forked from tornado-packages/noble-curves
mod, utils, weierstrass, secp: improve hex errors. secp: improve verify() logic and schnorr
This commit is contained in:
Paul Miller
parent
4d311d7294
commit
e1910e85ea
@ -407,7 +407,7 @@ export function hashToPrivateScalar(
|
||||
groupOrder: bigint,
|
||||
isLE = false
|
||||
): bigint {
|
||||
hash = ensureBytes(hash);
|
||||
hash = ensureBytes('privateHash', hash);
|
||||
const hashLen = hash.length;
|
||||
const minLen = nLength(groupOrder).nByteLength + 8;
|
||||
if (minLen < 24 || hashLen < minLen || hashLen > 1024)
|
||||
|
||||
@ -33,14 +33,14 @@ export function numberToHexUnpadded(num: number | bigint): string {
|
||||
}
|
||||
|
||||
export function hexToNumber(hex: string): bigint {
|
||||
if (typeof hex !== 'string') throw new Error('string expected, got ' + typeof hex);
|
||||
if (typeof hex !== 'string') throw new Error('hex string expected, got ' + typeof hex);
|
||||
// Big Endian
|
||||
return BigInt(hex === '' ? '0' : `0x${hex}`);
|
||||
}
|
||||
|
||||
// Caching slows it down 2-3x
|
||||
export function hexToBytes(hex: string): Uint8Array {
|
||||
if (typeof hex !== 'string') throw new Error('string expected, got ' + typeof hex);
|
||||
if (typeof hex !== 'string') throw new Error('hex string expected, got ' + typeof hex);
|
||||
if (hex.length % 2) throw new Error('hex string is invalid: unpadded ' + hex.length);
|
||||
const array = new Uint8Array(hex.length / 2);
|
||||
for (let i = 0; i < array.length; i++) {
|
||||
@ -68,13 +68,25 @@ export const numberToBytesLE = (n: bigint, len: number) => numberToBytesBE(n, le
|
||||
// Returns variable number bytes (minimal bigint encoding?)
|
||||
export const numberToVarBytesBE = (n: bigint) => hexToBytes(numberToHexUnpadded(n));
|
||||
|
||||
export function ensureBytes(hex: Hex, expectedLength?: number): Uint8Array {
|
||||
// Uint8Array.from() instead of hash.slice() because node.js Buffer
|
||||
// is instance of Uint8Array, and its slice() creates **mutable** copy
|
||||
const bytes = u8a(hex) ? Uint8Array.from(hex) : hexToBytes(hex);
|
||||
if (typeof expectedLength === 'number' && bytes.length !== expectedLength)
|
||||
throw new Error(`Expected ${expectedLength} bytes`);
|
||||
return bytes;
|
||||
export function ensureBytes(title: string, hex: Hex, expectedLength?: number): Uint8Array {
|
||||
let res: Uint8Array;
|
||||
if (typeof hex === 'string') {
|
||||
try {
|
||||
res = hexToBytes(hex);
|
||||
} catch (e) {
|
||||
throw new Error(`${title} must be valid hex string, got "${hex}". Cause: ${e}`);
|
||||
}
|
||||
} else if (u8a(hex)) {
|
||||
// Uint8Array.from() instead of hash.slice() because node.js Buffer
|
||||
// is instance of Uint8Array, and its slice() creates **mutable** copy
|
||||
res = Uint8Array.from(hex);
|
||||
} else {
|
||||
throw new Error(`${title} must be hex string or Uint8Array`);
|
||||
}
|
||||
const len = res.length;
|
||||
if (typeof expectedLength === 'number' && len !== expectedLength)
|
||||
throw new Error(`${title} expected ${expectedLength} bytes, got ${len}`);
|
||||
return res;
|
||||
}
|
||||
|
||||
// Copies several Uint8Arrays into one.
|
||||
@ -96,6 +108,16 @@ export function equalBytes(b1: Uint8Array, b2: Uint8Array) {
|
||||
return true;
|
||||
}
|
||||
|
||||
// Global symbols in both browsers and Node.js since v11
|
||||
// See https://github.com/microsoft/TypeScript/issues/31535
|
||||
declare const TextEncoder: any;
|
||||
export function utf8ToBytes(str: string): Uint8Array {
|
||||
if (typeof str !== 'string') {
|
||||
throw new Error(`utf8ToBytes expected string, got ${typeof str}`);
|
||||
}
|
||||
return new TextEncoder().encode(str);
|
||||
}
|
||||
|
||||
// Bit operations
|
||||
|
||||
// Amount of bits inside bigint (Same as n.toString(2).length)
|
||||
|
||||
@ -59,9 +59,6 @@ export interface ProjPointType<T> extends Group<ProjPointType<T>> {
|
||||
readonly py: T;
|
||||
readonly pz: T;
|
||||
multiply(scalar: bigint): ProjPointType<T>;
|
||||
multiplyUnsafe(scalar: bigint): ProjPointType<T>;
|
||||
multiplyAndAddUnsafe(Q: ProjPointType<T>, a: bigint, b: bigint): ProjPointType<T> | undefined;
|
||||
_setWindowSize(windowSize: number): void;
|
||||
toAffine(iz?: T): AffinePoint<T>;
|
||||
isTorsionFree(): boolean;
|
||||
clearCofactor(): ProjPointType<T>;
|
||||
@ -69,6 +66,10 @@ export interface ProjPointType<T> extends Group<ProjPointType<T>> {
|
||||
hasEvenY(): boolean;
|
||||
toRawBytes(isCompressed?: boolean): Uint8Array;
|
||||
toHex(isCompressed?: boolean): string;
|
||||
|
||||
multiplyUnsafe(scalar: bigint): ProjPointType<T>;
|
||||
multiplyAndAddUnsafe(Q: ProjPointType<T>, a: bigint, b: bigint): ProjPointType<T> | undefined;
|
||||
_setWindowSize(windowSize: number): void;
|
||||
}
|
||||
// Static methods for 3d XYZ points
|
||||
export interface ProjConstructor<T> extends GroupConstructor<ProjPointType<T>> {
|
||||
@ -213,7 +214,10 @@ export function weierstrassPoints<T>(opts: CurvePointsType<T>) {
|
||||
}
|
||||
let num: bigint;
|
||||
try {
|
||||
num = typeof key === 'bigint' ? key : ut.bytesToNumberBE(ensureBytes(key, nByteLength));
|
||||
num =
|
||||
typeof key === 'bigint'
|
||||
? key
|
||||
: ut.bytesToNumberBE(ensureBytes('private key', key, nByteLength));
|
||||
} catch (error) {
|
||||
throw new Error(`private key must be ${nByteLength} bytes, hex or bigint, not ${typeof key}`);
|
||||
}
|
||||
@ -276,7 +280,7 @@ export function weierstrassPoints<T>(opts: CurvePointsType<T>) {
|
||||
* @param hex short/long ECDSA hex
|
||||
*/
|
||||
static fromHex(hex: Hex): Point {
|
||||
const P = Point.fromAffine(CURVE.fromBytes(ensureBytes(hex)));
|
||||
const P = Point.fromAffine(CURVE.fromBytes(ensureBytes('pointHex', hex)));
|
||||
P.assertValidity();
|
||||
return P;
|
||||
}
|
||||
@ -782,24 +786,22 @@ export function weierstrass(curveDef: CurveType): CurveFn {
|
||||
|
||||
// pair (bytes of r, bytes of s)
|
||||
static fromCompact(hex: Hex) {
|
||||
const gl = CURVE.nByteLength;
|
||||
hex = ensureBytes(hex, gl * 2);
|
||||
return new Signature(slcNum(hex, 0, gl), slcNum(hex, gl, 2 * gl));
|
||||
const l = CURVE.nByteLength;
|
||||
hex = ensureBytes('compactSignature', hex, l * 2);
|
||||
return new Signature(slcNum(hex, 0, l), slcNum(hex, l, 2 * l));
|
||||
}
|
||||
|
||||
// DER encoded ECDSA signature
|
||||
// https://bitcoin.stackexchange.com/questions/57644/what-are-the-parts-of-a-bitcoin-transaction-input-script
|
||||
static fromDER(hex: Hex) {
|
||||
if (typeof hex !== 'string' && !(hex instanceof Uint8Array))
|
||||
throw new Error(`Signature.fromDER: Expected string or Uint8Array`);
|
||||
const { r, s } = DER.toSig(ensureBytes(hex));
|
||||
const { r, s } = DER.toSig(ensureBytes('DER', hex));
|
||||
return new Signature(r, s);
|
||||
}
|
||||
|
||||
assertValidity(): void {
|
||||
// can use assertGE here
|
||||
if (!isWithinCurveOrder(this.r)) throw new Error('r must be 0 < r < n');
|
||||
if (!isWithinCurveOrder(this.s)) throw new Error('s must be 0 < s < n');
|
||||
if (!isWithinCurveOrder(this.r)) throw new Error('r must be 0 < r < CURVE.n');
|
||||
if (!isWithinCurveOrder(this.s)) throw new Error('s must be 0 < s < CURVE.n');
|
||||
}
|
||||
|
||||
addRecoveryBit(recovery: number) {
|
||||
@ -807,11 +809,10 @@ export function weierstrass(curveDef: CurveType): CurveFn {
|
||||
}
|
||||
|
||||
recoverPublicKey(msgHash: Hex): typeof Point.BASE {
|
||||
const { n: N } = CURVE; // ECDSA public key recovery secg.org/sec1-v2.pdf 4.1.6
|
||||
const { r, s, recovery: rec } = this;
|
||||
const h = bits2int_modN(ensureBytes(msgHash)); // Truncate hash
|
||||
const h = bits2int_modN(ensureBytes('msgHash', msgHash)); // Truncate hash
|
||||
if (rec == null || ![0, 1, 2, 3].includes(rec)) throw new Error('recovery id invalid');
|
||||
const radj = rec === 2 || rec === 3 ? r + N : r;
|
||||
const radj = rec === 2 || rec === 3 ? r + CURVE.n : r;
|
||||
if (radj >= Fp.ORDER) throw new Error('recovery id 2 or 3 invalid');
|
||||
const prefix = (rec & 1) === 0 ? '02' : '03';
|
||||
const R = Point.fromHex(prefix + numToNByteStr(radj));
|
||||
@ -936,8 +937,8 @@ export function weierstrass(curveDef: CurveType): CurveFn {
|
||||
function (bytes: Uint8Array): bigint {
|
||||
// For curves with nBitLength % 8 !== 0: bits2octets(bits2octets(m)) !== bits2octets(m)
|
||||
// for some cases, since bytes.length * 8 is not actual bitLength.
|
||||
const delta = bytes.length * 8 - CURVE.nBitLength; // truncate to nBitLength leftmost bits
|
||||
const num = ut.bytesToNumberBE(bytes); // check for == u8 done here
|
||||
const delta = bytes.length * 8 - CURVE.nBitLength; // truncate to nBitLength leftmost bits
|
||||
return delta > 0 ? num >> BigInt(delta) : num;
|
||||
};
|
||||
const bits2int_modN =
|
||||
@ -962,26 +963,25 @@ export function weierstrass(curveDef: CurveType): CurveFn {
|
||||
// NOTE: we cannot assume here that msgHash has same amount of bytes as curve order, this will be wrong at least for P521.
|
||||
// Also it can be bigger for P224 + SHA256
|
||||
function prepSig(msgHash: Hex, privateKey: PrivKey, opts = defaultSigOpts) {
|
||||
const { hash, randomBytes } = CURVE;
|
||||
if (msgHash == null) throw new Error(`sign: expected valid message hash, not "${msgHash}"`);
|
||||
if (['recovered', 'canonical'].some((k) => k in opts))
|
||||
// Ban legacy options
|
||||
throw new Error('sign() legacy options not supported');
|
||||
const { hash, randomBytes } = CURVE;
|
||||
let { lowS, prehash, extraEntropy: ent } = opts; // generates low-s sigs by default
|
||||
if (prehash) msgHash = hash(ensureBytes(msgHash));
|
||||
if (lowS == null) lowS = true; // RFC6979 3.2: we skip step A, because we already provide hash
|
||||
msgHash = ensureBytes('msgHash', msgHash);
|
||||
if (prehash) msgHash = ensureBytes('prehashed msgHash', hash(msgHash));
|
||||
|
||||
// We can't later call bits2octets, since nested bits2int is broken for curves
|
||||
// with nBitLength % 8 !== 0. Because of that, we unwrap it here as int2octets call.
|
||||
// const bits2octets = (bits) => int2octets(bits2int_modN(bits))
|
||||
const h1int = bits2int_modN(ensureBytes(msgHash));
|
||||
const h1int = bits2int_modN(msgHash);
|
||||
const d = normalizePrivateKey(privateKey); // validate private key, convert to bigint
|
||||
const seedArgs = [int2octets(d), int2octets(h1int)];
|
||||
// extraEntropy. RFC6979 3.6: additional k' (optional).
|
||||
if (ent != null) {
|
||||
// K = HMAC_K(V || 0x00 || int2octets(x) || bits2octets(h1) || k')
|
||||
// Either pass as-is, or generate random bytes. Then validate for being ui8a of size BYTES
|
||||
seedArgs.push(ensureBytes(ent === true ? randomBytes(Fp.BYTES) : ent, Fp.BYTES));
|
||||
const e = ent === true ? randomBytes(Fp.BYTES) : ent; // generate random bytes OR pass as-is
|
||||
seedArgs.push(ensureBytes('extraEntropy', e, Fp.BYTES)); // check for being of size BYTES
|
||||
}
|
||||
const seed = ut.concatBytes(...seedArgs); // Step D of RFC6979 3.2
|
||||
const m = h1int; // NOTE: no need to call bits2int second time here, it is inside truncateHash!
|
||||
@ -1057,30 +1057,38 @@ export function weierstrass(curveDef: CurveType): CurveFn {
|
||||
publicKey: Hex,
|
||||
opts = defaultVerOpts
|
||||
): boolean {
|
||||
let P: ProjPointType<bigint>;
|
||||
const sg = signature;
|
||||
msgHash = ensureBytes('msgHash', msgHash);
|
||||
publicKey = ensureBytes('publicKey', publicKey);
|
||||
if ('strict' in opts) throw new Error('options.strict was renamed to lowS');
|
||||
const { lowS, prehash } = opts;
|
||||
|
||||
let _sig: Signature | undefined = undefined;
|
||||
if (publicKey instanceof Point) throw new Error('publicKey must be hex');
|
||||
let P: ProjPointType<bigint>;
|
||||
try {
|
||||
if (signature && typeof signature === 'object' && !(signature instanceof Uint8Array)) {
|
||||
const { r, s } = signature;
|
||||
_sig = new Signature(r, s); // assertValidity() is executed on creation
|
||||
} else {
|
||||
if (typeof sg === 'string' || sg instanceof Uint8Array) {
|
||||
// Signature can be represented in 2 ways: compact (2*nByteLength) & DER (variable-length).
|
||||
// Since DER can also be 2*nByteLength bytes, we check for it first.
|
||||
try {
|
||||
_sig = Signature.fromDER(signature as Hex);
|
||||
_sig = Signature.fromDER(sg);
|
||||
} catch (derError) {
|
||||
if (!(derError instanceof DER.Err)) throw derError;
|
||||
_sig = Signature.fromCompact(signature as Hex);
|
||||
_sig = Signature.fromCompact(sg);
|
||||
}
|
||||
} else if (typeof sg === 'object' && typeof sg.r === 'bigint' && typeof sg.s === 'bigint') {
|
||||
const { r, s } = sg;
|
||||
_sig = new Signature(r, s);
|
||||
} else {
|
||||
throw new Error('PARSE');
|
||||
}
|
||||
msgHash = ensureBytes(msgHash);
|
||||
P = Point.fromHex(publicKey);
|
||||
} catch (error) {
|
||||
if ((error as Error).message === 'PARSE')
|
||||
throw new Error(`signature must be Signature instance, Uint8Array or hex string`);
|
||||
return false;
|
||||
}
|
||||
if (opts.lowS && _sig.hasHighS()) return false;
|
||||
if (opts.prehash) msgHash = CURVE.hash(msgHash);
|
||||
if (lowS && _sig.hasHighS()) return false;
|
||||
if (prehash) msgHash = CURVE.hash(msgHash);
|
||||
const { r, s } = _sig;
|
||||
const h = bits2int_modN(msgHash); // Cannot use fields methods, since it is group element
|
||||
const is = invN(s); // s^-1
|
||||
|
||||
114
src/secp256k1.ts
114
src/secp256k1.ts
@ -1,26 +1,12 @@
|
||||
/*! noble-curves - MIT License (c) 2022 Paul Miller (paulmillr.com) */
|
||||
import { sha256 } from '@noble/hashes/sha256';
|
||||
import { Fp as Field, mod, pow2 } from './abstract/modular.js';
|
||||
import { createCurve } from './_shortw_utils.js';
|
||||
import { ProjPointType as PointType, mapToCurveSimpleSWU } from './abstract/weierstrass.js';
|
||||
import {
|
||||
ensureBytes,
|
||||
concatBytes,
|
||||
Hex,
|
||||
bytesToNumberBE as bytesToInt,
|
||||
PrivKey,
|
||||
numberToBytesBE,
|
||||
} from './abstract/utils.js';
|
||||
import { randomBytes } from '@noble/hashes/utils';
|
||||
import { Fp as Field, mod, pow2 } from './abstract/modular.js';
|
||||
import { ProjPointType as PointType, mapToCurveSimpleSWU } from './abstract/weierstrass.js';
|
||||
import type { Hex, PrivKey } from './abstract/utils.js';
|
||||
import { bytesToNumberBE, concatBytes, ensureBytes, numberToBytesBE } from './abstract/utils.js';
|
||||
import * as htf from './abstract/hash-to-curve.js';
|
||||
|
||||
/**
|
||||
* 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%.
|
||||
* Should always be used for Projective's double-and-add multiplication.
|
||||
* For affines cached multiplication, it trades off 1/2 init time & 1/3 ram for 20% perf hit.
|
||||
* https://gist.github.com/paulmillr/eb670806793e84df628a7c434a873066
|
||||
*/
|
||||
import { createCurve } from './_shortw_utils.js';
|
||||
|
||||
const secp256k1P = BigInt('0xfffffffffffffffffffffffffffffffffffffffffffffffffffffffefffffc2f');
|
||||
const secp256k1N = BigInt('0xfffffffffffffffffffffffffffffffebaaedce6af48a03bbfd25e8cd0364141');
|
||||
@ -61,23 +47,22 @@ type Fp = bigint;
|
||||
|
||||
export const secp256k1 = createCurve(
|
||||
{
|
||||
// Params: a, b
|
||||
// Seem to be rigid https://bitcointalk.org/index.php?topic=289795.msg3183975#msg3183975
|
||||
a: BigInt(0),
|
||||
b: BigInt(7),
|
||||
// Field over which we'll do calculations;
|
||||
// 2n**256n - 2n**32n - 2n**9n - 2n**8n - 2n**7n - 2n**6n - 2n**4n - 1n
|
||||
Fp,
|
||||
// Curve order, total count of valid points in the field
|
||||
n: secp256k1N,
|
||||
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),
|
||||
// Alllow only low-S signatures by default in sign() and verify()
|
||||
lowS: true,
|
||||
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: {
|
||||
// Params taken from https://gist.github.com/paulmillr/eb670806793e84df628a7c434a873066
|
||||
beta: BigInt('0x7ae96a2b657c07106e64479eac3434e99cf0497512f58995c1396c28719501ee'),
|
||||
splitScalar: (k: bigint) => {
|
||||
const n = secp256k1N;
|
||||
@ -105,19 +90,11 @@ export const secp256k1 = createCurve(
|
||||
sha256
|
||||
);
|
||||
|
||||
// Schnorr signatures are superior to ECDSA from above.
|
||||
// Below is Schnorr-specific code as per BIP0340.
|
||||
// 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: bigint) => typeof x === 'bigint' && _0n < x && x < secp256k1P;
|
||||
const ge = (x: bigint) => typeof x === 'bigint' && _0n < x && x < secp256k1N;
|
||||
|
||||
const TAGS = {
|
||||
challenge: 'BIP0340/challenge',
|
||||
aux: 'BIP0340/aux',
|
||||
nonce: 'BIP0340/nonce',
|
||||
} as const;
|
||||
|
||||
/** An object mapping tags to their tagged hash prefix of [SHA256(tag) | SHA256(tag)] */
|
||||
const TAGGED_HASH_PREFIXES: { [tag: string]: Uint8Array } = {};
|
||||
function taggedHash(tag: string, ...messages: Uint8Array[]): Uint8Array {
|
||||
@ -132,49 +109,53 @@ function taggedHash(tag: string, ...messages: Uint8Array[]): Uint8Array {
|
||||
|
||||
const pointToBytes = (point: PointType<bigint>) => point.toRawBytes(true).slice(1);
|
||||
const numTo32b = (n: bigint) => numberToBytesBE(n, 32);
|
||||
const modP = (x: bigint) => mod(x, secp256k1P);
|
||||
const modN = (x: bigint) => mod(x, secp256k1N);
|
||||
const Point = secp256k1.ProjectivePoint;
|
||||
const GmulAdd = (Q: PointType<bigint>, a: bigint, b: bigint) =>
|
||||
Point.BASE.multiplyAndAddUnsafe(Q, a, b);
|
||||
const hex32ToInt = (key: Hex) => bytesToInt(ensureBytes(key, 32));
|
||||
function schnorrGetExtPubKey(priv: PrivKey) {
|
||||
let d = typeof priv === 'bigint' ? priv : hex32ToInt(priv);
|
||||
const d = secp256k1.utils.normPrivateKeyToScalar(priv);
|
||||
const point = Point.fromPrivateKey(d); // P = d'⋅G; 0 < d' < n check is done inside
|
||||
const scalar = point.hasEvenY() ? d : modN(-d); // d = d' if has_even_y(P), otherwise d = n-d'
|
||||
return { point, scalar, bytes: pointToBytes(point) };
|
||||
}
|
||||
function lift_x(x: bigint): PointType<bigint> {
|
||||
if (!fe(x)) throw new Error('bad x: need 0 < x < p'); // Fail if x ≥ p.
|
||||
const c = mod(x * x * x + BigInt(7), secp256k1P); // Let c = x³ + 7 mod 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 = mod(-y, secp256k1P); // Return the unique point P such that x(P) = x and
|
||||
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;
|
||||
}
|
||||
function challenge(...args: Uint8Array[]): bigint {
|
||||
return modN(bytesToInt(taggedHash(TAGS.challenge, ...args)));
|
||||
return modN(bytesToNumberBE(taggedHash('BIP0340/challenge', ...args)));
|
||||
}
|
||||
|
||||
// Schnorr's pubkey is just `x` of Point (BIP340)
|
||||
/**
|
||||
* Schnorr public key is just `x` coordinate of Point as per BIP340.
|
||||
*/
|
||||
function schnorrGetPublicKey(privateKey: Hex): Uint8Array {
|
||||
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
|
||||
/**
|
||||
* 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: Hex,
|
||||
privateKey: PrivKey,
|
||||
auxRand: Hex = randomBytes(32)
|
||||
): Uint8Array {
|
||||
if (message == null) throw new Error(`sign: Expected valid message, not "${message}"`);
|
||||
const m = ensureBytes(message); // checks for isWithinCurveOrder
|
||||
const { bytes: px, scalar: d } = schnorrGetExtPubKey(privateKey);
|
||||
const a = ensureBytes(auxRand, 32); // Auxiliary random data a: a 32-byte array
|
||||
const t = numTo32b(d ^ bytesToInt(taggedHash(TAGS.aux, a))); // Let t be the byte-wise xor of bytes(d) and hash/aux(a)
|
||||
const rand = taggedHash(TAGS.nonce, t, px, m); // Let rand = hash/nonce(t || bytes(P) || m)
|
||||
const k_ = modN(bytesToInt(rand)); // Let k' = int(rand) mod n
|
||||
const m = ensureBytes('message', message);
|
||||
const { bytes: px, scalar: d } = schnorrGetExtPubKey(privateKey); // checks for isWithinCurveOrder
|
||||
const a = ensureBytes('auxRand', auxRand, 32); // Auxiliary random data a: a 32-byte array
|
||||
const t = numTo32b(d ^ 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(bytesToNumberBE(rand)); // Let k' = int(rand) mod n
|
||||
if (k_ === _0n) throw new Error('sign failed: k is zero'); // Fail if k' = 0.
|
||||
const { point: R, 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.
|
||||
@ -187,18 +168,19 @@ function schnorrSign(
|
||||
}
|
||||
|
||||
/**
|
||||
* Verifies Schnorr signature synchronously.
|
||||
* Verifies Schnorr signature.
|
||||
*/
|
||||
function schnorrVerify(signature: Hex, message: Hex, publicKey: Hex): boolean {
|
||||
const sig = ensureBytes('signature', signature, 64);
|
||||
const m = ensureBytes('message', message);
|
||||
const pub = ensureBytes('publicKey', publicKey, 32);
|
||||
try {
|
||||
const P = lift_x(hex32ToInt(publicKey)); // P = lift_x(int(pk)); fail if that fails
|
||||
const sig = ensureBytes(signature, 64);
|
||||
const r = bytesToInt(sig.subarray(0, 32)); // Let r = int(sig[0:32]); fail if r ≥ p.
|
||||
const P = lift_x(bytesToNumberBE(pub)); // P = lift_x(int(pk)); fail if that fails
|
||||
const r = bytesToNumberBE(sig.subarray(0, 32)); // Let r = int(sig[0:32]); fail if r ≥ p.
|
||||
if (!fe(r)) return false;
|
||||
const s = bytesToInt(sig.subarray(32, 64)); // Let s = int(sig[32:64]); fail if s ≥ n.
|
||||
const s = bytesToNumberBE(sig.subarray(32, 64)); // Let s = int(sig[32:64]); fail if s ≥ n.
|
||||
if (!ge(s)) return false;
|
||||
const m = ensureBytes(message);
|
||||
const e = challenge(numTo32b(r), pointToBytes(P), m); // int(challenge(bytes(r)||bytes(P)||m)) mod n
|
||||
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.
|
||||
@ -212,11 +194,12 @@ export const schnorr = {
|
||||
sign: schnorrSign,
|
||||
verify: schnorrVerify,
|
||||
utils: {
|
||||
randomPrivateKey: secp256k1.utils.randomPrivateKey,
|
||||
getExtendedPublicKey: schnorrGetExtPubKey,
|
||||
lift_x,
|
||||
pointToBytes,
|
||||
numberToBytesBE,
|
||||
bytesToNumberBE: bytesToInt,
|
||||
bytesToNumberBE,
|
||||
taggedHash,
|
||||
mod,
|
||||
},
|
||||
@ -259,7 +242,7 @@ const mapSWU = mapToCurveSimpleSWU(Fp, {
|
||||
B: BigInt('1771'),
|
||||
Z: Fp.create(BigInt('-11')),
|
||||
});
|
||||
const { hashToCurve, encodeToCurve } = htf.hashToCurve(
|
||||
export const { hashToCurve, encodeToCurve } = htf.hashToCurve(
|
||||
secp256k1.ProjectivePoint,
|
||||
(scalars: bigint[]) => {
|
||||
const { x, y } = mapSWU(Fp.create(scalars[0]));
|
||||
@ -275,4 +258,3 @@ const { hashToCurve, encodeToCurve } = htf.hashToCurve(
|
||||
hash: sha256,
|
||||
}
|
||||
);
|
||||
export { hashToCurve, encodeToCurve };
|
||||
|
||||
Loading…
Reference in New Issue
Block a user