Circuits reference

@shh/circuits is the zk heart of the project — independent of the chain it runs on. It compiles to WASM witnesses and Groth16 zkeys, and exports Solidity verifiers.

#Layout

circuits/
├─ lib/
│  ├─ merkleProof.circom   Poseidon Merkle inclusion
│  └─ keypair.circom       pubkey + signature helpers
├─ pool/
│  └─ poolWithdraw.circom  state + association membership withdraw
└─ shielded/
   ├─ transaction.circom   generic join-split template
   └─ transaction2x2.circom  the 2-in / 2-out instantiation

#The circuits

lib/merkleProof.circom

Verifies a Poseidon Merkle inclusion proof of fixed depth LEVELS, selecting left/right by path-index bits.

lib/keypair.circom

Derives pubKey = H(privKey) and the per-note signature used to form nullifiers.

pool/poolWithdraw.circom

Proves a commitment is in both the state and association trees and binds the withdrawal parameters. See Profile B.

shielded/transaction2x2.circom

The 2-in/2-out join-split with value conservation and 248-bit range checks. See Profile A.

#The pipeline

1. 1
   Compilepnpm circuits:compile runs circom to produce .r1cs and .wasm (the witness generator).
2. 2
   Trusted setuppnpm circuits:setup runs the Powers-of-Tau and per-circuit Groth16 setup, producing .zkey proving keys and verification keys.
3. 3
   Export verifiersThe setup exports *Verifier.sol into packages/contracts/contracts/verifiers/.
4. 4
   Testpnpm circuits:test (4/4) proves a valid witness verifies and a tampered witness fails its constraints.

#Committed artifacts

Verification keys are checked in for reproducibility — keys/poolWithdraw_vkey.json and keys/transaction2x2_vkey.json — alongside circuits.config.json which declares the circuits and their parameters.