Proof Relayer

Generates Groth16 ZK proofs server-side. CPU-intensive — limited to 2 concurrent proof generations.

Endpoint

POST /api/proof/generate

Port: 3003
Public URL: https://relayer.specterchain.com/api/proof/generate

Request

{
  "secret": "123456789",
  "nullifierSecret": "987654321",
  "amount": "1000000000000000000",
  "blinding": "111222333",
  "tokenIdHash": "0",
  "recipient": "0xRecipientAddress",
  "withdrawAmount": "1000000000000000000",
  "newBlinding": "0"
}

Field	Type	Required	Description
secret	string	Yes	Commitment secret
nullifierSecret	string	Yes	Nullifier secret
amount	string	Yes	Full committed amount
blinding	string	Yes	Commitment blinding factor
tokenIdHash	string	Yes	Token ID hash
recipient	string	Yes	Recipient Ethereum address
withdrawAmount	string	Yes	Amount to withdraw
newBlinding	string	Yes	Blinding for change commitment ("0" for full reveal)

Response

{
  "proof": [
    "0x...", "0x...", "0x...", "0x...",
    "0x...", "0x...", "0x...", "0x..."
  ],
  "publicInputs": [
    "0x...", "0x...", "0x...", "0x...",
    "0x...", "0x...", "0x...", "0x..."
  ]
}

The proof array contains 8 uint256 values (3 EC points) ready for the reveal() function.

Limits

Parameter	Value
Rate limit	5 requests/minute/IP
Max concurrent proofs	2
Commitment cache TTL	5 minutes

Authentication

Requires HMAC signature:

X-HMAC-Signature: <computed-hmac>

Status endpoint

GET /status

Returns service status including current load and queue depth.

Security note

warning

Like the commitment relayer, this service receives your secret values in plaintext. For maximum privacy, generate proofs client-side using snarkjs. See Generating Proofs.

Internal architecture

The proof relayer:

1. Maintains an in-memory copy of the Merkle tree (rebuilt from CommitmentAdded events)
2. Computes the Merkle proof path for the requested commitment
3. Generates the Groth16 proof using snarkjs with the circuit WASM and proving key
4. Returns the formatted proof and public inputs