diff options
Diffstat (limited to 'crypto/src/math/ec/rfc7748/X25519Field.cs')
| -rw-r--r-- | crypto/src/math/ec/rfc7748/X25519Field.cs | 76 |
1 files changed, 69 insertions, 7 deletions
diff --git a/crypto/src/math/ec/rfc7748/X25519Field.cs b/crypto/src/math/ec/rfc7748/X25519Field.cs index 6843e274a..ffede563b 100644 --- a/crypto/src/math/ec/rfc7748/X25519Field.cs +++ b/crypto/src/math/ec/rfc7748/X25519Field.cs @@ -1,6 +1,8 @@ using System; using System.Diagnostics; +using Org.BouncyCastle.Math.Raw; + namespace Org.BouncyCastle.Math.EC.Rfc7748 { public abstract class X25519Field @@ -11,6 +13,8 @@ namespace Org.BouncyCastle.Math.EC.Rfc7748 private const int M25 = 0x01FFFFFF; private const int M26 = 0x03FFFFFF; + private static readonly uint[] P32 = new uint[]{ 0xFFFFFFEDU, 0xFFFFFFFFU, 0xFFFFFFFFU, 0xFFFFFFFFU, + 0xFFFFFFFFU, 0xFFFFFFFFU, 0xFFFFFFFFU, 0x7FFFFFFFU }; private static readonly int[] RootNegOne = { 0x020EA0B0, 0x0386C9D2, 0x00478C4E, 0x0035697F, 0x005E8630, 0x01FBD7A7, 0x0340264F, 0x01F0B2B4, 0x00027E0E, 0x00570649 }; @@ -128,6 +132,14 @@ namespace Org.BouncyCastle.Math.EC.Rfc7748 } } + [CLSCompliantAttribute(false)] + public static void Decode(uint[] x, int xOff, int[] z) + { + Decode128(x, xOff, z, 0); + Decode128(x, xOff + 4, z, 5); + z[9] &= M24; + } + public static void Decode(byte[] x, int xOff, int[] z) { Decode128(x, xOff, z, 0); @@ -135,6 +147,17 @@ namespace Org.BouncyCastle.Math.EC.Rfc7748 z[9] &= M24; } + private static void Decode128(uint[] x, int xOff, int[] z, int zOff) + { + uint t0 = x[xOff + 0], t1 = x[xOff + 1], t2 = x[xOff + 2], t3 = x[xOff + 3]; + + z[zOff + 0] = (int)t0 & M26; + z[zOff + 1] = (int)((t1 << 6) | (t0 >> 26)) & M26; + z[zOff + 2] = (int)((t2 << 12) | (t1 >> 20)) & M25; + z[zOff + 3] = (int)((t3 << 19) | (t2 >> 13)) & M26; + z[zOff + 4] = (int)(t3 >> 7); + } + private static void Decode128(byte[] bs, int off, int[] z, int zOff) { uint t0 = Decode32(bs, off + 0); @@ -158,12 +181,30 @@ namespace Org.BouncyCastle.Math.EC.Rfc7748 return n; } + [CLSCompliantAttribute(false)] + public static void Encode(int[] x, uint[] z, int zOff) + { + Encode128(x, 0, z, zOff); + Encode128(x, 5, z, zOff + 4); + } + public static void Encode(int[] x, byte[] z, int zOff) { Encode128(x, 0, z, zOff); Encode128(x, 5, z, zOff + 16); } + private static void Encode128(int[] x, int xOff, uint[] z, int zOff) + { + uint x0 = (uint)x[xOff + 0], x1 = (uint)x[xOff + 1], x2 = (uint)x[xOff + 2], x3 = (uint)x[xOff + 3], + x4 = (uint)x[xOff + 4]; + + z[zOff + 0] = x0 | (x1 << 26); + z[zOff + 1] = (x1 >> 6) | (x2 << 20); + z[zOff + 2] = (x2 >> 12) | (x3 << 13); + z[zOff + 3] = (x3 >> 19) | (x4 << 7); + } + private static void Encode128(int[] x, int xOff, byte[] bs, int off) { uint x0 = (uint)x[xOff + 0], x1 = (uint)x[xOff + 1], x2 = (uint)x[xOff + 2]; @@ -185,15 +226,36 @@ namespace Org.BouncyCastle.Math.EC.Rfc7748 public static void Inv(int[] x, int[] z) { - // z = x^(p-2) = x^7FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEB - // (250 1s) (1 0s) (1 1s) (1 0s) (2 1s) - // Addition chain: [1] [2] 3 5 10 15 25 50 75 125 [250] + //int[] x2 = Create(); + //int[] t = Create(); + //PowPm5d8(x, x2, t); + //Sqr(t, 3, t); + //Mul(t, x2, z); - int[] x2 = Create(); int[] t = Create(); - PowPm5d8(x, x2, t); - Sqr(t, 3, t); - Mul(t, x2, z); + uint[] u = new uint[8]; + + Copy(x, 0, t, 0); + Normalize(t); + Encode(t, u, 0); + + Mod.ModOddInverse(P32, u, u); + + Decode(u, 0, z); + } + + public static void InvVar(int[] x, int[] z) + { + int[] t = Create(); + uint[] u = new uint[8]; + + Copy(x, 0, t, 0); + Normalize(t); + Encode(t, u, 0); + + Mod.ModOddInverseVar(P32, u, u); + + Decode(u, 0, z); } public static int IsZero(int[] x) |