OverviewFilesCommitsIssuesDocsReleasesPeers

hyper-booking / node_modules / @noble / ed25519 / index.js

591 lines · javascript ref:
/*! noble-ed25519 - MIT License (c) 2019 Paul Miller (paulmillr.com) */
/**
 * 4KB JS implementation of ed25519 EdDSA signatures.
 * Compliant with RFC8032, FIPS 186-5 & ZIP215.
 * @module
 * @example
 * ```js
import * as ed from '@noble/ed25519';
(async () => {
  const privKey = ed.utils.randomPrivateKey();
  const message = Uint8Array.from([0xab, 0xbc, 0xcd, 0xde]);
  const pubKey = await ed.getPublicKeyAsync(privKey); // Sync methods are also present
  const signature = await ed.signAsync(message, privKey);
  const isValid = await ed.verifyAsync(signature, message, pubKey);
})();
```
 */
/**
 * Curve params. ed25519 is twisted edwards curve. Equation is −x² + y² = -a + dx²y².
 * * P = `2n**255n - 19n` // field over which calculations are done
 * * N = `2n**252n + 27742317777372353535851937790883648493n` // group order, amount of curve points
 * * h = 8 // cofactor
 * * a = `Fp.create(BigInt(-1))` // equation param
 * * d = -121665/121666 a.k.a. `Fp.neg(121665 * Fp.inv(121666))` // equation param
 * * Gx, Gy are coordinates of Generator / base point
 */
const ed25519_CURVE = {
    p: 0x7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffedn,
    n: 0x1000000000000000000000000000000014def9dea2f79cd65812631a5cf5d3edn,
    h: 8n,
    a: 0x7fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffecn,
    d: 0x52036cee2b6ffe738cc740797779e89800700a4d4141d8ab75eb4dca135978a3n,
    Gx: 0x216936d3cd6e53fec0a4e231fdd6dc5c692cc7609525a7b2c9562d608f25d51an,
    Gy: 0x6666666666666666666666666666666666666666666666666666666666666658n,
};
const { p: P, n: N, Gx, Gy, a: _a, d: _d } = ed25519_CURVE;
const h = 8n; // cofactor
const L = 32; // field / group byte length
const L2 = 64;
// Helpers and Precomputes sections are reused between libraries
// ## Helpers
// ----------
// error helper, messes-up stack trace
const err = (m = '') => {
    throw new Error(m);
};
const isBig = (n) => typeof n === 'bigint'; // is big integer
const isStr = (s) => typeof s === 'string'; // is string
const isBytes = (a) => a instanceof Uint8Array || (ArrayBuffer.isView(a) && a.constructor.name === 'Uint8Array');
/** assert is Uint8Array (of specific length) */
const abytes = (a, l) => !isBytes(a) || (typeof l === 'number' && l > 0 && a.length !== l)
    ? err('Uint8Array expected')
    : a;
/** create Uint8Array */
const u8n = (len) => new Uint8Array(len);
const u8fr = (buf) => Uint8Array.from(buf);
const padh = (n, pad) => n.toString(16).padStart(pad, '0');
const bytesToHex = (b) => Array.from(abytes(b))
    .map((e) => padh(e, 2))
    .join('');
const C = { _0: 48, _9: 57, A: 65, F: 70, a: 97, f: 102 }; // ASCII characters
const _ch = (ch) => {
    if (ch >= C._0 && ch <= C._9)
        return ch - C._0; // '2' => 50-48
    if (ch >= C.A && ch <= C.F)
        return ch - (C.A - 10); // 'B' => 66-(65-10)
    if (ch >= C.a && ch <= C.f)
        return ch - (C.a - 10); // 'b' => 98-(97-10)
    return;
};
const hexToBytes = (hex) => {
    const e = 'hex invalid';
    if (!isStr(hex))
        return err(e);
    const hl = hex.length;
    const al = hl / 2;
    if (hl % 2)
        return err(e);
    const array = u8n(al);
    for (let ai = 0, hi = 0; ai < al; ai++, hi += 2) {
        // treat each char as ASCII
        const n1 = _ch(hex.charCodeAt(hi)); // parse first char, multiply it by 16
        const n2 = _ch(hex.charCodeAt(hi + 1)); // parse second char
        if (n1 === undefined || n2 === undefined)
            return err(e);
        array[ai] = n1 * 16 + n2; // example: 'A9' => 10*16 + 9
    }
    return array;
};
/** normalize hex or ui8a to ui8a */
const toU8 = (a, len) => abytes(isStr(a) ? hexToBytes(a) : u8fr(abytes(a)), len);
const cr = () => globalThis?.crypto; // WebCrypto is available in all modern environments
const subtle = () => cr()?.subtle ?? err('crypto.subtle must be defined');
// prettier-ignore
const concatBytes = (...arrs) => {
    const r = u8n(arrs.reduce((sum, a) => sum + abytes(a).length, 0)); // create u8a of summed length
    let pad = 0; // walk through each array,
    arrs.forEach(a => { r.set(a, pad); pad += a.length; }); // ensure they have proper type
    return r;
};
/** WebCrypto OS-level CSPRNG (random number generator). Will throw when not available. */
const randomBytes = (len = L) => {
    const c = cr();
    return c.getRandomValues(u8n(len));
};
const big = BigInt;
const arange = (n, min, max, msg = 'bad number: out of range') => isBig(n) && min <= n && n < max ? n : err(msg);
/** modular division */
const M = (a, b = P) => {
    const r = a % b;
    return r >= 0n ? r : b + r;
};
const modN = (a) => M(a, N);
/** Modular inversion using eucledian GCD (non-CT). No negative exponent for now. */
// prettier-ignore
const invert = (num, md) => {
    if (num === 0n || md <= 0n)
        err('no inverse n=' + num + ' mod=' + md);
    let a = M(num, md), b = md, x = 0n, y = 1n, u = 1n, v = 0n;
    while (a !== 0n) {
        const q = b / a, r = b % a;
        const m = x - u * q, n = y - v * q;
        b = a, a = r, x = u, y = v, u = m, v = n;
    }
    return b === 1n ? M(x, md) : err('no inverse'); // b is gcd at this point
};
const callHash = (name) => {
    // @ts-ignore
    const fn = etc[name];
    if (typeof fn !== 'function')
        err('hashes.' + name + ' not set');
    return fn;
};
const apoint = (p) => (p instanceof Point ? p : err('Point expected'));
// ## End of Helpers
// -----------------
const B256 = 2n ** 256n;
/** Point in XYZT extended coordinates. */
class Point {
    static BASE;
    static ZERO;
    ex;
    ey;
    ez;
    et;
    constructor(ex, ey, ez, et) {
        const max = B256;
        this.ex = arange(ex, 0n, max);
        this.ey = arange(ey, 0n, max);
        this.ez = arange(ez, 1n, max);
        this.et = arange(et, 0n, max);
        Object.freeze(this);
    }
    static fromAffine(p) {
        return new Point(p.x, p.y, 1n, M(p.x * p.y));
    }
    /** RFC8032 5.1.3: Uint8Array to Point. */
    static fromBytes(hex, zip215 = false) {
        const d = _d;
        // Copy array to not mess it up.
        const normed = u8fr(abytes(hex, L));
        // adjust first LE byte = last BE byte
        const lastByte = hex[31];
        normed[31] = lastByte & ~0x80;
        const y = bytesToNumLE(normed);
        // zip215=true:           0 <= y < 2^256
        // zip215=false, RFC8032: 0 <= y < 2^255-19
        const max = zip215 ? B256 : P;
        arange(y, 0n, max);
        const y2 = M(y * y); // y²
        const u = M(y2 - 1n); // u=y²-1
        const v = M(d * y2 + 1n); // v=dy²+1
        let { isValid, value: x } = uvRatio(u, v); // (uv³)(uv⁷)^(p-5)/8; square root
        if (!isValid)
            err('bad point: y not sqrt'); // not square root: bad point
        const isXOdd = (x & 1n) === 1n; // adjust sign of x coordinate
        const isLastByteOdd = (lastByte & 0x80) !== 0; // x_0, last bit
        if (!zip215 && x === 0n && isLastByteOdd)
            err('bad point: x==0, isLastByteOdd'); // x=0, x_0=1
        if (isLastByteOdd !== isXOdd)
            x = M(-x);
        return new Point(x, y, 1n, M(x * y)); // Z=1, T=xy
    }
    /** Checks if the point is valid and on-curve. */
    assertValidity() {
        const a = _a;
        const d = _d;
        const p = this;
        if (p.is0())
            throw new Error('bad point: ZERO'); // TODO: optimize, with vars below?
        // Equation in affine coordinates: ax² + y² = 1 + dx²y²
        // Equation in projective coordinates (X/Z, Y/Z, Z):  (aX² + Y²)Z² = Z⁴ + dX²Y²
        const { ex: X, ey: Y, ez: Z, et: T } = p;
        const X2 = M(X * X); // X²
        const Y2 = M(Y * Y); // Y²
        const Z2 = M(Z * Z); // Z²
        const Z4 = M(Z2 * Z2); // Z⁴
        const aX2 = M(X2 * a); // aX²
        const left = M(Z2 * M(aX2 + Y2)); // (aX² + Y²)Z²
        const right = M(Z4 + M(d * M(X2 * Y2))); // Z⁴ + dX²Y²
        if (left !== right)
            throw new Error('bad point: equation left != right (1)');
        // In Extended coordinates we also have T, which is x*y=T/Z: check X*Y == Z*T
        const XY = M(X * Y);
        const ZT = M(Z * T);
        if (XY !== ZT)
            throw new Error('bad point: equation left != right (2)');
        return this;
    }
    /** Equality check: compare points P&Q. */
    equals(other) {
        const { ex: X1, ey: Y1, ez: Z1 } = this;
        const { ex: X2, ey: Y2, ez: Z2 } = apoint(other); // checks class equality
        const X1Z2 = M(X1 * Z2);
        const X2Z1 = M(X2 * Z1);
        const Y1Z2 = M(Y1 * Z2);
        const Y2Z1 = M(Y2 * Z1);
        return X1Z2 === X2Z1 && Y1Z2 === Y2Z1;
    }
    is0() {
        return this.equals(I);
    }
    /** Flip point over y coordinate. */
    negate() {
        return new Point(M(-this.ex), this.ey, this.ez, M(-this.et));
    }
    /** Point doubling. Complete formula. Cost: `4M + 4S + 1*a + 6add + 1*2`. */
    double() {
        const { ex: X1, ey: Y1, ez: Z1 } = this;
        const a = _a;
        // https://hyperelliptic.org/EFD/g1p/auto-twisted-extended.html#doubling-dbl-2008-hwcd
        const A = M(X1 * X1);
        const B = M(Y1 * Y1);
        const C = M(2n * M(Z1 * Z1));
        const D = M(a * A);
        const x1y1 = X1 + Y1;
        const E = M(M(x1y1 * x1y1) - A - B);
        const G = D + B;
        const F = G - C;
        const H = D - B;
        const X3 = M(E * F);
        const Y3 = M(G * H);
        const T3 = M(E * H);
        const Z3 = M(F * G);
        return new Point(X3, Y3, Z3, T3);
    }
    /** Point addition. Complete formula. Cost: `8M + 1*k + 8add + 1*2`. */
    add(other) {
        const { ex: X1, ey: Y1, ez: Z1, et: T1 } = this;
        const { ex: X2, ey: Y2, ez: Z2, et: T2 } = apoint(other); // doesn't check if other on-curve
        const a = _a;
        const d = _d;
        // https://hyperelliptic.org/EFD/g1p/auto-twisted-extended-1.html#addition-add-2008-hwcd-3
        const A = M(X1 * X2);
        const B = M(Y1 * Y2);
        const C = M(T1 * d * T2);
        const D = M(Z1 * Z2);
        const E = M((X1 + Y1) * (X2 + Y2) - A - B);
        const F = M(D - C);
        const G = M(D + C);
        const H = M(B - a * A);
        const X3 = M(E * F);
        const Y3 = M(G * H);
        const T3 = M(E * H);
        const Z3 = M(F * G);
        return new Point(X3, Y3, Z3, T3);
    }
    /**
     * Point-by-scalar multiplication. Scalar must be in range 1 <= n < CURVE.n.
     * Uses {@link wNAF} for base point.
     * Uses fake point to mitigate side-channel leakage.
     * @param n scalar by which point is multiplied
     * @param safe safe mode guards against timing attacks; unsafe mode is faster
     */
    multiply(n, safe = true) {
        if (!safe && (n === 0n || this.is0()))
            return I;
        arange(n, 1n, N);
        if (n === 1n)
            return this;
        if (this.equals(G))
            return wNAF(n).p;
        // init result point & fake point
        let p = I;
        let f = G;
        for (let d = this; n > 0n; d = d.double(), n >>= 1n) {
            // if bit is present, add to point
            // if not present, add to fake, for timing safety
            if (n & 1n)
                p = p.add(d);
            else if (safe)
                f = f.add(d);
        }
        return p;
    }
    /** Convert point to 2d xy affine point. (X, Y, Z) ∋ (x=X/Z, y=Y/Z) */
    toAffine() {
        const { ex: x, ey: y, ez: z } = this;
        // fast-paths for ZERO point OR Z=1
        if (this.equals(I))
            return { x: 0n, y: 1n };
        const iz = invert(z, P);
        // (Z * Z^-1) must be 1, otherwise bad math
        if (M(z * iz) !== 1n)
            err('invalid inverse');
        // x = X*Z^-1; y = Y*Z^-1
        return { x: M(x * iz), y: M(y * iz) };
    }
    toBytes() {
        const { x, y } = this.assertValidity().toAffine();
        const b = numTo32bLE(y);
        // store sign in first LE byte
        b[31] |= x & 1n ? 0x80 : 0;
        return b;
    }
    toHex() {
        return bytesToHex(this.toBytes());
    } // encode to hex string
    clearCofactor() {
        return this.multiply(big(h), false);
    }
    isSmallOrder() {
        return this.clearCofactor().is0();
    }
    isTorsionFree() {
        // multiply by big number CURVE.n
        let p = this.multiply(N / 2n, false).double(); // ensures the point is not "bad".
        if (N % 2n)
            p = p.add(this); // P^(N+1) // P*N == (P*(N/2))*2+P
        return p.is0();
    }
    static fromHex(hex, zip215) {
        return Point.fromBytes(toU8(hex), zip215);
    }
    get x() {
        return this.toAffine().x;
    }
    get y() {
        return this.toAffine().y;
    }
    toRawBytes() {
        return this.toBytes();
    }
}
/** Generator / base point */
const G = new Point(Gx, Gy, 1n, M(Gx * Gy));
/** Identity / zero point */
const I = new Point(0n, 1n, 1n, 0n);
// Static aliases
Point.BASE = G;
Point.ZERO = I;
const numTo32bLE = (num) => hexToBytes(padh(arange(num, 0n, B256), L2)).reverse();
const bytesToNumLE = (b) => big('0x' + bytesToHex(u8fr(abytes(b)).reverse()));
const pow2 = (x, power) => {
    // pow2(x, 4) == x^(2^4)
    let r = x;
    while (power-- > 0n) {
        r *= r;
        r %= P;
    }
    return r;
};
// prettier-ignore
const pow_2_252_3 = (x) => {
    const x2 = (x * x) % P; // x^2,       bits 1
    const b2 = (x2 * x) % P; // x^3,       bits 11
    const b4 = (pow2(b2, 2n) * b2) % P; // x^(2^4-1), bits 1111
    const b5 = (pow2(b4, 1n) * x) % P; // x^(2^5-1), bits 11111
    const b10 = (pow2(b5, 5n) * b5) % P; // x^(2^10)
    const b20 = (pow2(b10, 10n) * b10) % P; // x^(2^20)
    const b40 = (pow2(b20, 20n) * b20) % P; // x^(2^40)
    const b80 = (pow2(b40, 40n) * b40) % P; // x^(2^80)
    const b160 = (pow2(b80, 80n) * b80) % P; // x^(2^160)
    const b240 = (pow2(b160, 80n) * b80) % P; // x^(2^240)
    const b250 = (pow2(b240, 10n) * b10) % P; // x^(2^250)
    const pow_p_5_8 = (pow2(b250, 2n) * x) % P; // < To pow to (p+3)/8, multiply it by x.
    return { pow_p_5_8, b2 };
};
const RM1 = 0x2b8324804fc1df0b2b4d00993dfbd7a72f431806ad2fe478c4ee1b274a0ea0b0n; // √-1
// for sqrt comp
// prettier-ignore
const uvRatio = (u, v) => {
    const v3 = M(v * v * v); // v³
    const v7 = M(v3 * v3 * v); // v⁷
    const pow = pow_2_252_3(u * v7).pow_p_5_8; // (uv⁷)^(p-5)/8
    let x = M(u * v3 * pow); // (uv³)(uv⁷)^(p-5)/8
    const vx2 = M(v * x * x); // vx²
    const root1 = x; // First root candidate
    const root2 = M(x * RM1); // Second root candidate; RM1 is √-1
    const useRoot1 = vx2 === u; // If vx² = u (mod p), x is a square root
    const useRoot2 = vx2 === M(-u); // If vx² = -u, set x <-- x * 2^((p-1)/4)
    const noRoot = vx2 === M(-u * RM1); // There is no valid root, vx² = -u√-1
    if (useRoot1)
        x = root1;
    if (useRoot2 || noRoot)
        x = root2; // We return root2 anyway, for const-time
    if ((M(x) & 1n) === 1n)
        x = M(-x); // edIsNegative
    return { isValid: useRoot1 || useRoot2, value: x };
};
// N == L, just weird naming
const modL_LE = (hash) => modN(bytesToNumLE(hash)); // modulo L; but little-endian
const sha512a = (...m) => etc.sha512Async(...m); // Async SHA512
const sha512s = (...m) => callHash('sha512Sync')(...m);
// RFC8032 5.1.5
const hash2extK = (hashed) => {
    // slice creates a copy, unlike subarray
    const head = hashed.slice(0, L);
    head[0] &= 248; // Clamp bits: 0b1111_1000
    head[31] &= 127; // 0b0111_1111
    head[31] |= 64; // 0b0100_0000
    const prefix = hashed.slice(L, L2); // private key "prefix"
    const scalar = modL_LE(head); // modular division over curve order
    const point = G.multiply(scalar); // public key point
    const pointBytes = point.toBytes(); // point serialized to Uint8Array
    return { head, prefix, scalar, point, pointBytes };
};
// RFC8032 5.1.5; getPublicKey async, sync. Hash priv key and extract point.
const getExtendedPublicKeyAsync = (priv) => sha512a(toU8(priv, L)).then(hash2extK);
const getExtendedPublicKey = (priv) => hash2extK(sha512s(toU8(priv, L)));
/** Creates 32-byte ed25519 public key from 32-byte private key. Async. */
const getPublicKeyAsync = (priv) => getExtendedPublicKeyAsync(priv).then((p) => p.pointBytes);
/** Creates 32-byte ed25519 public key from 32-byte private key. To use, set `etc.sha512Sync` first. */
const getPublicKey = (priv) => getExtendedPublicKey(priv).pointBytes;
const hashFinishA = (res) => sha512a(res.hashable).then(res.finish);
const hashFinishS = (res) => res.finish(sha512s(res.hashable));
const _sign = (e, rBytes, msg) => {
    // sign() shared code
    const { pointBytes: P, scalar: s } = e;
    const r = modL_LE(rBytes); // r was created outside, reduce it modulo L
    const R = G.multiply(r).toBytes(); // R = [r]B
    const hashable = concatBytes(R, P, msg); // dom2(F, C) || R || A || PH(M)
    const finish = (hashed) => {
        // k = SHA512(dom2(F, C) || R || A || PH(M))
        const S = modN(r + modL_LE(hashed) * s); // S = (r + k * s) mod L; 0 <= s < l
        return abytes(concatBytes(R, numTo32bLE(S)), L2); // 64-byte sig: 32b R.x + 32b LE(S)
    };
    return { hashable, finish };
};
/**
 * Signs message (NOT message hash) using private key. Async.
 * Follows RFC8032 5.1.6.
 */
const signAsync = async (msg, privKey) => {
    const m = toU8(msg);
    const e = await getExtendedPublicKeyAsync(privKey);
    const rBytes = await sha512a(e.prefix, m); // r = SHA512(dom2(F, C) || prefix || PH(M))
    return hashFinishA(_sign(e, rBytes, m)); // gen R, k, S, then 64-byte signature
};
/**
 * Signs message (NOT message hash) using private key. To use, set `hashes.sha512` first.
 * Follows RFC8032 5.1.6.
 */
const sign = (msg, privKey) => {
    const m = toU8(msg);
    const e = getExtendedPublicKey(privKey);
    const rBytes = sha512s(e.prefix, m); // r = SHA512(dom2(F, C) || prefix || PH(M))
    return hashFinishS(_sign(e, rBytes, m)); // gen R, k, S, then 64-byte signature
};
const veriOpts = { zip215: true };
const _verify = (sig, msg, pub, opts = veriOpts) => {
    sig = toU8(sig, L2); // Signature hex str/Bytes, must be 64 bytes
    msg = toU8(msg); // Message hex str/Bytes
    pub = toU8(pub, L);
    const { zip215 } = opts; // switch between zip215 and rfc8032 verif
    let A;
    let R;
    let s;
    let SB;
    let hashable = Uint8Array.of();
    try {
        A = Point.fromHex(pub, zip215); // public key A decoded
        R = Point.fromHex(sig.slice(0, L), zip215); // 0 <= R < 2^256: ZIP215 R can be >= P
        s = bytesToNumLE(sig.slice(L, L2)); // Decode second half as an integer S
        SB = G.multiply(s, false); // in the range 0 <= s < L
        hashable = concatBytes(R.toBytes(), A.toBytes(), msg); // dom2(F, C) || R || A || PH(M)
    }
    catch (error) { }
    const finish = (hashed) => {
        // k = SHA512(dom2(F, C) || R || A || PH(M))
        if (SB == null)
            return false; // false if try-catch catched an error
        if (!zip215 && A.isSmallOrder())
            return false; // false for SBS: Strongly Binding Signature
        const k = modL_LE(hashed); // decode in little-endian, modulo L
        const RkA = R.add(A.multiply(k, false)); // [8]R + [8][k]A'
        return RkA.add(SB.negate()).clearCofactor().is0(); // [8][S]B = [8]R + [8][k]A'
    };
    return { hashable, finish };
};
/** Verifies signature on message and public key. Async. Follows RFC8032 5.1.7. */
const verifyAsync = async (s, m, p, opts = veriOpts) => hashFinishA(_verify(s, m, p, opts));
/** Verifies signature on message and public key. To use, set `hashes.sha512` first. Follows RFC8032 5.1.7. */
const verify = (s, m, p, opts = veriOpts) => hashFinishS(_verify(s, m, p, opts));
/** Math, hex, byte helpers. Not in `utils` because utils share API with noble-curves. */
const etc = {
    sha512Async: async (...messages) => {
        const s = subtle();
        const m = concatBytes(...messages);
        return u8n(await s.digest('SHA-512', m.buffer));
    },
    sha512Sync: undefined,
    bytesToHex: bytesToHex,
    hexToBytes: hexToBytes,
    concatBytes: concatBytes,
    mod: M,
    invert: invert,
    randomBytes: randomBytes,
};
/** ed25519-specific key utilities. */
const utils = {
    getExtendedPublicKeyAsync: getExtendedPublicKeyAsync,
    getExtendedPublicKey: getExtendedPublicKey,
    randomPrivateKey: () => randomBytes(L),
    precompute: (w = 8, p = G) => {
        p.multiply(3n);
        w;
        return p;
    }, // no-op
};
// ## Precomputes
// --------------
const W = 8; // W is window size
const scalarBits = 256;
const pwindows = Math.ceil(scalarBits / W) + 1; // 33 for W=8
const pwindowSize = 2 ** (W - 1); // 128 for W=8
const precompute = () => {
    const points = [];
    let p = G;
    let b = p;
    for (let w = 0; w < pwindows; w++) {
        b = p;
        points.push(b);
        for (let i = 1; i < pwindowSize; i++) {
            b = b.add(p);
            points.push(b);
        } // i=1, bc we skip 0
        p = b.double();
    }
    return points;
};
let Gpows = undefined; // precomputes for base point G
// const-time negate
const ctneg = (cnd, p) => {
    const n = p.negate();
    return cnd ? n : p;
};
/**
 * Precomputes give 12x faster getPublicKey(), 10x sign(), 2x verify() by
 * caching multiples of G (base point). Cache is stored in 32MB of RAM.
 * Any time `G.multiply` is done, precomputes are used.
 * Not used for getSharedSecret, which instead multiplies random pubkey `P.multiply`.
 *
 * w-ary non-adjacent form (wNAF) precomputation method is 10% slower than windowed method,
 * but takes 2x less RAM. RAM reduction is possible by utilizing `.subtract`.
 *
 * !! Precomputes can be disabled by commenting-out call of the wNAF() inside Point#multiply().
 */
const wNAF = (n) => {
    const comp = Gpows || (Gpows = precompute());
    let p = I;
    let f = G; // f must be G, or could become I in the end
    const pow_2_w = 2 ** W; // 256 for W=8
    const maxNum = pow_2_w; // 256 for W=8
    const mask = big(pow_2_w - 1); // 255 for W=8 == mask 0b11111111
    const shiftBy = big(W); // 8 for W=8
    for (let w = 0; w < pwindows; w++) {
        let wbits = Number(n & mask); // extract W bits.
        n >>= shiftBy; // shift number by W bits.
        if (wbits > pwindowSize) {
            wbits -= maxNum;
            n += 1n;
        } // split if bits > max: +224 => 256-32
        const off = w * pwindowSize;
        const offF = off; // offsets, evaluate both
        const offP = off + Math.abs(wbits) - 1;
        const isEven = w % 2 !== 0; // conditions, evaluate both
        const isNeg = wbits < 0;
        if (wbits === 0) {
            // off == I: can't add it. Adding random offF instead.
            f = f.add(ctneg(isEven, comp[offF])); // bits are 0: add garbage to fake point
        }
        else {
            p = p.add(ctneg(isNeg, comp[offP])); // bits are 1: add to result point
        }
    }
    return { p, f }; // return both real and fake points for JIT
};
// !! Remove the export to easily use in REPL / browser console
export { ed25519_CURVE as CURVE, etc, Point as ExtendedPoint, getPublicKey, getPublicKeyAsync, Point, sign, signAsync, utils, verify, verifyAsync, };