288 lines
12 KiB
JavaScript
288 lines
12 KiB
JavaScript
"use strict";
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Object.defineProperty(exports, "__esModule", { value: true });
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exports.bls = bls;
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const modular_js_1 = require("./modular.js");
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const utils_js_1 = require("./utils.js");
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// prettier-ignore
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const hash_to_curve_js_1 = require("./hash-to-curve.js");
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const weierstrass_js_1 = require("./weierstrass.js");
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// prettier-ignore
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const _2n = BigInt(2), _3n = BigInt(3);
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function bls(CURVE) {
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// Fields are specific for curve, so for now we'll need to pass them with opts
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const { Fp, Fr, Fp2, Fp6, Fp12 } = CURVE.fields;
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const BLS_X_LEN = (0, utils_js_1.bitLen)(CURVE.params.x);
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// Pre-compute coefficients for sparse multiplication
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// Point addition and point double calculations is reused for coefficients
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function calcPairingPrecomputes(p) {
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const { x, y } = p;
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// prettier-ignore
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const Qx = x, Qy = y, Qz = Fp2.ONE;
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// prettier-ignore
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let Rx = Qx, Ry = Qy, Rz = Qz;
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let ell_coeff = [];
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for (let i = BLS_X_LEN - 2; i >= 0; i--) {
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// Double
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let t0 = Fp2.sqr(Ry); // Ry²
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let t1 = Fp2.sqr(Rz); // Rz²
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let t2 = Fp2.multiplyByB(Fp2.mul(t1, _3n)); // 3 * T1 * B
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let t3 = Fp2.mul(t2, _3n); // 3 * T2
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let t4 = Fp2.sub(Fp2.sub(Fp2.sqr(Fp2.add(Ry, Rz)), t1), t0); // (Ry + Rz)² - T1 - T0
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ell_coeff.push([
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Fp2.sub(t2, t0), // T2 - T0
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Fp2.mul(Fp2.sqr(Rx), _3n), // 3 * Rx²
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Fp2.neg(t4), // -T4
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]);
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Rx = Fp2.div(Fp2.mul(Fp2.mul(Fp2.sub(t0, t3), Rx), Ry), _2n); // ((T0 - T3) * Rx * Ry) / 2
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Ry = Fp2.sub(Fp2.sqr(Fp2.div(Fp2.add(t0, t3), _2n)), Fp2.mul(Fp2.sqr(t2), _3n)); // ((T0 + T3) / 2)² - 3 * T2²
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Rz = Fp2.mul(t0, t4); // T0 * T4
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if ((0, utils_js_1.bitGet)(CURVE.params.x, i)) {
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// Addition
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let t0 = Fp2.sub(Ry, Fp2.mul(Qy, Rz)); // Ry - Qy * Rz
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let t1 = Fp2.sub(Rx, Fp2.mul(Qx, Rz)); // Rx - Qx * Rz
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ell_coeff.push([
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Fp2.sub(Fp2.mul(t0, Qx), Fp2.mul(t1, Qy)), // T0 * Qx - T1 * Qy
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Fp2.neg(t0), // -T0
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t1, // T1
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]);
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let t2 = Fp2.sqr(t1); // T1²
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let t3 = Fp2.mul(t2, t1); // T2 * T1
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let t4 = Fp2.mul(t2, Rx); // T2 * Rx
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let t5 = Fp2.add(Fp2.sub(t3, Fp2.mul(t4, _2n)), Fp2.mul(Fp2.sqr(t0), Rz)); // T3 - 2 * T4 + T0² * Rz
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Rx = Fp2.mul(t1, t5); // T1 * T5
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Ry = Fp2.sub(Fp2.mul(Fp2.sub(t4, t5), t0), Fp2.mul(t3, Ry)); // (T4 - T5) * T0 - T3 * Ry
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Rz = Fp2.mul(Rz, t3); // Rz * T3
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}
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}
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return ell_coeff;
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}
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function millerLoop(ell, g1) {
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const { x } = CURVE.params;
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const Px = g1[0];
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const Py = g1[1];
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let f12 = Fp12.ONE;
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for (let j = 0, i = BLS_X_LEN - 2; i >= 0; i--, j++) {
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const E = ell[j];
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f12 = Fp12.multiplyBy014(f12, E[0], Fp2.mul(E[1], Px), Fp2.mul(E[2], Py));
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if ((0, utils_js_1.bitGet)(x, i)) {
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j += 1;
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const F = ell[j];
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f12 = Fp12.multiplyBy014(f12, F[0], Fp2.mul(F[1], Px), Fp2.mul(F[2], Py));
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}
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if (i !== 0)
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f12 = Fp12.sqr(f12);
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}
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return Fp12.conjugate(f12);
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}
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const utils = {
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randomPrivateKey: () => {
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const length = (0, modular_js_1.getMinHashLength)(Fr.ORDER);
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return (0, modular_js_1.mapHashToField)(CURVE.randomBytes(length), Fr.ORDER);
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},
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calcPairingPrecomputes,
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};
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// Point on G1 curve: (x, y)
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const G1_ = (0, weierstrass_js_1.weierstrassPoints)({ n: Fr.ORDER, ...CURVE.G1 });
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const G1 = Object.assign(G1_, (0, hash_to_curve_js_1.createHasher)(G1_.ProjectivePoint, CURVE.G1.mapToCurve, {
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...CURVE.htfDefaults,
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...CURVE.G1.htfDefaults,
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}));
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function pairingPrecomputes(point) {
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const p = point;
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if (p._PPRECOMPUTES)
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return p._PPRECOMPUTES;
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p._PPRECOMPUTES = calcPairingPrecomputes(point.toAffine());
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return p._PPRECOMPUTES;
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}
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// TODO: export
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// function clearPairingPrecomputes(point: G2) {
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// const p = point as G2 & withPairingPrecomputes;
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// p._PPRECOMPUTES = undefined;
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// }
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// Point on G2 curve (complex numbers): (x₁, x₂+i), (y₁, y₂+i)
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const G2_ = (0, weierstrass_js_1.weierstrassPoints)({ n: Fr.ORDER, ...CURVE.G2 });
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const G2 = Object.assign(G2_, (0, hash_to_curve_js_1.createHasher)(G2_.ProjectivePoint, CURVE.G2.mapToCurve, {
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...CURVE.htfDefaults,
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...CURVE.G2.htfDefaults,
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}));
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const { ShortSignature } = CURVE.G1;
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const { Signature } = CURVE.G2;
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// Calculates bilinear pairing
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function pairing(Q, P, withFinalExponent = true) {
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if (Q.equals(G1.ProjectivePoint.ZERO) || P.equals(G2.ProjectivePoint.ZERO))
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throw new Error('pairing is not available for ZERO point');
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Q.assertValidity();
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P.assertValidity();
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// Performance: 9ms for millerLoop and ~14ms for exp.
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const Qa = Q.toAffine();
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const looped = millerLoop(pairingPrecomputes(P), [Qa.x, Qa.y]);
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return withFinalExponent ? Fp12.finalExponentiate(looped) : looped;
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}
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function normP1(point) {
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return point instanceof G1.ProjectivePoint ? point : G1.ProjectivePoint.fromHex(point);
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}
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function normP1Hash(point, htfOpts) {
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return point instanceof G1.ProjectivePoint
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? point
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: G1.hashToCurve((0, utils_js_1.ensureBytes)('point', point), htfOpts);
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}
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function normP2(point) {
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return point instanceof G2.ProjectivePoint ? point : Signature.fromHex(point);
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}
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function normP2Hash(point, htfOpts) {
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return point instanceof G2.ProjectivePoint
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? point
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: G2.hashToCurve((0, utils_js_1.ensureBytes)('point', point), htfOpts);
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}
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// Multiplies generator (G1) by private key.
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// P = pk x G
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function getPublicKey(privateKey) {
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return G1.ProjectivePoint.fromPrivateKey(privateKey).toRawBytes(true);
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}
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// Multiplies generator (G2) by private key.
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// P = pk x G
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function getPublicKeyForShortSignatures(privateKey) {
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return G2.ProjectivePoint.fromPrivateKey(privateKey).toRawBytes(true);
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}
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function sign(message, privateKey, htfOpts) {
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const msgPoint = normP2Hash(message, htfOpts);
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msgPoint.assertValidity();
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const sigPoint = msgPoint.multiply(G1.normPrivateKeyToScalar(privateKey));
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if (message instanceof G2.ProjectivePoint)
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return sigPoint;
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return Signature.toRawBytes(sigPoint);
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}
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function signShortSignature(message, privateKey, htfOpts) {
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const msgPoint = normP1Hash(message, htfOpts);
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msgPoint.assertValidity();
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const sigPoint = msgPoint.multiply(G1.normPrivateKeyToScalar(privateKey));
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if (message instanceof G1.ProjectivePoint)
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return sigPoint;
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return ShortSignature.toRawBytes(sigPoint);
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}
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// Checks if pairing of public key & hash is equal to pairing of generator & signature.
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// e(P, H(m)) == e(G, S)
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function verify(signature, message, publicKey, htfOpts) {
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const P = normP1(publicKey);
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const Hm = normP2Hash(message, htfOpts);
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const G = G1.ProjectivePoint.BASE;
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const S = normP2(signature);
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// Instead of doing 2 exponentiations, we use property of billinear maps
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// and do one exp after multiplying 2 points.
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const ePHm = pairing(P.negate(), Hm, false);
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const eGS = pairing(G, S, false);
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const exp = Fp12.finalExponentiate(Fp12.mul(eGS, ePHm));
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return Fp12.eql(exp, Fp12.ONE);
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}
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// Checks if pairing of public key & hash is equal to pairing of generator & signature.
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// e(S, G) == e(H(m), P)
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function verifyShortSignature(signature, message, publicKey, htfOpts) {
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const P = normP2(publicKey);
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const Hm = normP1Hash(message, htfOpts);
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const G = G2.ProjectivePoint.BASE;
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const S = normP1(signature);
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// Instead of doing 2 exponentiations, we use property of billinear maps
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// and do one exp after multiplying 2 points.
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const eHmP = pairing(Hm, P, false);
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const eSG = pairing(S, G.negate(), false);
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const exp = Fp12.finalExponentiate(Fp12.mul(eSG, eHmP));
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return Fp12.eql(exp, Fp12.ONE);
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}
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function aggregatePublicKeys(publicKeys) {
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if (!publicKeys.length)
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throw new Error('Expected non-empty array');
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const agg = publicKeys.map(normP1).reduce((sum, p) => sum.add(p), G1.ProjectivePoint.ZERO);
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const aggAffine = agg; //.toAffine();
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if (publicKeys[0] instanceof G1.ProjectivePoint) {
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aggAffine.assertValidity();
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return aggAffine;
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}
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// toRawBytes ensures point validity
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return aggAffine.toRawBytes(true);
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}
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function aggregateSignatures(signatures) {
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if (!signatures.length)
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throw new Error('Expected non-empty array');
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const agg = signatures.map(normP2).reduce((sum, s) => sum.add(s), G2.ProjectivePoint.ZERO);
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const aggAffine = agg; //.toAffine();
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if (signatures[0] instanceof G2.ProjectivePoint) {
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aggAffine.assertValidity();
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return aggAffine;
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}
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return Signature.toRawBytes(aggAffine);
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}
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function aggregateShortSignatures(signatures) {
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if (!signatures.length)
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throw new Error('Expected non-empty array');
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const agg = signatures.map(normP1).reduce((sum, s) => sum.add(s), G1.ProjectivePoint.ZERO);
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const aggAffine = agg; //.toAffine();
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if (signatures[0] instanceof G1.ProjectivePoint) {
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aggAffine.assertValidity();
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return aggAffine;
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}
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return ShortSignature.toRawBytes(aggAffine);
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}
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// https://ethresear.ch/t/fast-verification-of-multiple-bls-signatures/5407
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// e(G, S) = e(G, SUM(n)(Si)) = MUL(n)(e(G, Si))
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function verifyBatch(signature, messages, publicKeys, htfOpts) {
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// @ts-ignore
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// console.log('verifyBatch', bytesToHex(signature as any), messages, publicKeys.map(bytesToHex));
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if (!messages.length)
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throw new Error('Expected non-empty messages array');
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if (publicKeys.length !== messages.length)
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throw new Error('Pubkey count should equal msg count');
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const sig = normP2(signature);
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const nMessages = messages.map((i) => normP2Hash(i, htfOpts));
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const nPublicKeys = publicKeys.map(normP1);
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try {
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const paired = [];
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for (const message of new Set(nMessages)) {
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const groupPublicKey = nMessages.reduce((groupPublicKey, subMessage, i) => subMessage === message ? groupPublicKey.add(nPublicKeys[i]) : groupPublicKey, G1.ProjectivePoint.ZERO);
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// const msg = message instanceof PointG2 ? message : await PointG2.hashToCurve(message);
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// Possible to batch pairing for same msg with different groupPublicKey here
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paired.push(pairing(groupPublicKey, message, false));
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}
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paired.push(pairing(G1.ProjectivePoint.BASE.negate(), sig, false));
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const product = paired.reduce((a, b) => Fp12.mul(a, b), Fp12.ONE);
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const exp = Fp12.finalExponentiate(product);
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return Fp12.eql(exp, Fp12.ONE);
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}
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catch {
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return false;
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}
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}
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G1.ProjectivePoint.BASE._setWindowSize(4);
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return {
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getPublicKey,
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getPublicKeyForShortSignatures,
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sign,
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signShortSignature,
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verify,
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verifyBatch,
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verifyShortSignature,
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aggregatePublicKeys,
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aggregateSignatures,
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aggregateShortSignatures,
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millerLoop,
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pairing,
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G1,
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G2,
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Signature,
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ShortSignature,
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fields: {
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Fr,
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Fp,
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Fp2,
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Fp6,
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Fp12,
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},
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params: {
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x: CURVE.params.x,
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r: CURVE.params.r,
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G1b: CURVE.G1.b,
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G2b: CURVE.G2.b,
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},
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utils,
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};
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}
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//# sourceMappingURL=bls.js.map
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