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chainsafe-bls/src/index.ts

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2019-08-05 15:48:26 +00:00
import {
BLSDomain,
BLSSecretKey,
BLSPubkey,
BLSSignature,
bytes32,
bytes8
} from "./types";
import {Keypair} from "./keypair";
import {PrivateKey} from "./privateKey";
import {G2point} from "./helpers/g2point";
import {G1point} from "./helpers/g1point";
import {PublicKey} from "./publicKey";
import {Signature} from "./signature";
import {ElipticCurvePairing} from "./helpers/ec-pairing";
import ctx from "./ctx";
/**
* Generates new secret and public key
*/
function generateKeyPair(): Keypair {
return Keypair.generate();
}
/**
* Generates public key from given secret.
* @param {BLSSecretKey} secretKey
*/
function generatePublicKey(secretKey: BLSSecretKey): BLSPubkey {
const keypair = new Keypair(PrivateKey.fromBytes(secretKey));
return keypair.publicKey.toBytesCompressed();
}
/**
* Signs given message using secret key.
* @param secretKey
* @param messageHash
* @param domain
*/
function sign(secretKey: BLSSecretKey, messageHash: bytes32, domain: BLSDomain): BLSSignature {
const privateKey = PrivateKey.fromBytes(secretKey);
const hash = G2point.hashToG2(messageHash, domain);
return privateKey.sign(hash).toBytesCompressed();
}
/**
* Compines all given signature into one.
* @param signatures
*/
function aggregateSignatures(signatures: BLSSignature[]): BLSSignature {
return signatures.map((signature): Signature => {
return Signature.fromCompressedBytes(signature)
}).reduce((previousValue, currentValue): Signature => {
return previousValue.add(currentValue);
}).toBytesCompressed();
}
/**
* Combines all given public keys into single one
* @param publicKeys
*/
function aggregatePubkeys(publicKeys: BLSPubkey[]): BLSPubkey {
if(publicKeys.length === 0) {
return new G1point(new ctx.ECP()).toBytesCompressed();
}
return publicKeys.map((publicKey): G1point => {
return G1point.fromBytesCompressed(publicKey)
}).reduce((previousValue, currentValue): G1point => {
return previousValue.add(currentValue);
}).toBytesCompressed();
}
/**
* Verifies if signature is message signed with given public key.
* @param publicKey
* @param messageHash
* @param signature
* @param domain
*/
function verify(publicKey: BLSPubkey, messageHash: bytes32, signature: BLSSignature, domain: bytes8): boolean {
try {
const key = PublicKey.fromBytes(publicKey);
const sig = Signature.fromCompressedBytes(signature);
const g1Generated = G1point.generator();
const e1 = ElipticCurvePairing.pair(key.getPoint(), G2point.hashToG2(messageHash, domain));
const e2 = ElipticCurvePairing.pair(g1Generated, sig.getPoint());
return e1.equals(e2);
} catch (e) {
return false;
}
}
/**
* Verifies if signature is list of message signed with corresponding public key.
* @param publicKeys
* @param messageHashes
* @param signature
* @param domain
*/
function verifyMultiple(publicKeys: BLSPubkey[], messageHashes: bytes32[], signature: BLSSignature, domain: bytes8): boolean {
if(publicKeys.length === 0 || publicKeys.length != messageHashes.length) {
return false;
}
try {
const g1Generated = G1point.generator();
const eCombined = new ctx.FP12(1);
publicKeys.forEach((publicKey, index): void => {
const g2 = G2point.hashToG2(messageHashes[index], domain);
eCombined.mul(
ElipticCurvePairing.pair(
PublicKey.fromBytes(publicKey).getPoint(),
g2
)
);
});
const e2 = ElipticCurvePairing.pair(g1Generated, Signature.fromCompressedBytes(signature).getPoint());
return e2.equals(eCombined);
} catch (e) {
return false;
}
}
export default {
generateKeyPair,
generatePublicKey,
sign,
aggregateSignatures,
aggregatePubkeys,
verify,
verifyMultiple
}