lotus-sdk/dist/lib/bitcore/taproot/musig2.js

Central repository for several classes of tools for integrating with, and building for, the Lotusia ecosystem

import { Address } from '../address.js';
import { BN, Point, Hash } from '../crypto/index.js';
import { musigKeyAgg, musigPartialSign, musigPartialSigVerify, musigTaggedHash, MUSIG_TAG_NONCE_COEFF, } from '../crypto/musig2.js';
import { buildKeyPathTaproot, buildScriptPathTaproot, calculateTapTweak, tweakPublicKey, } from '../taproot.js';
export function buildMuSigTaprootKey(signerPubKeys, state) {
    const keyAggContext = musigKeyAgg(signerPubKeys);
    const aggregatedPubKey = keyAggContext.aggregatedPubKey;
    const merkleRoot = Buffer.alloc(32);
    const tweak = calculateTapTweak(aggregatedPubKey, merkleRoot);
    const commitment = tweakPublicKey(aggregatedPubKey, merkleRoot);
    const script = buildKeyPathTaproot(aggregatedPubKey, state);
    return {
        aggregatedPubKey,
        commitment,
        script,
        keyAggContext,
        merkleRoot,
        tweak,
    };
}
export function buildMuSigTaprootKeyWithScripts(signerPubKeys, scriptTree, state) {
    const keyAggContext = musigKeyAgg(signerPubKeys);
    const aggregatedPubKey = keyAggContext.aggregatedPubKey;
    const { script, commitment, merkleRoot, leaves } = buildScriptPathTaproot(aggregatedPubKey, scriptTree, state);
    const tweak = calculateTapTweak(aggregatedPubKey, merkleRoot);
    return {
        aggregatedPubKey,
        commitment,
        script,
        keyAggContext,
        merkleRoot,
        tweak,
        leaves,
    };
}
export function signTaprootKeyPathWithMuSig2(secretNonce, privateKey, keyAggContext, signerIndex, aggregatedNonce, message, tweak) {
    const n = Point.getN();
    const commitment = keyAggContext.aggregatedPubKey.addScalar(tweak);
    const modifiedKeyAggContext = {
        ...keyAggContext,
        aggregatedPubKey: commitment,
    };
    const partialSig = musigPartialSign(secretNonce, privateKey, modifiedKeyAggContext, signerIndex, aggregatedNonce, message);
    if (signerIndex === 0) {
        const { R1, R2 } = aggregatedNonce;
        const nonceCoefData = Buffer.concat([
            commitment.toBuffer(),
            Point.pointToCompressed(R1),
            Point.pointToCompressed(R2),
            message,
        ]);
        const b = new BN(musigTaggedHash(MUSIG_TAG_NONCE_COEFF, nonceCoefData), 'be');
        const R = R1.add(R2.mul(b));
        const R_x = R.getX().toArrayLike(Buffer, 'be', 32);
        const commitment_compressed = Point.pointToCompressed(commitment.point);
        const challengeData = Buffer.concat([R_x, commitment_compressed, message]);
        const e = new BN(Hash.sha256(challengeData), 'be').umod(n);
        const tweakBN = new BN(tweak, 'be').umod(n);
        const tweakTerm = e.mul(tweakBN).umod(n);
        return partialSig.add(tweakTerm).umod(n);
    }
    return partialSig;
}
export function verifyTaprootKeyPathMuSigPartial(partialSig, publicNonce, publicKey, keyAggContext, signerIndex, aggregatedNonce, message, tweak) {
    const n = Point.getN();
    const commitment = keyAggContext.aggregatedPubKey.addScalar(tweak);
    const modifiedKeyAggContext = {
        ...keyAggContext,
        aggregatedPubKey: commitment,
    };
    let adjustedPartialSig = partialSig;
    if (signerIndex === 0) {
        const { R1, R2 } = aggregatedNonce;
        const nonceCoefData = Buffer.concat([
            commitment.toBuffer(),
            Point.pointToCompressed(R1),
            Point.pointToCompressed(R2),
            message,
        ]);
        const b = new BN(musigTaggedHash(MUSIG_TAG_NONCE_COEFF, nonceCoefData), 'be');
        const R = R1.add(R2.mul(b));
        const R_x = R.getX().toArrayLike(Buffer, 'be', 32);
        const commitment_compressed = Point.pointToCompressed(commitment.point);
        const challengeData = Buffer.concat([R_x, commitment_compressed, message]);
        const e = new BN(Hash.sha256(challengeData), 'be').umod(n);
        const tweakBN = new BN(tweak, 'be').umod(n);
        const tweakTerm = e.mul(tweakBN).umod(n);
        adjustedPartialSig = partialSig.sub(tweakTerm).umod(n);
    }
    return musigPartialSigVerify(adjustedPartialSig, publicNonce, publicKey, modifiedKeyAggContext, signerIndex, aggregatedNonce, message);
}
export function isMuSigTaprootOutput(script) {
    return script.isPayToTaproot();
}
export function createMuSigTaprootAddress(signerPubKeys, network = 'livenet', state) {
    const result = buildMuSigTaprootKey(signerPubKeys, state);
    const address = Address.fromTaprootCommitment(result.commitment, network);
    return {
        address,
        script: result.script,
        commitment: result.commitment,
        keyAggContext: result.keyAggContext,
    };
}