diff options
Diffstat (limited to 'crypto/src/math/ec/custom/sec/SecP160R2Field.cs')
| -rw-r--r-- | crypto/src/math/ec/custom/sec/SecP160R2Field.cs | 111 |
1 files changed, 106 insertions, 5 deletions
diff --git a/crypto/src/math/ec/custom/sec/SecP160R2Field.cs b/crypto/src/math/ec/custom/sec/SecP160R2Field.cs index 1bef32eea..bc36d9de1 100644 --- a/crypto/src/math/ec/custom/sec/SecP160R2Field.cs +++ b/crypto/src/math/ec/custom/sec/SecP160R2Field.cs @@ -1,7 +1,9 @@ using System; using System.Diagnostics; +using Org.BouncyCastle.Crypto.Utilities; using Org.BouncyCastle.Math.Raw; +using Org.BouncyCastle.Security; namespace Org.BouncyCastle.Math.EC.Custom.Sec { @@ -9,10 +11,10 @@ namespace Org.BouncyCastle.Math.EC.Custom.Sec { // 2^160 - 2^32 - 2^14 - 2^12 - 2^9 - 2^8 - 2^7 - 2^3 - 2^2 - 1 internal static readonly uint[] P = new uint[]{ 0xFFFFAC73, 0xFFFFFFFE, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF }; - internal static readonly uint[] PExt = new uint[]{ 0x1B44BBA9, 0x0000A71A, 0x00000001, 0x00000000, 0x00000000, + private static readonly uint[] PExt = new uint[]{ 0x1B44BBA9, 0x0000A71A, 0x00000001, 0x00000000, 0x00000000, 0xFFFF58E6, 0xFFFFFFFD, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF }; - private static readonly uint[] PExtInv = new uint[]{ 0xE4BB4457, 0xFFFF58E5, 0xFFFFFFFE, 0xFFFFFFFF, 0xFFFFFFFF, - 0x0000A719, 0x00000002 }; + private static readonly uint[] PExtInv = new uint[]{ 0xE4BB4457, 0xFFFF58E5, 0xFFFFFFFE, 0xFFFFFFFF, + 0xFFFFFFFF, 0x0000A719, 0x00000002 }; private const uint P4 = 0xFFFFFFFF; private const uint PExt9 = 0xFFFFFFFF; private const uint PInv33 = 0x538D; @@ -70,6 +72,85 @@ namespace Org.BouncyCastle.Math.EC.Custom.Sec } } + public static void Inv(uint[] x, uint[] z) + { + /* + * Raise this element to the exponent 2^160 - 2^32 - 2^14 - 2^12 - 2^9 - 2^8 - 2^7 - 2^3 - 2^2 - 3 + * + * Breaking up the exponent's binary representation into "repunits", we get: + * { 127 1s } { 1 0s } { 17 1s } "010110001110001" + * + * Therefore we need an addition chain containing 1, 2, 3, 17, 127 (the lengths of the repunits) + * We use: 1, 2, 3, 6, 12, 15, [17], 34, 68, 102, 119, 125, [127] + */ + + if (0 != IsZero(x)) + throw new ArgumentException("cannot be 0", "x"); + + uint[] x1 = x; + uint[] x2 = Nat160.Create(); + Square(x1, x2); + Multiply(x2, x1, x2); + uint[] x3 = Nat160.Create(); + Square(x2, x3); + Multiply(x3, x1, x3); + uint[] x6 = Nat160.Create(); + SquareN(x3, 3, x6); + Multiply(x6, x3, x6); + uint[] x12 = Nat160.Create(); + SquareN(x6, 6, x12); + Multiply(x12, x6, x12); + uint[] x15 = x12; + SquareN(x12, 3, x15); + Multiply(x15, x3, x15); + uint[] x17 = x15; + SquareN(x15, 2, x17); + Multiply(x17, x2, x17); + uint[] x34 = Nat160.Create(); + SquareN(x17, 17, x34); + Multiply(x34, x17, x34); + uint[] x68 = Nat160.Create(); + SquareN(x34, 34, x68); + Multiply(x68, x34, x68); + uint[] x102 = x68; + SquareN(x68, 34, x102); + Multiply(x102, x34, x102); + uint[] x119 = x34; + SquareN(x102, 17, x119); + Multiply(x119, x17, x119); + uint[] x125 = x102; + SquareN(x119, 6, x125); + Multiply(x125, x6, x125); + uint[] x127 = x6; + SquareN(x125, 2, x127); + Multiply(x127, x2, x127); + + uint[] t = x127; + SquareN(t, 18, t); + Multiply(t, x17, t); + SquareN(t, 2, t); + Multiply(t, x1, t); + SquareN(t, 3, t); + Multiply(t, x2, t); + SquareN(t, 6, t); + Multiply(t, x3, t); + SquareN(t, 4, t); + + // NOTE that x1 and z could be the same array + Multiply(x1, t, z); + } + + public static int IsZero(uint[] x) + { + uint d = 0; + for (int i = 0; i < 5; ++i) + { + d |= x[i]; + } + d = (d >> 1) | (d & 1); + return ((int)d - 1) >> 31; + } + public static void Multiply(uint[] x, uint[] y, uint[] z) { uint[] tt = Nat160.CreateExt(); @@ -91,9 +172,9 @@ namespace Org.BouncyCastle.Math.EC.Custom.Sec public static void Negate(uint[] x, uint[] z) { - if (Nat160.IsZero(x)) + if (0 != IsZero(x)) { - Nat160.Zero(z); + Nat160.Sub(P, P, z); } else { @@ -101,6 +182,26 @@ namespace Org.BouncyCastle.Math.EC.Custom.Sec } } + public static void Random(SecureRandom r, uint[] z) + { + byte[] bb = new byte[5 * 4]; + do + { + r.NextBytes(bb); + Pack.LE_To_UInt32(bb, 0, z, 0, 5); + } + while (0 == Nat.LessThan(5, z, P)); + } + + public static void RandomMult(SecureRandom r, uint[] z) + { + do + { + Random(r, z); + } + while (0 != IsZero(z)); + } + public static void Reduce(uint[] xx, uint[] z) { ulong cc = Nat160.Mul33Add(PInv33, xx, 5, xx, 0, z, 0); |