lotus-sdk/dist/lib/p2p/musig2/election.js

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

import { sha256 } from '@noble/hashes/sha256';
import { bytesToHex } from '@noble/hashes/utils';
export var ElectionMethod;
(function (ElectionMethod) {
    ElectionMethod["LEXICOGRAPHIC"] = "lexicographic";
    ElectionMethod["HASH_BASED"] = "hash-based";
    ElectionMethod["FIRST_SIGNER"] = "first-signer";
    ElectionMethod["LAST_SIGNER"] = "last-signer";
})(ElectionMethod || (ElectionMethod = {}));
export function electCoordinator(signers, method = ElectionMethod.LEXICOGRAPHIC) {
    if (signers.length === 0) {
        throw new Error('Cannot elect coordinator: no signers provided');
    }
    if (signers.length === 1) {
        return {
            coordinatorIndex: 0,
            coordinatorPublicKey: signers[0],
            sortedSigners: [signers[0]],
            indexMapping: new Map([[0, 0]]),
            electionProof: computeElectionProof(signers),
        };
    }
    switch (method) {
        case ElectionMethod.LEXICOGRAPHIC:
            return electByLexicographic(signers);
        case ElectionMethod.HASH_BASED:
            return electByHash(signers);
        case ElectionMethod.FIRST_SIGNER:
            return electFirstSigner(signers);
        case ElectionMethod.LAST_SIGNER:
            return electLastSigner(signers);
        default:
            throw new Error(`Unknown election method: ${method}`);
    }
}
function electByLexicographic(signers) {
    const indexed = signers.map((pk, idx) => ({
        originalIndex: idx,
        publicKey: pk,
        buffer: pk.toBuffer(),
    }));
    indexed.sort((a, b) => a.buffer.compare(b.buffer));
    const coordinator = indexed[0];
    const sortedSigners = indexed.map(item => item.publicKey);
    const indexMapping = new Map();
    indexed.forEach((item, sortedIdx) => {
        indexMapping.set(item.originalIndex, sortedIdx);
    });
    return {
        coordinatorIndex: 0,
        coordinatorPublicKey: coordinator.publicKey,
        sortedSigners,
        indexMapping,
        electionProof: computeElectionProof(signers),
    };
}
function electByHash(signers) {
    const indexed = signers.map((pk, idx) => ({
        originalIndex: idx,
        publicKey: pk,
        buffer: pk.toBuffer(),
    }));
    indexed.sort((a, b) => a.buffer.compare(b.buffer));
    const sortedSigners = indexed.map(item => item.publicKey);
    const indexMapping = new Map();
    indexed.forEach((item, sortedIdx) => {
        indexMapping.set(item.originalIndex, sortedIdx);
    });
    const concatenated = sortedSigners.map(pk => pk.toString()).join('');
    const hash = Buffer.from(sha256(new TextEncoder().encode(concatenated)));
    const hashValue = hash.readUInt32BE(0);
    const coordinatorIndex = hashValue % sortedSigners.length;
    return {
        coordinatorIndex,
        coordinatorPublicKey: sortedSigners[coordinatorIndex],
        sortedSigners,
        indexMapping,
        electionProof: computeElectionProof(signers),
    };
}
function electFirstSigner(signers) {
    const indexed = signers.map((pk, idx) => ({
        originalIndex: idx,
        publicKey: pk,
        buffer: pk.toBuffer(),
    }));
    indexed.sort((a, b) => a.buffer.compare(b.buffer));
    const sortedSigners = indexed.map(item => item.publicKey);
    const indexMapping = new Map();
    indexed.forEach((item, sortedIdx) => {
        indexMapping.set(item.originalIndex, sortedIdx);
    });
    return {
        coordinatorIndex: 0,
        coordinatorPublicKey: sortedSigners[0],
        sortedSigners,
        indexMapping,
        electionProof: computeElectionProof(signers),
    };
}
function electLastSigner(signers) {
    const indexed = signers.map((pk, idx) => ({
        originalIndex: idx,
        publicKey: pk,
        buffer: pk.toBuffer(),
    }));
    indexed.sort((a, b) => a.buffer.compare(b.buffer));
    const sortedSigners = indexed.map(item => item.publicKey);
    const coordinatorIndex = sortedSigners.length - 1;
    const indexMapping = new Map();
    indexed.forEach((item, sortedIdx) => {
        indexMapping.set(item.originalIndex, sortedIdx);
    });
    return {
        coordinatorIndex,
        coordinatorPublicKey: sortedSigners[coordinatorIndex],
        sortedSigners,
        indexMapping,
        electionProof: computeElectionProof(signers),
    };
}
function computeElectionProof(signers) {
    const concatenated = signers
        .map(pk => pk.toString())
        .sort()
        .join('');
    return bytesToHex(sha256(new TextEncoder().encode(concatenated)));
}
export function verifyElectionResult(signers, result, method = ElectionMethod.LEXICOGRAPHIC) {
    const expectedResult = electCoordinator(signers, method);
    return (expectedResult.coordinatorIndex === result.coordinatorIndex &&
        expectedResult.electionProof === result.electionProof);
}
export function isCoordinator(signers, signerIndex, method = ElectionMethod.LEXICOGRAPHIC) {
    if (signerIndex < 0 || signerIndex >= signers.length) {
        return false;
    }
    const election = electCoordinator(signers, method);
    return election.coordinatorIndex === signerIndex;
}
export function getCoordinatorPublicKey(signers, method = ElectionMethod.LEXICOGRAPHIC) {
    const election = electCoordinator(signers, method);
    return election.coordinatorPublicKey;
}
export function getBackupCoordinator(signers, currentCoordinatorIndex, method = ElectionMethod.LEXICOGRAPHIC) {
    if (signers.length === 1) {
        return null;
    }
    switch (method) {
        case ElectionMethod.LEXICOGRAPHIC:
            return getBackupForLexicographic(signers, currentCoordinatorIndex);
        case ElectionMethod.HASH_BASED:
            return getBackupForHashBased(signers, currentCoordinatorIndex);
        case ElectionMethod.FIRST_SIGNER:
            return getBackupForFirstSigner(signers, currentCoordinatorIndex);
        case ElectionMethod.LAST_SIGNER:
            return getBackupForLastSigner(signers, currentCoordinatorIndex);
        default:
            throw new Error(`Unknown election method: ${method}`);
    }
}
function getBackupForLexicographic(signers, currentCoordinatorIndex) {
    const indexed = signers.map((pk, idx) => ({
        originalIndex: idx,
        publicKey: pk,
        hex: pk.toString(),
    }));
    indexed.sort((a, b) => a.hex.localeCompare(b.hex));
    const currentSortedIndex = indexed.findIndex(item => item.originalIndex === currentCoordinatorIndex);
    if (currentSortedIndex === -1) {
        throw new Error('Current coordinator not found in signers list');
    }
    const nextSortedIndex = (currentSortedIndex + 1) % indexed.length;
    return indexed[nextSortedIndex].originalIndex;
}
function getBackupForHashBased(signers, currentCoordinatorIndex) {
    return (currentCoordinatorIndex + 1) % signers.length;
}
function getBackupForFirstSigner(signers, currentCoordinatorIndex) {
    const nextIndex = currentCoordinatorIndex + 1;
    if (nextIndex >= signers.length) {
        return null;
    }
    return nextIndex;
}
function getBackupForLastSigner(signers, currentCoordinatorIndex) {
    const nextIndex = currentCoordinatorIndex - 1;
    if (nextIndex < 0) {
        return null;
    }
    return nextIndex;
}
export function getCoordinatorPriorityList(signers, method = ElectionMethod.LEXICOGRAPHIC) {
    const election = electCoordinator(signers, method);
    const priorityList = [election.coordinatorIndex];
    let currentIndex = election.coordinatorIndex;
    while (true) {
        const backup = getBackupCoordinator(signers, currentIndex, method);
        if (backup === null || priorityList.includes(backup)) {
            break;
        }
        priorityList.push(backup);
        currentIndex = backup;
    }
    return priorityList;
}