Noir Ring Signatures

This library provides implementations of Ring Signatures schemes in Noir. Ring Signatures are a type of cryptographic signature scheme that allow a member of a group to sign a message on behalf of the group without revealing which member actually created the signature. This provides anonymity for the signer while still proving that the signature came from a member of the specified group.

Currently, the library supports the following Ring Signature schemes:

• SAG (Signature of Anonymous Group)

Ring Signatures are over the Grumpkin curve and use the Pedersen hash function to generate the challenges.

Installation

In your Nargo.toml file, add the version of this library you would like to install under dependency:

[dependencies]
noir_ring_signatures = { tag = "v0.1.0", git = "https://github.com/zkpersona/noir-ring-signatures" }

The noir library is accompanied by a typescript library that provides a set of functions for creating Ring Signatures.

Install the Library

npm install @zkpersona/noir-ring-signatures
# or
yarn add @zkpersona/noir-ring-signatures
# or
pnpm add @zkpersona/noir-ring-signatures

Create a Ring Signature

import { generateKeyPair } from '@zkpersona/noir-ring-signatures';
import { sagToNoirInputs, sign } from '@zkpersona/noir-ring-signatures/sag';

import { generateToml, toCircuitInputs } from '@zkpersona/noir-helpers';

import { Fr } from '@aztec/aztec.js';
import { pedersenHashBuffer } from '@aztec/foundation/crypto';

const message = new TextEncoder().encode('Confidential message');
const hashedMessage = await pedersenHashBuffer(Buffer.from(message));
const messageFr = Fr.fromBuffer(hashedMessage);

const ringSize = 16;
const signerIndex = 3;

const kps = Array.from({ length: 16 }, generateKeyPair);
const keyPairs = await Promise.all(kps);
const publicKeys = keyPairs.map((kp) => kp.publicKey);

const signature = await sign(
  messageFr,
  publicKeys,
  keyPairs[signerIndex]!.privateKey,
  signerIndex
);

const inputs = sagToNoirInputs(signature, messageFr, ringSize);

// To convert the inputs to a circuit input format, use the following function:
const circuitInputs = toCircuitInputs(inputs);

// To Generate a TOML file for the circuit inputs, use the following command:
generateToml(circuitInputs, '/abs/path/to/file.toml');

Noir Circuit

use noir_ring_signatures::sag::{Signature, verify};
use std::embedded_curve_ops::EmbeddedCurvePoint;

pub global MAX_RING_SIZE: u32 = 16;

pub fn main(
    signature: Signature<MAX_RING_SIZE>,
    hashed_message: Field,
    ring: BoundedVec<EmbeddedCurvePoint, MAX_RING_SIZE>,
) -> pub bool {
    verify(signature, hashed_message, ring)
}

Benchmarks

Benchmarks are generated using the scripts/build-gates-report.sh script. The benchmark will be generated at ./gates_report.json.

1. Small Ring SAG (Ring Size=8)

   • ACIR opcodes: 1019
   • Circuit size: 23530

2. Medium Ring SAG (Ring Size=32)

   • ACIR opcodes: 5555
   • Circuit size: 92148

3. Large Ring SAG (Ring Size=128)

   • ACIR opcodes: 46739
   • Circuit size: 464540

To generate the benchmarks, run the following command:

noir export && bash ./scripts/build-gates-report.sh

License

This project is licensed under the MIT License. See the LICENSE file for more details.

Contributing

Contributions are welcome! Open an issue or submit a pull request.