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- "use strict";
- Object.defineProperty(exports, "__esModule", { value: true });
- exports.encodeToCurve = exports.hashToCurve = exports.schnorr = exports.secp256k1 = void 0;
- /*! noble-curves - MIT License (c) 2022 Paul Miller (paulmillr.com) */
- const sha256_1 = require("@noble/hashes/sha256");
- const utils_1 = require("@noble/hashes/utils");
- const _shortw_utils_js_1 = require("./_shortw_utils.js");
- const hash_to_curve_js_1 = require("./abstract/hash-to-curve.js");
- const modular_js_1 = require("./abstract/modular.js");
- const utils_js_1 = require("./abstract/utils.js");
- const weierstrass_js_1 = require("./abstract/weierstrass.js");
- const secp256k1P = BigInt('0xfffffffffffffffffffffffffffffffffffffffffffffffffffffffefffffc2f');
- const secp256k1N = BigInt('0xfffffffffffffffffffffffffffffffebaaedce6af48a03bbfd25e8cd0364141');
- const _1n = BigInt(1);
- const _2n = BigInt(2);
- const divNearest = (a, b) => (a + b / _2n) / b;
- /**
- * √n = n^((p+1)/4) for fields p = 3 mod 4. We unwrap the loop and multiply bit-by-bit.
- * (P+1n/4n).toString(2) would produce bits [223x 1, 0, 22x 1, 4x 0, 11, 00]
- */
- function sqrtMod(y) {
- const P = secp256k1P;
- // prettier-ignore
- const _3n = BigInt(3), _6n = BigInt(6), _11n = BigInt(11), _22n = BigInt(22);
- // prettier-ignore
- const _23n = BigInt(23), _44n = BigInt(44), _88n = BigInt(88);
- const b2 = (y * y * y) % P; // x^3, 11
- const b3 = (b2 * b2 * y) % P; // x^7
- const b6 = ((0, modular_js_1.pow2)(b3, _3n, P) * b3) % P;
- const b9 = ((0, modular_js_1.pow2)(b6, _3n, P) * b3) % P;
- const b11 = ((0, modular_js_1.pow2)(b9, _2n, P) * b2) % P;
- const b22 = ((0, modular_js_1.pow2)(b11, _11n, P) * b11) % P;
- const b44 = ((0, modular_js_1.pow2)(b22, _22n, P) * b22) % P;
- const b88 = ((0, modular_js_1.pow2)(b44, _44n, P) * b44) % P;
- const b176 = ((0, modular_js_1.pow2)(b88, _88n, P) * b88) % P;
- const b220 = ((0, modular_js_1.pow2)(b176, _44n, P) * b44) % P;
- const b223 = ((0, modular_js_1.pow2)(b220, _3n, P) * b3) % P;
- const t1 = ((0, modular_js_1.pow2)(b223, _23n, P) * b22) % P;
- const t2 = ((0, modular_js_1.pow2)(t1, _6n, P) * b2) % P;
- const root = (0, modular_js_1.pow2)(t2, _2n, P);
- if (!Fp.eql(Fp.sqr(root), y))
- throw new Error('Cannot find square root');
- return root;
- }
- const Fp = (0, modular_js_1.Field)(secp256k1P, undefined, undefined, { sqrt: sqrtMod });
- exports.secp256k1 = (0, _shortw_utils_js_1.createCurve)({
- a: BigInt(0), // equation params: a, b
- b: BigInt(7), // Seem to be rigid: bitcointalk.org/index.php?topic=289795.msg3183975#msg3183975
- Fp, // Field's prime: 2n**256n - 2n**32n - 2n**9n - 2n**8n - 2n**7n - 2n**6n - 2n**4n - 1n
- n: secp256k1N, // Curve order, total count of valid points in the field
- // Base point (x, y) aka generator point
- Gx: BigInt('55066263022277343669578718895168534326250603453777594175500187360389116729240'),
- Gy: BigInt('32670510020758816978083085130507043184471273380659243275938904335757337482424'),
- h: BigInt(1), // Cofactor
- lowS: true, // Allow only low-S signatures by default in sign() and verify()
- /**
- * secp256k1 belongs to Koblitz curves: it has efficiently computable endomorphism.
- * Endomorphism uses 2x less RAM, speeds up precomputation by 2x and ECDH / key recovery by 20%.
- * For precomputed wNAF it trades off 1/2 init time & 1/3 ram for 20% perf hit.
- * Explanation: https://gist.github.com/paulmillr/eb670806793e84df628a7c434a873066
- */
- endo: {
- beta: BigInt('0x7ae96a2b657c07106e64479eac3434e99cf0497512f58995c1396c28719501ee'),
- splitScalar: (k) => {
- const n = secp256k1N;
- const a1 = BigInt('0x3086d221a7d46bcde86c90e49284eb15');
- const b1 = -_1n * BigInt('0xe4437ed6010e88286f547fa90abfe4c3');
- const a2 = BigInt('0x114ca50f7a8e2f3f657c1108d9d44cfd8');
- const b2 = a1;
- const POW_2_128 = BigInt('0x100000000000000000000000000000000'); // (2n**128n).toString(16)
- const c1 = divNearest(b2 * k, n);
- const c2 = divNearest(-b1 * k, n);
- let k1 = (0, modular_js_1.mod)(k - c1 * a1 - c2 * a2, n);
- let k2 = (0, modular_js_1.mod)(-c1 * b1 - c2 * b2, n);
- const k1neg = k1 > POW_2_128;
- const k2neg = k2 > POW_2_128;
- if (k1neg)
- k1 = n - k1;
- if (k2neg)
- k2 = n - k2;
- if (k1 > POW_2_128 || k2 > POW_2_128) {
- throw new Error('splitScalar: Endomorphism failed, k=' + k);
- }
- return { k1neg, k1, k2neg, k2 };
- },
- },
- }, sha256_1.sha256);
- // Schnorr signatures are superior to ECDSA from above. Below is Schnorr-specific BIP0340 code.
- // https://github.com/bitcoin/bips/blob/master/bip-0340.mediawiki
- const _0n = BigInt(0);
- const fe = (x) => typeof x === 'bigint' && _0n < x && x < secp256k1P;
- const ge = (x) => typeof x === 'bigint' && _0n < x && x < secp256k1N;
- /** An object mapping tags to their tagged hash prefix of [SHA256(tag) | SHA256(tag)] */
- const TAGGED_HASH_PREFIXES = {};
- function taggedHash(tag, ...messages) {
- let tagP = TAGGED_HASH_PREFIXES[tag];
- if (tagP === undefined) {
- const tagH = (0, sha256_1.sha256)(Uint8Array.from(tag, (c) => c.charCodeAt(0)));
- tagP = (0, utils_js_1.concatBytes)(tagH, tagH);
- TAGGED_HASH_PREFIXES[tag] = tagP;
- }
- return (0, sha256_1.sha256)((0, utils_js_1.concatBytes)(tagP, ...messages));
- }
- // ECDSA compact points are 33-byte. Schnorr is 32: we strip first byte 0x02 or 0x03
- const pointToBytes = (point) => point.toRawBytes(true).slice(1);
- const numTo32b = (n) => (0, utils_js_1.numberToBytesBE)(n, 32);
- const modP = (x) => (0, modular_js_1.mod)(x, secp256k1P);
- const modN = (x) => (0, modular_js_1.mod)(x, secp256k1N);
- const Point = exports.secp256k1.ProjectivePoint;
- const GmulAdd = (Q, a, b) => Point.BASE.multiplyAndAddUnsafe(Q, a, b);
- // Calculate point, scalar and bytes
- function schnorrGetExtPubKey(priv) {
- let d_ = exports.secp256k1.utils.normPrivateKeyToScalar(priv); // same method executed in fromPrivateKey
- let p = Point.fromPrivateKey(d_); // P = d'⋅G; 0 < d' < n check is done inside
- const scalar = p.hasEvenY() ? d_ : modN(-d_);
- return { scalar: scalar, bytes: pointToBytes(p) };
- }
- /**
- * lift_x from BIP340. Convert 32-byte x coordinate to elliptic curve point.
- * @returns valid point checked for being on-curve
- */
- function lift_x(x) {
- if (!fe(x))
- throw new Error('bad x: need 0 < x < p'); // Fail if x ≥ p.
- const xx = modP(x * x);
- const c = modP(xx * x + BigInt(7)); // Let c = x³ + 7 mod p.
- let y = sqrtMod(c); // Let y = c^(p+1)/4 mod p.
- if (y % _2n !== _0n)
- y = modP(-y); // Return the unique point P such that x(P) = x and
- const p = new Point(x, y, _1n); // y(P) = y if y mod 2 = 0 or y(P) = p-y otherwise.
- p.assertValidity();
- return p;
- }
- /**
- * Create tagged hash, convert it to bigint, reduce modulo-n.
- */
- function challenge(...args) {
- return modN((0, utils_js_1.bytesToNumberBE)(taggedHash('BIP0340/challenge', ...args)));
- }
- /**
- * Schnorr public key is just `x` coordinate of Point as per BIP340.
- */
- function schnorrGetPublicKey(privateKey) {
- return schnorrGetExtPubKey(privateKey).bytes; // d'=int(sk). Fail if d'=0 or d'≥n. Ret bytes(d'⋅G)
- }
- /**
- * Creates Schnorr signature as per BIP340. Verifies itself before returning anything.
- * auxRand is optional and is not the sole source of k generation: bad CSPRNG won't be dangerous.
- */
- function schnorrSign(message, privateKey, auxRand = (0, utils_1.randomBytes)(32)) {
- const m = (0, utils_js_1.ensureBytes)('message', message);
- const { bytes: px, scalar: d } = schnorrGetExtPubKey(privateKey); // checks for isWithinCurveOrder
- const a = (0, utils_js_1.ensureBytes)('auxRand', auxRand, 32); // Auxiliary random data a: a 32-byte array
- const t = numTo32b(d ^ (0, utils_js_1.bytesToNumberBE)(taggedHash('BIP0340/aux', a))); // Let t be the byte-wise xor of bytes(d) and hash/aux(a)
- const rand = taggedHash('BIP0340/nonce', t, px, m); // Let rand = hash/nonce(t || bytes(P) || m)
- const k_ = modN((0, utils_js_1.bytesToNumberBE)(rand)); // Let k' = int(rand) mod n
- if (k_ === _0n)
- throw new Error('sign failed: k is zero'); // Fail if k' = 0.
- const { bytes: rx, scalar: k } = schnorrGetExtPubKey(k_); // Let R = k'⋅G.
- const e = challenge(rx, px, m); // Let e = int(hash/challenge(bytes(R) || bytes(P) || m)) mod n.
- const sig = new Uint8Array(64); // Let sig = bytes(R) || bytes((k + ed) mod n).
- sig.set(rx, 0);
- sig.set(numTo32b(modN(k + e * d)), 32);
- // If Verify(bytes(P), m, sig) (see below) returns failure, abort
- if (!schnorrVerify(sig, m, px))
- throw new Error('sign: Invalid signature produced');
- return sig;
- }
- /**
- * Verifies Schnorr signature.
- * Will swallow errors & return false except for initial type validation of arguments.
- */
- function schnorrVerify(signature, message, publicKey) {
- const sig = (0, utils_js_1.ensureBytes)('signature', signature, 64);
- const m = (0, utils_js_1.ensureBytes)('message', message);
- const pub = (0, utils_js_1.ensureBytes)('publicKey', publicKey, 32);
- try {
- const P = lift_x((0, utils_js_1.bytesToNumberBE)(pub)); // P = lift_x(int(pk)); fail if that fails
- const r = (0, utils_js_1.bytesToNumberBE)(sig.subarray(0, 32)); // Let r = int(sig[0:32]); fail if r ≥ p.
- if (!fe(r))
- return false;
- const s = (0, utils_js_1.bytesToNumberBE)(sig.subarray(32, 64)); // Let s = int(sig[32:64]); fail if s ≥ n.
- if (!ge(s))
- return false;
- const e = challenge(numTo32b(r), pointToBytes(P), m); // int(challenge(bytes(r)||bytes(P)||m))%n
- const R = GmulAdd(P, s, modN(-e)); // R = s⋅G - e⋅P
- if (!R || !R.hasEvenY() || R.toAffine().x !== r)
- return false; // -eP == (n-e)P
- return true; // Fail if is_infinite(R) / not has_even_y(R) / x(R) ≠ r.
- }
- catch (error) {
- return false;
- }
- }
- exports.schnorr = (() => ({
- getPublicKey: schnorrGetPublicKey,
- sign: schnorrSign,
- verify: schnorrVerify,
- utils: {
- randomPrivateKey: exports.secp256k1.utils.randomPrivateKey,
- lift_x,
- pointToBytes,
- numberToBytesBE: utils_js_1.numberToBytesBE,
- bytesToNumberBE: utils_js_1.bytesToNumberBE,
- taggedHash,
- mod: modular_js_1.mod,
- },
- }))();
- const isoMap = /* @__PURE__ */ (() => (0, hash_to_curve_js_1.isogenyMap)(Fp, [
- // xNum
- [
- '0x8e38e38e38e38e38e38e38e38e38e38e38e38e38e38e38e38e38e38daaaaa8c7',
- '0x7d3d4c80bc321d5b9f315cea7fd44c5d595d2fc0bf63b92dfff1044f17c6581',
- '0x534c328d23f234e6e2a413deca25caece4506144037c40314ecbd0b53d9dd262',
- '0x8e38e38e38e38e38e38e38e38e38e38e38e38e38e38e38e38e38e38daaaaa88c',
- ],
- // xDen
- [
- '0xd35771193d94918a9ca34ccbb7b640dd86cd409542f8487d9fe6b745781eb49b',
- '0xedadc6f64383dc1df7c4b2d51b54225406d36b641f5e41bbc52a56612a8c6d14',
- '0x0000000000000000000000000000000000000000000000000000000000000001', // LAST 1
- ],
- // yNum
- [
- '0x4bda12f684bda12f684bda12f684bda12f684bda12f684bda12f684b8e38e23c',
- '0xc75e0c32d5cb7c0fa9d0a54b12a0a6d5647ab046d686da6fdffc90fc201d71a3',
- '0x29a6194691f91a73715209ef6512e576722830a201be2018a765e85a9ecee931',
- '0x2f684bda12f684bda12f684bda12f684bda12f684bda12f684bda12f38e38d84',
- ],
- // yDen
- [
- '0xfffffffffffffffffffffffffffffffffffffffffffffffffffffffefffff93b',
- '0x7a06534bb8bdb49fd5e9e6632722c2989467c1bfc8e8d978dfb425d2685c2573',
- '0x6484aa716545ca2cf3a70c3fa8fe337e0a3d21162f0d6299a7bf8192bfd2a76f',
- '0x0000000000000000000000000000000000000000000000000000000000000001', // LAST 1
- ],
- ].map((i) => i.map((j) => BigInt(j)))))();
- const mapSWU = /* @__PURE__ */ (() => (0, weierstrass_js_1.mapToCurveSimpleSWU)(Fp, {
- A: BigInt('0x3f8731abdd661adca08a5558f0f5d272e953d363cb6f0e5d405447c01a444533'),
- B: BigInt('1771'),
- Z: Fp.create(BigInt('-11')),
- }))();
- const htf = /* @__PURE__ */ (() => (0, hash_to_curve_js_1.createHasher)(exports.secp256k1.ProjectivePoint, (scalars) => {
- const { x, y } = mapSWU(Fp.create(scalars[0]));
- return isoMap(x, y);
- }, {
- DST: 'secp256k1_XMD:SHA-256_SSWU_RO_',
- encodeDST: 'secp256k1_XMD:SHA-256_SSWU_NU_',
- p: Fp.ORDER,
- m: 1,
- k: 128,
- expand: 'xmd',
- hash: sha256_1.sha256,
- }))();
- exports.hashToCurve = (() => htf.hashToCurve)();
- exports.encodeToCurve = (() => htf.encodeToCurve)();
- //# sourceMappingURL=secp256k1.js.map
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