Type Definition tari_crypto::ristretto::ristretto_com_sig::RistrettoComSig

type RistrettoComSig = CommitmentSignature<RistrettoPublicKey, RistrettoSecretKey>;

A Commitment signature implementation on Ristretto

RistrettoComSig utilises the curve25519-dalek implementation of ristretto255 to provide Commitment Signature functionality utlizing Schnorr signatures.

Examples

You can create a RistrettoComSig from it’s component parts:

let r_pub = HomomorphicCommitment::from_hex("8063d85e151abee630e643e2b3dc47bfaeb8aa859c9d10d60847985f286aad19").unwrap();
let u = RistrettoSecretKey::from_bytes(b"10000000000000000000000010000000").unwrap();
let v = RistrettoSecretKey::from_bytes(b"a00000000000000000000000a0000000").unwrap();
let sig = RistrettoComSig::new(r_pub, u, v);

or you can create a signature for a commitment by signing a message with knowledge of the commitment and then verify it by calling the verify_challenge method:

let mut rng = rand::thread_rng();
let a_val = RistrettoSecretKey::random(&mut rng);
let x_val = RistrettoSecretKey::random(&mut rng);
let a_nonce = RistrettoSecretKey::random(&mut rng);
let x_nonce = RistrettoSecretKey::random(&mut rng);
let e = Blake256::digest(b"Maskerade");
let factory = PedersenCommitmentFactory::default();
let commitment = factory.commit(&x_val, &a_val);
let sig = RistrettoComSig::sign(a_val, x_val, a_nonce, x_nonce, &e, &factory).unwrap();
assert!(sig.verify_challenge(&commitment, &e, &factory));

Verifying signatures

Given a signature, (R,u,v), a commitment C and a Challenge, e, you can verify that the signature is valid by calling the verify_challenge method:

let commitment = HomomorphicCommitment::from_hex("d6cca5cc4cc302c1854a118221d6cf64d100b7da76665dae5199368f3703c665").unwrap();
let r_nonce = HomomorphicCommitment::from_hex("9607f72d84d704825864a4455c2325509ecc290eb9419bbce7ff05f1f578284c").unwrap();
let u = RistrettoSecretKey::from_hex("0fd60e6479507fec35a46d2ec9da0ae300e9202e613e99b8f2b01d7ef6eccc02").unwrap();
let v = RistrettoSecretKey::from_hex("9ae6621dd99ecc252b90a0eb69577c6f3d2e1e8abcdd43bfd0297afadf95fb0b").unwrap();
let sig = RistrettoComSig::new(r_nonce, u, v);
let e = Blake256::digest(b"Maskerade");
let factory = PedersenCommitmentFactory::default();
assert!(sig.verify_challenge(&commitment, &e, &factory));