using System; using System.Diagnostics; using Org.BouncyCastle.Crypto; using Org.BouncyCastle.Crypto.Digests; using Org.BouncyCastle.Math.EC.Rfc7748; using Org.BouncyCastle.Math.Raw; using Org.BouncyCastle.Security; using Org.BouncyCastle.Utilities; namespace Org.BouncyCastle.Math.EC.Rfc8032 { public abstract class Ed25519 { // -x^2 + y^2 == 1 + 0x52036CEE2B6FFE738CC740797779E89800700A4D4141D8AB75EB4DCA135978A3 * x^2 * y^2 public enum Algorithm { Ed25519 = 0, Ed25519ctx = 1, Ed25519ph = 2, } private const long M28L = 0x0FFFFFFFL; private const long M32L = 0xFFFFFFFFL; private const int PointBytes = 32; private const int ScalarUints = 8; private const int ScalarBytes = ScalarUints * 4; public static readonly int PrehashSize = 64; public static readonly int PublicKeySize = PointBytes; public static readonly int SecretKeySize = 32; public static readonly int SignatureSize = PointBytes + ScalarBytes; private static readonly byte[] Dom2Prefix = Strings.ToByteArray("SigEd25519 no Ed25519 collisions"); private static readonly uint[] P = { 0xFFFFFFEDU, 0xFFFFFFFFU, 0xFFFFFFFFU, 0xFFFFFFFFU, 0xFFFFFFFFU, 0xFFFFFFFFU, 0xFFFFFFFFU, 0x7FFFFFFFU }; private static readonly uint[] L = { 0x5CF5D3EDU, 0x5812631AU, 0xA2F79CD6U, 0x14DEF9DEU, 0x00000000U, 0x00000000U, 0x00000000U, 0x10000000U }; private const int L0 = unchecked((int)0xFCF5D3ED); // L0:26/-- private const int L1 = 0x012631A6; // L1:24/22 private const int L2 = 0x079CD658; // L2:27/-- private const int L3 = unchecked((int)0xFF9DEA2F); // L3:23/-- private const int L4 = 0x000014DF; // L4:12/11 private static readonly int[] B_x = { 0x0325D51A, 0x018B5823, 0x007B2C95, 0x0304A92D, 0x00D2598E, 0x01D6DC5C, 0x01388C7F, 0x013FEC0A, 0x029E6B72, 0x0042D26D }; private static readonly int[] B_y = { 0x02666658, 0x01999999, 0x00666666, 0x03333333, 0x00CCCCCC, 0x02666666, 0x01999999, 0x00666666, 0x03333333, 0x00CCCCCC, }; private static readonly int[] C_d = { 0x035978A3, 0x02D37284, 0x018AB75E, 0x026A0A0E, 0x0000E014, 0x0379E898, 0x01D01E5D, 0x01E738CC, 0x03715B7F, 0x00A406D9 }; private static readonly int[] C_d2 = { 0x02B2F159, 0x01A6E509, 0x01156EBD, 0x00D4141D, 0x0001C029, 0x02F3D130, 0x03A03CBB, 0x01CE7198, 0x02E2B6FF, 0x00480DB3 }; private static readonly int[] C_d4 = { 0x0165E2B2, 0x034DCA13, 0x002ADD7A, 0x01A8283B, 0x00038052, 0x01E7A260, 0x03407977, 0x019CE331, 0x01C56DFF, 0x00901B67 }; private const int WnafWidthBase = 7; private const int PrecompBlocks = 8; private const int PrecompTeeth = 4; private const int PrecompSpacing = 8; private const int PrecompPoints = 1 << (PrecompTeeth - 1); private const int PrecompMask = PrecompPoints - 1; private static readonly object precompLock = new object(); // TODO[ed25519] Convert to PointPrecomp private static PointExt[] precompBaseTable = null; private static int[] precompBase = null; private class PointAccum { internal int[] x = X25519Field.Create(); internal int[] y = X25519Field.Create(); internal int[] z = X25519Field.Create(); internal int[] u = X25519Field.Create(); internal int[] v = X25519Field.Create(); } private class PointExt { internal int[] x = X25519Field.Create(); internal int[] y = X25519Field.Create(); internal int[] z = X25519Field.Create(); internal int[] t = X25519Field.Create(); } private class PointPrecomp { internal int[] ypx_h = X25519Field.Create(); internal int[] ymx_h = X25519Field.Create(); internal int[] xyd = X25519Field.Create(); } private static byte[] CalculateS(byte[] r, byte[] k, byte[] s) { uint[] t = new uint[ScalarUints * 2]; DecodeScalar(r, 0, t); uint[] u = new uint[ScalarUints]; DecodeScalar(k, 0, u); uint[] v = new uint[ScalarUints]; DecodeScalar(s, 0, v); Nat256.MulAddTo(u, v, t); byte[] result = new byte[ScalarBytes * 2]; for (int i = 0; i < t.Length; ++i) { Encode32(t[i], result, i * 4); } return ReduceScalar(result); } private static bool CheckContextVar(byte[] ctx, byte phflag) { return ctx == null && phflag == 0x00 || ctx != null && ctx.Length < 256; } private static int CheckPoint(int[] x, int[] y) { int[] t = X25519Field.Create(); int[] u = X25519Field.Create(); int[] v = X25519Field.Create(); X25519Field.Sqr(x, u); X25519Field.Sqr(y, v); X25519Field.Mul(u, v, t); X25519Field.Sub(v, u, v); X25519Field.Mul(t, C_d, t); X25519Field.AddOne(t); X25519Field.Sub(t, v, t); X25519Field.Normalize(t); return X25519Field.IsZero(t); } private static int CheckPoint(int[] x, int[] y, int[] z) { int[] t = X25519Field.Create(); int[] u = X25519Field.Create(); int[] v = X25519Field.Create(); int[] w = X25519Field.Create(); X25519Field.Sqr(x, u); X25519Field.Sqr(y, v); X25519Field.Sqr(z, w); X25519Field.Mul(u, v, t); X25519Field.Sub(v, u, v); X25519Field.Mul(v, w, v); X25519Field.Sqr(w, w); X25519Field.Mul(t, C_d, t); X25519Field.Add(t, w, t); X25519Field.Sub(t, v, t); X25519Field.Normalize(t); return X25519Field.IsZero(t); } private static bool CheckPointVar(byte[] p) { uint[] t = new uint[8]; Decode32(p, 0, t, 0, 8); t[7] &= 0x7FFFFFFFU; return !Nat256.Gte(t, P); } private static bool CheckScalarVar(byte[] s) { uint[] n = new uint[ScalarUints]; DecodeScalar(s, 0, n); return !Nat256.Gte(n, L); } private static IDigest CreateDigest() { return new Sha512Digest(); } public static IDigest CreatePrehash() { return CreateDigest(); } private static uint Decode24(byte[] bs, int off) { uint n = bs[off]; n |= (uint)bs[++off] << 8; n |= (uint)bs[++off] << 16; return n; } private static uint Decode32(byte[] bs, int off) { uint n = bs[off]; n |= (uint)bs[++off] << 8; n |= (uint)bs[++off] << 16; n |= (uint)bs[++off] << 24; return n; } private static void Decode32(byte[] bs, int bsOff, uint[] n, int nOff, int nLen) { for (int i = 0; i < nLen; ++i) { n[nOff + i] = Decode32(bs, bsOff + i * 4); } } private static bool DecodePointVar(byte[] p, int pOff, bool negate, PointExt r) { byte[] py = Arrays.CopyOfRange(p, pOff, pOff + PointBytes); if (!CheckPointVar(py)) return false; int x_0 = (py[PointBytes - 1] & 0x80) >> 7; py[PointBytes - 1] &= 0x7F; X25519Field.Decode(py, 0, r.y); int[] u = X25519Field.Create(); int[] v = X25519Field.Create(); X25519Field.Sqr(r.y, u); X25519Field.Mul(C_d, u, v); X25519Field.SubOne(u); X25519Field.AddOne(v); if (!X25519Field.SqrtRatioVar(u, v, r.x)) return false; X25519Field.Normalize(r.x); if (x_0 == 1 && X25519Field.IsZeroVar(r.x)) return false; if (negate ^ (x_0 != (r.x[0] & 1))) { X25519Field.Negate(r.x, r.x); } PointExtendXY(r); return true; } private static void DecodeScalar(byte[] k, int kOff, uint[] n) { Decode32(k, kOff, n, 0, ScalarUints); } private static void Dom2(IDigest d, byte phflag, byte[] ctx) { if (ctx != null) { d.BlockUpdate(Dom2Prefix, 0, Dom2Prefix.Length); d.Update(phflag); d.Update((byte)ctx.Length); d.BlockUpdate(ctx, 0, ctx.Length); } } private static void Encode24(uint n, byte[] bs, int off) { bs[off] = (byte)(n); bs[++off] = (byte)(n >> 8); bs[++off] = (byte)(n >> 16); } private static void Encode32(uint n, byte[] bs, int off) { bs[off] = (byte)(n); bs[++off] = (byte)(n >> 8); bs[++off] = (byte)(n >> 16); bs[++off] = (byte)(n >> 24); } private static void Encode56(ulong n, byte[] bs, int off) { Encode32((uint)n, bs, off); Encode24((uint)(n >> 32), bs, off + 4); } private static int EncodePoint(PointAccum p, byte[] r, int rOff) { int[] x = X25519Field.Create(); int[] y = X25519Field.Create(); X25519Field.Inv(p.z, y); X25519Field.Mul(p.x, y, x); X25519Field.Mul(p.y, y, y); X25519Field.Normalize(x); X25519Field.Normalize(y); int result = CheckPoint(x, y); X25519Field.Encode(y, r, rOff); r[rOff + PointBytes - 1] |= (byte)((x[0] & 1) << 7); return result; } public static void GeneratePrivateKey(SecureRandom random, byte[] k) { random.NextBytes(k); } public static void GeneratePublicKey(byte[] sk, int skOff, byte[] pk, int pkOff) { IDigest d = CreateDigest(); byte[] h = new byte[d.GetDigestSize()]; d.BlockUpdate(sk, skOff, SecretKeySize); d.DoFinal(h, 0); byte[] s = new byte[ScalarBytes]; PruneScalar(h, 0, s); ScalarMultBaseEncoded(s, pk, pkOff); } private static sbyte[] GetWnaf(uint[] n, int width) { Debug.Assert(n[ScalarUints - 1] >> 28 == 0); uint[] t = new uint[ScalarUints * 2]; { uint c = 0; int tPos = t.Length, i = ScalarUints; while (--i >= 0) { uint next = n[i]; t[--tPos] = (next >> 16) | (c << 16); t[--tPos] = c = next; } } sbyte[] ws = new sbyte[253]; uint pow2 = 1U << width; uint mask = pow2 - 1U; uint sign = pow2 >> 1; uint carry = 0U; int j = 0; for (int i = 0; i < t.Length; ++i, j -= 16) { uint word = t[i]; while (j < 16) { uint word16 = word >> j; uint bit = word16 & 1U; if (bit == carry) { ++j; continue; } uint digit = (word16 & mask) + carry; carry = digit & sign; digit -= (carry << 1); carry >>= (width - 1); ws[(i << 4) + j] = (sbyte)digit; j += width; } } Debug.Assert(carry == 0); return ws; } private static void ImplSign(IDigest d, byte[] h, byte[] s, byte[] pk, int pkOff, byte[] ctx, byte phflag, byte[] m, int mOff, int mLen, byte[] sig, int sigOff) { Dom2(d, phflag, ctx); d.BlockUpdate(h, ScalarBytes, ScalarBytes); d.BlockUpdate(m, mOff, mLen); d.DoFinal(h, 0); byte[] r = ReduceScalar(h); byte[] R = new byte[PointBytes]; ScalarMultBaseEncoded(r, R, 0); Dom2(d, phflag, ctx); d.BlockUpdate(R, 0, PointBytes); d.BlockUpdate(pk, pkOff, PointBytes); d.BlockUpdate(m, mOff, mLen); d.DoFinal(h, 0); byte[] k = ReduceScalar(h); byte[] S = CalculateS(r, k, s); Array.Copy(R, 0, sig, sigOff, PointBytes); Array.Copy(S, 0, sig, sigOff + PointBytes, ScalarBytes); } private static void ImplSign(byte[] sk, int skOff, byte[] ctx, byte phflag, byte[] m, int mOff, int mLen, byte[] sig, int sigOff) { if (!CheckContextVar(ctx, phflag)) throw new ArgumentException("ctx"); IDigest d = CreateDigest(); byte[] h = new byte[d.GetDigestSize()]; d.BlockUpdate(sk, skOff, SecretKeySize); d.DoFinal(h, 0); byte[] s = new byte[ScalarBytes]; PruneScalar(h, 0, s); byte[] pk = new byte[PointBytes]; ScalarMultBaseEncoded(s, pk, 0); ImplSign(d, h, s, pk, 0, ctx, phflag, m, mOff, mLen, sig, sigOff); } private static void ImplSign(byte[] sk, int skOff, byte[] pk, int pkOff, byte[] ctx, byte phflag, byte[] m, int mOff, int mLen, byte[] sig, int sigOff) { if (!CheckContextVar(ctx, phflag)) throw new ArgumentException("ctx"); IDigest d = CreateDigest(); byte[] h = new byte[d.GetDigestSize()]; d.BlockUpdate(sk, skOff, SecretKeySize); d.DoFinal(h, 0); byte[] s = new byte[ScalarBytes]; PruneScalar(h, 0, s); ImplSign(d, h, s, pk, pkOff, ctx, phflag, m, mOff, mLen, sig, sigOff); } private static bool ImplVerify(byte[] sig, int sigOff, byte[] pk, int pkOff, byte[] ctx, byte phflag, byte[] m, int mOff, int mLen) { if (!CheckContextVar(ctx, phflag)) throw new ArgumentException("ctx"); byte[] R = Arrays.CopyOfRange(sig, sigOff, sigOff + PointBytes); byte[] S = Arrays.CopyOfRange(sig, sigOff + PointBytes, sigOff + SignatureSize); if (!CheckPointVar(R)) return false; if (!CheckScalarVar(S)) return false; PointExt pA = new PointExt(); if (!DecodePointVar(pk, pkOff, true, pA)) return false; IDigest d = CreateDigest(); byte[] h = new byte[d.GetDigestSize()]; Dom2(d, phflag, ctx); d.BlockUpdate(R, 0, PointBytes); d.BlockUpdate(pk, pkOff, PointBytes); d.BlockUpdate(m, mOff, mLen); d.DoFinal(h, 0); byte[] k = ReduceScalar(h); uint[] nS = new uint[ScalarUints]; DecodeScalar(S, 0, nS); uint[] nA = new uint[ScalarUints]; DecodeScalar(k, 0, nA); PointAccum pR = new PointAccum(); ScalarMultStrausVar(nS, nA, pA, pR); byte[] check = new byte[PointBytes]; return 0 != EncodePoint(pR, check, 0) && Arrays.AreEqual(check, R); } private static void PointAddVar(bool negate, PointExt p, PointAccum r) { int[] A = X25519Field.Create(); int[] B = X25519Field.Create(); int[] C = X25519Field.Create(); int[] D = X25519Field.Create(); int[] E = r.u; int[] F = X25519Field.Create(); int[] G = X25519Field.Create(); int[] H = r.v; int[] c, d, f, g; if (negate) { c = D; d = C; f = G; g = F; } else { c = C; d = D; f = F; g = G; } X25519Field.Apm(r.y, r.x, B, A); X25519Field.Apm(p.y, p.x, d, c); X25519Field.Mul(A, C, A); X25519Field.Mul(B, D, B); X25519Field.Mul(r.u, r.v, C); X25519Field.Mul(C, p.t, C); X25519Field.Mul(C, C_d2, C); X25519Field.Mul(r.z, p.z, D); X25519Field.Add(D, D, D); X25519Field.Apm(B, A, H, E); X25519Field.Apm(D, C, g, f); X25519Field.Carry(g); X25519Field.Mul(E, F, r.x); X25519Field.Mul(G, H, r.y); X25519Field.Mul(F, G, r.z); } private static void PointAddVar(bool negate, PointExt p, PointExt q, PointExt r) { int[] A = X25519Field.Create(); int[] B = X25519Field.Create(); int[] C = X25519Field.Create(); int[] D = X25519Field.Create(); int[] E = X25519Field.Create(); int[] F = X25519Field.Create(); int[] G = X25519Field.Create(); int[] H = X25519Field.Create(); int[] c, d, f, g; if (negate) { c = D; d = C; f = G; g = F; } else { c = C; d = D; f = F; g = G; } X25519Field.Apm(p.y, p.x, B, A); X25519Field.Apm(q.y, q.x, d, c); X25519Field.Mul(A, C, A); X25519Field.Mul(B, D, B); X25519Field.Mul(p.t, q.t, C); X25519Field.Mul(C, C_d2, C); X25519Field.Mul(p.z, q.z, D); X25519Field.Add(D, D, D); X25519Field.Apm(B, A, H, E); X25519Field.Apm(D, C, g, f); X25519Field.Carry(g); X25519Field.Mul(E, F, r.x); X25519Field.Mul(G, H, r.y); X25519Field.Mul(F, G, r.z); X25519Field.Mul(E, H, r.t); } private static void PointAddPrecomp(PointPrecomp p, PointAccum r) { int[] A = X25519Field.Create(); int[] B = X25519Field.Create(); int[] C = X25519Field.Create(); int[] E = r.u; int[] F = X25519Field.Create(); int[] G = X25519Field.Create(); int[] H = r.v; X25519Field.Apm(r.y, r.x, B, A); X25519Field.Mul(A, p.ymx_h, A); X25519Field.Mul(B, p.ypx_h, B); X25519Field.Mul(r.u, r.v, C); X25519Field.Mul(C, p.xyd, C); X25519Field.Apm(B, A, H, E); X25519Field.Apm(r.z, C, G, F); X25519Field.Carry(G); X25519Field.Mul(E, F, r.x); X25519Field.Mul(G, H, r.y); X25519Field.Mul(F, G, r.z); } private static PointExt PointCopy(PointAccum p) { PointExt r = new PointExt(); X25519Field.Copy(p.x, 0, r.x, 0); X25519Field.Copy(p.y, 0, r.y, 0); X25519Field.Copy(p.z, 0, r.z, 0); X25519Field.Mul(p.u, p.v, r.t); return r; } private static PointExt PointCopy(PointExt p) { PointExt r = new PointExt(); X25519Field.Copy(p.x, 0, r.x, 0); X25519Field.Copy(p.y, 0, r.y, 0); X25519Field.Copy(p.z, 0, r.z, 0); X25519Field.Copy(p.t, 0, r.t, 0); return r; } private static void PointDouble(PointAccum r) { int[] A = X25519Field.Create(); int[] B = X25519Field.Create(); int[] C = X25519Field.Create(); int[] E = r.u; int[] F = X25519Field.Create(); int[] G = X25519Field.Create(); int[] H = r.v; X25519Field.Sqr(r.x, A); X25519Field.Sqr(r.y, B); X25519Field.Sqr(r.z, C); X25519Field.Add(C, C, C); X25519Field.Apm(A, B, H, G); X25519Field.Add(r.x, r.y, E); X25519Field.Sqr(E, E); X25519Field.Sub(H, E, E); X25519Field.Add(C, G, F); X25519Field.Carry(F); X25519Field.Mul(E, F, r.x); X25519Field.Mul(G, H, r.y); X25519Field.Mul(F, G, r.z); } private static void PointExtendXY(PointAccum p) { X25519Field.One(p.z); X25519Field.Copy(p.x, 0, p.u, 0); X25519Field.Copy(p.y, 0, p.v, 0); } private static void PointExtendXY(PointExt p) { X25519Field.One(p.z); X25519Field.Mul(p.x, p.y, p.t); } private static void PointLookup(int block, int index, PointPrecomp p) { Debug.Assert(0 <= block && block < PrecompBlocks); Debug.Assert(0 <= index && index < PrecompPoints); int off = block * PrecompPoints * 3 * X25519Field.Size; for (int i = 0; i < PrecompPoints; ++i) { int cond = ((i ^ index) - 1) >> 31; X25519Field.CMov(cond, precompBase, off, p.ypx_h, 0); off += X25519Field.Size; X25519Field.CMov(cond, precompBase, off, p.ymx_h, 0); off += X25519Field.Size; X25519Field.CMov(cond, precompBase, off, p.xyd, 0); off += X25519Field.Size; } } private static PointExt[] PointPrecompVar(PointExt p, int count) { Debug.Assert(count > 0); PointExt d = new PointExt(); PointAddVar(false, p, p, d); PointExt[] table = new PointExt[count]; table[0] = PointCopy(p); for (int i = 1; i < count; ++i) { PointAddVar(false, table[i - 1], d, table[i] = new PointExt()); } return table; } private static void PointSetNeutral(PointAccum p) { X25519Field.Zero(p.x); X25519Field.One(p.y); X25519Field.One(p.z); X25519Field.Zero(p.u); X25519Field.One(p.v); } private static void PointSetNeutral(PointExt p) { X25519Field.Zero(p.x); X25519Field.One(p.y); X25519Field.One(p.z); X25519Field.Zero(p.t); } public static void Precompute() { lock (precompLock) { if (precompBase != null) return; // Precomputed table for the base point in verification ladder { PointExt b = new PointExt(); X25519Field.Copy(B_x, 0, b.x, 0); X25519Field.Copy(B_y, 0, b.y, 0); PointExtendXY(b); precompBaseTable = PointPrecompVar(b, 1 << (WnafWidthBase - 2)); } PointAccum p = new PointAccum(); X25519Field.Copy(B_x, 0, p.x, 0); X25519Field.Copy(B_y, 0, p.y, 0); PointExtendXY(p); precompBase = new int[PrecompBlocks * PrecompPoints * 3 * X25519Field.Size]; int off = 0; for (int b = 0; b < PrecompBlocks; ++b) { PointExt[] ds = new PointExt[PrecompTeeth]; PointExt sum = new PointExt(); PointSetNeutral(sum); for (int t = 0; t < PrecompTeeth; ++t) { PointExt q = PointCopy(p); PointAddVar(true, sum, q, sum); PointDouble(p); ds[t] = PointCopy(p); if (b + t != PrecompBlocks + PrecompTeeth - 2) { for (int s = 1; s < PrecompSpacing; ++s) { PointDouble(p); } } } PointExt[] points = new PointExt[PrecompPoints]; int k = 0; points[k++] = sum; for (int t = 0; t < (PrecompTeeth - 1); ++t) { int size = 1 << t; for (int j = 0; j < size; ++j, ++k) { PointAddVar(false, points[k - size], ds[t], points[k] = new PointExt()); } } Debug.Assert(k == PrecompPoints); for (int i = 0; i < PrecompPoints; ++i) { PointExt q = points[i]; int[] x = X25519Field.Create(); int[] y = X25519Field.Create(); X25519Field.Add(q.z, q.z, x); // TODO[ed25519] Batch inversion X25519Field.Inv(x, y); X25519Field.Mul(q.x, y, x); X25519Field.Mul(q.y, y, y); PointPrecomp r = new PointPrecomp(); X25519Field.Apm(y, x, r.ypx_h, r.ymx_h); X25519Field.Mul(x, y, r.xyd); X25519Field.Mul(r.xyd, C_d4, r.xyd); X25519Field.Normalize(r.ypx_h); X25519Field.Normalize(r.ymx_h); //X25519Field.Normalize(r.xyd); X25519Field.Copy(r.ypx_h, 0, precompBase, off); off += X25519Field.Size; X25519Field.Copy(r.ymx_h, 0, precompBase, off); off += X25519Field.Size; X25519Field.Copy(r.xyd, 0, precompBase, off); off += X25519Field.Size; } } Debug.Assert(off == precompBase.Length); } } private static void PruneScalar(byte[] n, int nOff, byte[] r) { Array.Copy(n, nOff, r, 0, ScalarBytes); r[0] &= 0xF8; r[ScalarBytes - 1] &= 0x7F; r[ScalarBytes - 1] |= 0x40; } private static byte[] ReduceScalar(byte[] n) { long x00 = Decode32(n, 0) & M32L; // x00:32/-- long x01 = (Decode24(n, 4) << 4) & M32L; // x01:28/-- long x02 = Decode32(n, 7) & M32L; // x02:32/-- long x03 = (Decode24(n, 11) << 4) & M32L; // x03:28/-- long x04 = Decode32(n, 14) & M32L; // x04:32/-- long x05 = (Decode24(n, 18) << 4) & M32L; // x05:28/-- long x06 = Decode32(n, 21) & M32L; // x06:32/-- long x07 = (Decode24(n, 25) << 4) & M32L; // x07:28/-- long x08 = Decode32(n, 28) & M32L; // x08:32/-- long x09 = (Decode24(n, 32) << 4) & M32L; // x09:28/-- long x10 = Decode32(n, 35) & M32L; // x10:32/-- long x11 = (Decode24(n, 39) << 4) & M32L; // x11:28/-- long x12 = Decode32(n, 42) & M32L; // x12:32/-- long x13 = (Decode24(n, 46) << 4) & M32L; // x13:28/-- long x14 = Decode32(n, 49) & M32L; // x14:32/-- long x15 = (Decode24(n, 53) << 4) & M32L; // x15:28/-- long x16 = Decode32(n, 56) & M32L; // x16:32/-- long x17 = (Decode24(n, 60) << 4) & M32L; // x17:28/-- long x18 = n[63] & 0xFFL; // x18:08/-- long t; //x18 += (x17 >> 28); x17 &= M28L; x09 -= x18 * L0; // x09:34/28 x10 -= x18 * L1; // x10:33/30 x11 -= x18 * L2; // x11:35/28 x12 -= x18 * L3; // x12:32/31 x13 -= x18 * L4; // x13:28/21 x17 += (x16 >> 28); x16 &= M28L; // x17:28/--, x16:28/-- x08 -= x17 * L0; // x08:54/32 x09 -= x17 * L1; // x09:52/51 x10 -= x17 * L2; // x10:55/34 x11 -= x17 * L3; // x11:51/36 x12 -= x17 * L4; // x12:41/-- //x16 += (x15 >> 28); x15 &= M28L; x07 -= x16 * L0; // x07:54/28 x08 -= x16 * L1; // x08:54/53 x09 -= x16 * L2; // x09:55/53 x10 -= x16 * L3; // x10:55/52 x11 -= x16 * L4; // x11:51/41 x15 += (x14 >> 28); x14 &= M28L; // x15:28/--, x14:28/-- x06 -= x15 * L0; // x06:54/32 x07 -= x15 * L1; // x07:54/53 x08 -= x15 * L2; // x08:56/-- x09 -= x15 * L3; // x09:55/54 x10 -= x15 * L4; // x10:55/53 //x14 += (x13 >> 28); x13 &= M28L; x05 -= x14 * L0; // x05:54/28 x06 -= x14 * L1; // x06:54/53 x07 -= x14 * L2; // x07:56/-- x08 -= x14 * L3; // x08:56/51 x09 -= x14 * L4; // x09:56/-- x13 += (x12 >> 28); x12 &= M28L; // x13:28/22, x12:28/-- x04 -= x13 * L0; // x04:54/49 x05 -= x13 * L1; // x05:54/53 x06 -= x13 * L2; // x06:56/-- x07 -= x13 * L3; // x07:56/52 x08 -= x13 * L4; // x08:56/52 x12 += (x11 >> 28); x11 &= M28L; // x12:28/24, x11:28/-- x03 -= x12 * L0; // x03:54/49 x04 -= x12 * L1; // x04:54/51 x05 -= x12 * L2; // x05:56/-- x06 -= x12 * L3; // x06:56/52 x07 -= x12 * L4; // x07:56/53 x11 += (x10 >> 28); x10 &= M28L; // x11:29/--, x10:28/-- x02 -= x11 * L0; // x02:55/32 x03 -= x11 * L1; // x03:55/-- x04 -= x11 * L2; // x04:56/55 x05 -= x11 * L3; // x05:56/52 x06 -= x11 * L4; // x06:56/53 x10 += (x09 >> 28); x09 &= M28L; // x10:29/--, x09:28/-- x01 -= x10 * L0; // x01:55/28 x02 -= x10 * L1; // x02:55/54 x03 -= x10 * L2; // x03:56/55 x04 -= x10 * L3; // x04:57/-- x05 -= x10 * L4; // x05:56/53 x08 += (x07 >> 28); x07 &= M28L; // x08:56/53, x07:28/-- x09 += (x08 >> 28); x08 &= M28L; // x09:29/25, x08:28/-- t = (x08 >> 27) & 1L; x09 += t; // x09:29/26 x00 -= x09 * L0; // x00:55/53 x01 -= x09 * L1; // x01:55/54 x02 -= x09 * L2; // x02:57/-- x03 -= x09 * L3; // x03:57/-- x04 -= x09 * L4; // x04:57/42 x01 += (x00 >> 28); x00 &= M28L; x02 += (x01 >> 28); x01 &= M28L; x03 += (x02 >> 28); x02 &= M28L; x04 += (x03 >> 28); x03 &= M28L; x05 += (x04 >> 28); x04 &= M28L; x06 += (x05 >> 28); x05 &= M28L; x07 += (x06 >> 28); x06 &= M28L; x08 += (x07 >> 28); x07 &= M28L; x09 = (x08 >> 28); x08 &= M28L; x09 -= t; Debug.Assert(x09 == 0L || x09 == -1L); x00 += x09 & L0; x01 += x09 & L1; x02 += x09 & L2; x03 += x09 & L3; x04 += x09 & L4; x01 += (x00 >> 28); x00 &= M28L; x02 += (x01 >> 28); x01 &= M28L; x03 += (x02 >> 28); x02 &= M28L; x04 += (x03 >> 28); x03 &= M28L; x05 += (x04 >> 28); x04 &= M28L; x06 += (x05 >> 28); x05 &= M28L; x07 += (x06 >> 28); x06 &= M28L; x08 += (x07 >> 28); x07 &= M28L; byte[] r = new byte[ScalarBytes]; Encode56((ulong)(x00 | (x01 << 28)), r, 0); Encode56((ulong)(x02 | (x03 << 28)), r, 7); Encode56((ulong)(x04 | (x05 << 28)), r, 14); Encode56((ulong)(x06 | (x07 << 28)), r, 21); Encode32((uint)x08, r, 28); return r; } private static void ScalarMultBase(byte[] k, PointAccum r) { Precompute(); PointSetNeutral(r); uint[] n = new uint[ScalarUints]; DecodeScalar(k, 0, n); // Recode the scalar into signed-digit form, then group comb bits in each block { uint c1 = Nat.CAdd(ScalarUints, ~(int)n[0] & 1, n, L, n); Debug.Assert(c1 == 0); uint c2 = Nat.ShiftDownBit(ScalarUints, n, 1U); Debug.Assert(c2 == (1U << 31)); for (int i = 0; i < ScalarUints; ++i) { n[i] = Interleave.Shuffle2(n[i]); } } PointPrecomp p = new PointPrecomp(); int cOff = (PrecompSpacing - 1) * PrecompTeeth; for (; ; ) { for (int b = 0; b < PrecompBlocks; ++b) { uint w = n[b] >> cOff; int sign = (int)(w >> (PrecompTeeth - 1)) & 1; int abs = ((int)w ^ -sign) & PrecompMask; Debug.Assert(sign == 0 || sign == 1); Debug.Assert(0 <= abs && abs < PrecompPoints); PointLookup(b, abs, p); X25519Field.CSwap(sign, p.ypx_h, p.ymx_h); X25519Field.CNegate(sign, p.xyd); PointAddPrecomp(p, r); } if ((cOff -= PrecompTeeth) < 0) break; PointDouble(r); } } private static void ScalarMultBaseEncoded(byte[] k, byte[] r, int rOff) { PointAccum p = new PointAccum(); ScalarMultBase(k, p); if (0 == EncodePoint(p, r, rOff)) throw new InvalidOperationException(); } internal static void ScalarMultBaseYZ(byte[] k, int kOff, int[] y, int[] z) { byte[] n = new byte[ScalarBytes]; PruneScalar(k, kOff, n); PointAccum p = new PointAccum(); ScalarMultBase(n, p); if (0 == CheckPoint(p.x, p.y, p.z)) throw new InvalidOperationException(); X25519Field.Copy(p.y, 0, y, 0); X25519Field.Copy(p.z, 0, z, 0); } private static void ScalarMultStrausVar(uint[] nb, uint[] np, PointExt p, PointAccum r) { Precompute(); int width = 5; sbyte[] ws_b = GetWnaf(nb, WnafWidthBase); sbyte[] ws_p = GetWnaf(np, width); PointExt[] tp = PointPrecompVar(p, 1 << (width - 2)); PointSetNeutral(r); for (int bit = 252;;) { int wb = ws_b[bit]; if (wb != 0) { int sign = wb >> 31; int index = (wb ^ sign) >> 1; PointAddVar((sign != 0), precompBaseTable[index], r); } int wp = ws_p[bit]; if (wp != 0) { int sign = wp >> 31; int index = (wp ^ sign) >> 1; PointAddVar((sign != 0), tp[index], r); } if (--bit < 0) break; PointDouble(r); } } public static void Sign(byte[] sk, int skOff, byte[] m, int mOff, int mLen, byte[] sig, int sigOff) { byte[] ctx = null; byte phflag = 0x00; ImplSign(sk, skOff, ctx, phflag, m, mOff, mLen, sig, sigOff); } public static void Sign(byte[] sk, int skOff, byte[] pk, int pkOff, byte[] m, int mOff, int mLen, byte[] sig, int sigOff) { byte[] ctx = null; byte phflag = 0x00; ImplSign(sk, skOff, pk, pkOff, ctx, phflag, m, mOff, mLen, sig, sigOff); } public static void Sign(byte[] sk, int skOff, byte[] ctx, byte[] m, int mOff, int mLen, byte[] sig, int sigOff) { byte phflag = 0x00; ImplSign(sk, skOff, ctx, phflag, m, mOff, mLen, sig, sigOff); } public static void Sign(byte[] sk, int skOff, byte[] pk, int pkOff, byte[] ctx, byte[] m, int mOff, int mLen, byte[] sig, int sigOff) { byte phflag = 0x00; ImplSign(sk, skOff, pk, pkOff, ctx, phflag, m, mOff, mLen, sig, sigOff); } public static void SignPrehash(byte[] sk, int skOff, byte[] ctx, byte[] ph, int phOff, byte[] sig, int sigOff) { byte phflag = 0x01; ImplSign(sk, skOff, ctx, phflag, ph, phOff, PrehashSize, sig, sigOff); } public static void SignPrehash(byte[] sk, int skOff, byte[] pk, int pkOff, byte[] ctx, byte[] ph, int phOff, byte[] sig, int sigOff) { byte phflag = 0x01; ImplSign(sk, skOff, pk, pkOff, ctx, phflag, ph, phOff, PrehashSize, sig, sigOff); } public static void SignPrehash(byte[] sk, int skOff, byte[] ctx, IDigest ph, byte[] sig, int sigOff) { byte[] m = new byte[PrehashSize]; if (PrehashSize != ph.DoFinal(m, 0)) throw new ArgumentException("ph"); byte phflag = 0x01; ImplSign(sk, skOff, ctx, phflag, m, 0, m.Length, sig, sigOff); } public static void SignPrehash(byte[] sk, int skOff, byte[] pk, int pkOff, byte[] ctx, IDigest ph, byte[] sig, int sigOff) { byte[] m = new byte[PrehashSize]; if (PrehashSize != ph.DoFinal(m, 0)) throw new ArgumentException("ph"); byte phflag = 0x01; ImplSign(sk, skOff, pk, pkOff, ctx, phflag, m, 0, m.Length, sig, sigOff); } public static bool Verify(byte[] sig, int sigOff, byte[] pk, int pkOff, byte[] m, int mOff, int mLen) { byte[] ctx = null; byte phflag = 0x00; return ImplVerify(sig, sigOff, pk, pkOff, ctx, phflag, m, mOff, mLen); } public static bool Verify(byte[] sig, int sigOff, byte[] pk, int pkOff, byte[] ctx, byte[] m, int mOff, int mLen) { byte phflag = 0x00; return ImplVerify(sig, sigOff, pk, pkOff, ctx, phflag, m, mOff, mLen); } public static bool VerifyPrehash(byte[] sig, int sigOff, byte[] pk, int pkOff, byte[] ctx, byte[] ph, int phOff) { byte phflag = 0x01; return ImplVerify(sig, sigOff, pk, pkOff, ctx, phflag, ph, phOff, PrehashSize); } public static bool VerifyPrehash(byte[] sig, int sigOff, byte[] pk, int pkOff, byte[] ctx, IDigest ph) { byte[] m = new byte[PrehashSize]; if (PrehashSize != ph.DoFinal(m, 0)) throw new ArgumentException("ph"); byte phflag = 0x01; return ImplVerify(sig, sigOff, pk, pkOff, ctx, phflag, m, 0, m.Length); } } }