| 123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182183184185186187188189190191192193194195196197198199200201202203204205206207208209210211212213214215216217218219220221222223224225226227228229230231232233234235236237238239240241242243244245246247248249250251252253254255256257258259260261262263264265266267268269270271272273274275276277278279280281282283284285286287288289290291292293294295296297298299300301302303304305306307308309310311312313314315316317318319320321322323324325326327328329330331332333334335336337338339340341342343344345346347348349350351352353354355356357358359360361362363364365366367368369370371372373374375376377378379380381382383384385386387388389390391392393394395396397398399400401402403404405406407408409410411412413414415416417418419420421422423424425426427428429430431432433434435436437438439 | "use strict";Object.defineProperty(exports, "__esModule", { value: true });exports.isNegativeLE = void 0;exports.mod = mod;exports.pow = pow;exports.pow2 = pow2;exports.invert = invert;exports.tonelliShanks = tonelliShanks;exports.FpSqrt = FpSqrt;exports.validateField = validateField;exports.FpPow = FpPow;exports.FpInvertBatch = FpInvertBatch;exports.FpDiv = FpDiv;exports.FpIsSquare = FpIsSquare;exports.nLength = nLength;exports.Field = Field;exports.FpSqrtOdd = FpSqrtOdd;exports.FpSqrtEven = FpSqrtEven;exports.hashToPrivateScalar = hashToPrivateScalar;exports.getFieldBytesLength = getFieldBytesLength;exports.getMinHashLength = getMinHashLength;exports.mapHashToField = mapHashToField;/*! noble-curves - MIT License (c) 2022 Paul Miller (paulmillr.com) */// Utilities for modular arithmetics and finite fieldsconst utils_js_1 = require("./utils.js");// prettier-ignoreconst _0n = BigInt(0), _1n = BigInt(1), _2n = BigInt(2), _3n = BigInt(3);// prettier-ignoreconst _4n = BigInt(4), _5n = BigInt(5), _8n = BigInt(8);// prettier-ignoreconst _9n = BigInt(9), _16n = BigInt(16);// Calculates a modulo bfunction mod(a, b) {    const result = a % b;    return result >= _0n ? result : b + result;}/** * Efficiently raise num to power and do modular division. * Unsafe in some contexts: uses ladder, so can expose bigint bits. * @example * pow(2n, 6n, 11n) // 64n % 11n == 9n */// TODO: use field version && removefunction pow(num, power, modulo) {    if (modulo <= _0n || power < _0n)        throw new Error('Expected power/modulo > 0');    if (modulo === _1n)        return _0n;    let res = _1n;    while (power > _0n) {        if (power & _1n)            res = (res * num) % modulo;        num = (num * num) % modulo;        power >>= _1n;    }    return res;}// Does x ^ (2 ^ power) mod p. pow2(30, 4) == 30 ^ (2 ^ 4)function pow2(x, power, modulo) {    let res = x;    while (power-- > _0n) {        res *= res;        res %= modulo;    }    return res;}// Inverses number over modulofunction invert(number, modulo) {    if (number === _0n || modulo <= _0n) {        throw new Error(`invert: expected positive integers, got n=${number} mod=${modulo}`);    }    // Euclidean GCD https://brilliant.org/wiki/extended-euclidean-algorithm/    // Fermat's little theorem "CT-like" version inv(n) = n^(m-2) mod m is 30x slower.    let a = mod(number, modulo);    let b = modulo;    // prettier-ignore    let x = _0n, y = _1n, u = _1n, v = _0n;    while (a !== _0n) {        // JIT applies optimization if those two lines follow each other        const q = b / a;        const r = b % a;        const m = x - u * q;        const n = y - v * q;        // prettier-ignore        b = a, a = r, x = u, y = v, u = m, v = n;    }    const gcd = b;    if (gcd !== _1n)        throw new Error('invert: does not exist');    return mod(x, modulo);}/** * Tonelli-Shanks square root search algorithm. * 1. https://eprint.iacr.org/2012/685.pdf (page 12) * 2. Square Roots from 1; 24, 51, 10 to Dan Shanks * Will start an infinite loop if field order P is not prime. * @param P field order * @returns function that takes field Fp (created from P) and number n */function tonelliShanks(P) {    // Legendre constant: used to calculate Legendre symbol (a | p),    // which denotes the value of a^((p-1)/2) (mod p).    // (a | p) ≡ 1    if a is a square (mod p)    // (a | p) ≡ -1   if a is not a square (mod p)    // (a | p) ≡ 0    if a ≡ 0 (mod p)    const legendreC = (P - _1n) / _2n;    let Q, S, Z;    // Step 1: By factoring out powers of 2 from p - 1,    // find q and s such that p - 1 = q*(2^s) with q odd    for (Q = P - _1n, S = 0; Q % _2n === _0n; Q /= _2n, S++)        ;    // Step 2: Select a non-square z such that (z | p) ≡ -1 and set c ≡ zq    for (Z = _2n; Z < P && pow(Z, legendreC, P) !== P - _1n; Z++)        ;    // Fast-path    if (S === 1) {        const p1div4 = (P + _1n) / _4n;        return function tonelliFast(Fp, n) {            const root = Fp.pow(n, p1div4);            if (!Fp.eql(Fp.sqr(root), n))                throw new Error('Cannot find square root');            return root;        };    }    // Slow-path    const Q1div2 = (Q + _1n) / _2n;    return function tonelliSlow(Fp, n) {        // Step 0: Check that n is indeed a square: (n | p) should not be ≡ -1        if (Fp.pow(n, legendreC) === Fp.neg(Fp.ONE))            throw new Error('Cannot find square root');        let r = S;        // TODO: will fail at Fp2/etc        let g = Fp.pow(Fp.mul(Fp.ONE, Z), Q); // will update both x and b        let x = Fp.pow(n, Q1div2); // first guess at the square root        let b = Fp.pow(n, Q); // first guess at the fudge factor        while (!Fp.eql(b, Fp.ONE)) {            if (Fp.eql(b, Fp.ZERO))                return Fp.ZERO; // https://en.wikipedia.org/wiki/Tonelli%E2%80%93Shanks_algorithm (4. If t = 0, return r = 0)            // Find m such b^(2^m)==1            let m = 1;            for (let t2 = Fp.sqr(b); m < r; m++) {                if (Fp.eql(t2, Fp.ONE))                    break;                t2 = Fp.sqr(t2); // t2 *= t2            }            // NOTE: r-m-1 can be bigger than 32, need to convert to bigint before shift, otherwise there will be overflow            const ge = Fp.pow(g, _1n << BigInt(r - m - 1)); // ge = 2^(r-m-1)            g = Fp.sqr(ge); // g = ge * ge            x = Fp.mul(x, ge); // x *= ge            b = Fp.mul(b, g); // b *= g            r = m;        }        return x;    };}function FpSqrt(P) {    // NOTE: different algorithms can give different roots, it is up to user to decide which one they want.    // For example there is FpSqrtOdd/FpSqrtEven to choice root based on oddness (used for hash-to-curve).    // P ≡ 3 (mod 4)    // √n = n^((P+1)/4)    if (P % _4n === _3n) {        // Not all roots possible!        // const ORDER =        //   0x1a0111ea397fe69a4b1ba7b6434bacd764774b84f38512bf6730d2a0f6b0f6241eabfffeb153ffffb9feffffffffaaabn;        // const NUM = 72057594037927816n;        const p1div4 = (P + _1n) / _4n;        return function sqrt3mod4(Fp, n) {            const root = Fp.pow(n, p1div4);            // Throw if root**2 != n            if (!Fp.eql(Fp.sqr(root), n))                throw new Error('Cannot find square root');            return root;        };    }    // Atkin algorithm for q ≡ 5 (mod 8), https://eprint.iacr.org/2012/685.pdf (page 10)    if (P % _8n === _5n) {        const c1 = (P - _5n) / _8n;        return function sqrt5mod8(Fp, n) {            const n2 = Fp.mul(n, _2n);            const v = Fp.pow(n2, c1);            const nv = Fp.mul(n, v);            const i = Fp.mul(Fp.mul(nv, _2n), v);            const root = Fp.mul(nv, Fp.sub(i, Fp.ONE));            if (!Fp.eql(Fp.sqr(root), n))                throw new Error('Cannot find square root');            return root;        };    }    // P ≡ 9 (mod 16)    if (P % _16n === _9n) {        // NOTE: tonelli is too slow for bls-Fp2 calculations even on start        // Means we cannot use sqrt for constants at all!        //        // const c1 = Fp.sqrt(Fp.negate(Fp.ONE)); //  1. c1 = sqrt(-1) in F, i.e., (c1^2) == -1 in F        // const c2 = Fp.sqrt(c1);                //  2. c2 = sqrt(c1) in F, i.e., (c2^2) == c1 in F        // const c3 = Fp.sqrt(Fp.negate(c1));     //  3. c3 = sqrt(-c1) in F, i.e., (c3^2) == -c1 in F        // const c4 = (P + _7n) / _16n;           //  4. c4 = (q + 7) / 16        # Integer arithmetic        // sqrt = (x) => {        //   let tv1 = Fp.pow(x, c4);             //  1. tv1 = x^c4        //   let tv2 = Fp.mul(c1, tv1);           //  2. tv2 = c1 * tv1        //   const tv3 = Fp.mul(c2, tv1);         //  3. tv3 = c2 * tv1        //   let tv4 = Fp.mul(c3, tv1);           //  4. tv4 = c3 * tv1        //   const e1 = Fp.equals(Fp.square(tv2), x); //  5.  e1 = (tv2^2) == x        //   const e2 = Fp.equals(Fp.square(tv3), x); //  6.  e2 = (tv3^2) == x        //   tv1 = Fp.cmov(tv1, tv2, e1); //  7. tv1 = CMOV(tv1, tv2, e1)  # Select tv2 if (tv2^2) == x        //   tv2 = Fp.cmov(tv4, tv3, e2); //  8. tv2 = CMOV(tv4, tv3, e2)  # Select tv3 if (tv3^2) == x        //   const e3 = Fp.equals(Fp.square(tv2), x); //  9.  e3 = (tv2^2) == x        //   return Fp.cmov(tv1, tv2, e3); //  10.  z = CMOV(tv1, tv2, e3)  # Select the sqrt from tv1 and tv2        // }    }    // Other cases: Tonelli-Shanks algorithm    return tonelliShanks(P);}// Little-endian check for first LE bit (last BE bit);const isNegativeLE = (num, modulo) => (mod(num, modulo) & _1n) === _1n;exports.isNegativeLE = isNegativeLE;// prettier-ignoreconst FIELD_FIELDS = [    'create', 'isValid', 'is0', 'neg', 'inv', 'sqrt', 'sqr',    'eql', 'add', 'sub', 'mul', 'pow', 'div',    'addN', 'subN', 'mulN', 'sqrN'];function validateField(field) {    const initial = {        ORDER: 'bigint',        MASK: 'bigint',        BYTES: 'isSafeInteger',        BITS: 'isSafeInteger',    };    const opts = FIELD_FIELDS.reduce((map, val) => {        map[val] = 'function';        return map;    }, initial);    return (0, utils_js_1.validateObject)(field, opts);}// Generic field functions/** * Same as `pow` but for Fp: non-constant-time. * Unsafe in some contexts: uses ladder, so can expose bigint bits. */function FpPow(f, num, power) {    // Should have same speed as pow for bigints    // TODO: benchmark!    if (power < _0n)        throw new Error('Expected power > 0');    if (power === _0n)        return f.ONE;    if (power === _1n)        return num;    let p = f.ONE;    let d = num;    while (power > _0n) {        if (power & _1n)            p = f.mul(p, d);        d = f.sqr(d);        power >>= _1n;    }    return p;}/** * Efficiently invert an array of Field elements. * `inv(0)` will return `undefined` here: make sure to throw an error. */function FpInvertBatch(f, nums) {    const tmp = new Array(nums.length);    // Walk from first to last, multiply them by each other MOD p    const lastMultiplied = nums.reduce((acc, num, i) => {        if (f.is0(num))            return acc;        tmp[i] = acc;        return f.mul(acc, num);    }, f.ONE);    // Invert last element    const inverted = f.inv(lastMultiplied);    // Walk from last to first, multiply them by inverted each other MOD p    nums.reduceRight((acc, num, i) => {        if (f.is0(num))            return acc;        tmp[i] = f.mul(acc, tmp[i]);        return f.mul(acc, num);    }, inverted);    return tmp;}function FpDiv(f, lhs, rhs) {    return f.mul(lhs, typeof rhs === 'bigint' ? invert(rhs, f.ORDER) : f.inv(rhs));}// This function returns True whenever the value x is a square in the field F.function FpIsSquare(f) {    const legendreConst = (f.ORDER - _1n) / _2n; // Integer arithmetic    return (x) => {        const p = f.pow(x, legendreConst);        return f.eql(p, f.ZERO) || f.eql(p, f.ONE);    };}// CURVE.n lengthsfunction nLength(n, nBitLength) {    // Bit size, byte size of CURVE.n    const _nBitLength = nBitLength !== undefined ? nBitLength : n.toString(2).length;    const nByteLength = Math.ceil(_nBitLength / 8);    return { nBitLength: _nBitLength, nByteLength };}/** * Initializes a finite field over prime. **Non-primes are not supported.** * Do not init in loop: slow. Very fragile: always run a benchmark on a change. * Major performance optimizations: * * a) denormalized operations like mulN instead of mul * * b) same object shape: never add or remove keys * * c) Object.freeze * @param ORDER prime positive bigint * @param bitLen how many bits the field consumes * @param isLE (def: false) if encoding / decoding should be in little-endian * @param redef optional faster redefinitions of sqrt and other methods */function Field(ORDER, bitLen, isLE = false, redef = {}) {    if (ORDER <= _0n)        throw new Error(`Expected Field ORDER > 0, got ${ORDER}`);    const { nBitLength: BITS, nByteLength: BYTES } = nLength(ORDER, bitLen);    if (BYTES > 2048)        throw new Error('Field lengths over 2048 bytes are not supported');    const sqrtP = FpSqrt(ORDER);    const f = Object.freeze({        ORDER,        BITS,        BYTES,        MASK: (0, utils_js_1.bitMask)(BITS),        ZERO: _0n,        ONE: _1n,        create: (num) => mod(num, ORDER),        isValid: (num) => {            if (typeof num !== 'bigint')                throw new Error(`Invalid field element: expected bigint, got ${typeof num}`);            return _0n <= num && num < ORDER; // 0 is valid element, but it's not invertible        },        is0: (num) => num === _0n,        isOdd: (num) => (num & _1n) === _1n,        neg: (num) => mod(-num, ORDER),        eql: (lhs, rhs) => lhs === rhs,        sqr: (num) => mod(num * num, ORDER),        add: (lhs, rhs) => mod(lhs + rhs, ORDER),        sub: (lhs, rhs) => mod(lhs - rhs, ORDER),        mul: (lhs, rhs) => mod(lhs * rhs, ORDER),        pow: (num, power) => FpPow(f, num, power),        div: (lhs, rhs) => mod(lhs * invert(rhs, ORDER), ORDER),        // Same as above, but doesn't normalize        sqrN: (num) => num * num,        addN: (lhs, rhs) => lhs + rhs,        subN: (lhs, rhs) => lhs - rhs,        mulN: (lhs, rhs) => lhs * rhs,        inv: (num) => invert(num, ORDER),        sqrt: redef.sqrt || ((n) => sqrtP(f, n)),        invertBatch: (lst) => FpInvertBatch(f, lst),        // TODO: do we really need constant cmov?        // We don't have const-time bigints anyway, so probably will be not very useful        cmov: (a, b, c) => (c ? b : a),        toBytes: (num) => (isLE ? (0, utils_js_1.numberToBytesLE)(num, BYTES) : (0, utils_js_1.numberToBytesBE)(num, BYTES)),        fromBytes: (bytes) => {            if (bytes.length !== BYTES)                throw new Error(`Fp.fromBytes: expected ${BYTES}, got ${bytes.length}`);            return isLE ? (0, utils_js_1.bytesToNumberLE)(bytes) : (0, utils_js_1.bytesToNumberBE)(bytes);        },    });    return Object.freeze(f);}function FpSqrtOdd(Fp, elm) {    if (!Fp.isOdd)        throw new Error(`Field doesn't have isOdd`);    const root = Fp.sqrt(elm);    return Fp.isOdd(root) ? root : Fp.neg(root);}function FpSqrtEven(Fp, elm) {    if (!Fp.isOdd)        throw new Error(`Field doesn't have isOdd`);    const root = Fp.sqrt(elm);    return Fp.isOdd(root) ? Fp.neg(root) : root;}/** * "Constant-time" private key generation utility. * Same as mapKeyToField, but accepts less bytes (40 instead of 48 for 32-byte field). * Which makes it slightly more biased, less secure. * @deprecated use mapKeyToField instead */function hashToPrivateScalar(hash, groupOrder, isLE = false) {    hash = (0, utils_js_1.ensureBytes)('privateHash', hash);    const hashLen = hash.length;    const minLen = nLength(groupOrder).nByteLength + 8;    if (minLen < 24 || hashLen < minLen || hashLen > 1024)        throw new Error(`hashToPrivateScalar: expected ${minLen}-1024 bytes of input, got ${hashLen}`);    const num = isLE ? (0, utils_js_1.bytesToNumberLE)(hash) : (0, utils_js_1.bytesToNumberBE)(hash);    return mod(num, groupOrder - _1n) + _1n;}/** * Returns total number of bytes consumed by the field element. * For example, 32 bytes for usual 256-bit weierstrass curve. * @param fieldOrder number of field elements, usually CURVE.n * @returns byte length of field */function getFieldBytesLength(fieldOrder) {    if (typeof fieldOrder !== 'bigint')        throw new Error('field order must be bigint');    const bitLength = fieldOrder.toString(2).length;    return Math.ceil(bitLength / 8);}/** * Returns minimal amount of bytes that can be safely reduced * by field order. * Should be 2^-128 for 128-bit curve such as P256. * @param fieldOrder number of field elements, usually CURVE.n * @returns byte length of target hash */function getMinHashLength(fieldOrder) {    const length = getFieldBytesLength(fieldOrder);    return length + Math.ceil(length / 2);}/** * "Constant-time" private key generation utility. * Can take (n + n/2) or more bytes of uniform input e.g. from CSPRNG or KDF * and convert them into private scalar, with the modulo bias being negligible. * Needs at least 48 bytes of input for 32-byte private key. * https://research.kudelskisecurity.com/2020/07/28/the-definitive-guide-to-modulo-bias-and-how-to-avoid-it/ * FIPS 186-5, A.2 https://csrc.nist.gov/publications/detail/fips/186/5/final * RFC 9380, https://www.rfc-editor.org/rfc/rfc9380#section-5 * @param hash hash output from SHA3 or a similar function * @param groupOrder size of subgroup - (e.g. secp256k1.CURVE.n) * @param isLE interpret hash bytes as LE num * @returns valid private scalar */function mapHashToField(key, fieldOrder, isLE = false) {    const len = key.length;    const fieldLen = getFieldBytesLength(fieldOrder);    const minLen = getMinHashLength(fieldOrder);    // No small numbers: need to understand bias story. No huge numbers: easier to detect JS timings.    if (len < 16 || len < minLen || len > 1024)        throw new Error(`expected ${minLen}-1024 bytes of input, got ${len}`);    const num = isLE ? (0, utils_js_1.bytesToNumberBE)(key) : (0, utils_js_1.bytesToNumberLE)(key);    // `mod(x, 11)` can sometimes produce 0. `mod(x, 10) + 1` is the same, but no 0    const reduced = mod(num, fieldOrder - _1n) + _1n;    return isLE ? (0, utils_js_1.numberToBytesLE)(reduced, fieldLen) : (0, utils_js_1.numberToBytesBE)(reduced, fieldLen);}//# sourceMappingURL=modular.js.map
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