs>  
+- **Respire PIR paper:** <https://eprint.iacr.org/2024/1165>  
+- **Customizable LeanIMT implementation:** <https://github.com/privacy-scaling-explorations/zk-kit.rust/pull/62>
+
+#### Contact  
+- **Brechy:** <mailto:brechy@pse.dev>  
+- **Discord:** <https://discord.com/invite/sF5CT5rzrR>
+      `,
+    },
+  },
+  tags: {
+    keywords: [
+      "Semaphore",
+      "PIR",
+      "LeanIMT",
+      "zero-knowledge proofs",
+      "privacy",
+      "Merkle tree",
+    ],
+    themes: ["privacy", "scalability", "identity"],
+    types: ["research", "development"],
+  },
+}