diff options
Diffstat (limited to 'crypto/src/math/ec/custom/sec/SecP192K1Field.cs')
| -rw-r--r-- | crypto/src/math/ec/custom/sec/SecP192K1Field.cs | 111 |
1 files changed, 105 insertions, 6 deletions
diff --git a/crypto/src/math/ec/custom/sec/SecP192K1Field.cs b/crypto/src/math/ec/custom/sec/SecP192K1Field.cs index a00360360..30d53f7dc 100644 --- a/crypto/src/math/ec/custom/sec/SecP192K1Field.cs +++ b/crypto/src/math/ec/custom/sec/SecP192K1Field.cs @@ -1,18 +1,21 @@ 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 { internal class SecP192K1Field { // 2^192 - 2^32 - 2^12 - 2^8 - 2^7 - 2^6 - 2^3 - 1 - internal static readonly uint[] P = new uint[]{ 0xFFFFEE37, 0xFFFFFFFE, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF }; - internal static readonly uint[] PExt = new uint[]{ 0x013C4FD1, 0x00002392, 0x00000001, 0x00000000, 0x00000000, + internal static readonly uint[] P = new uint[]{ 0xFFFFEE37, 0xFFFFFFFE, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, + 0xFFFFFFFF }; + private static readonly uint[] PExt = new uint[]{ 0x013C4FD1, 0x00002392, 0x00000001, 0x00000000, 0x00000000, 0x00000000, 0xFFFFDC6E, 0xFFFFFFFD, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF }; - private static readonly uint[] PExtInv = new uint[]{ 0xFEC3B02F, 0xFFFFDC6D, 0xFFFFFFFE, 0xFFFFFFFF, 0xFFFFFFFF, - 0xFFFFFFFF, 0x00002391, 0x00000002 }; + private static readonly uint[] PExtInv = new uint[]{ 0xFEC3B02F, 0xFFFFDC6D, 0xFFFFFFFE, 0xFFFFFFFF, + 0xFFFFFFFF, 0xFFFFFFFF, 0x00002391, 0x00000002 }; private const uint P5 = 0xFFFFFFFF; private const uint PExt11 = 0xFFFFFFFF; private const uint PInv33 = 0x11C9; @@ -70,6 +73,82 @@ namespace Org.BouncyCastle.Math.EC.Custom.Sec } } + public static void Inv(uint[] x, uint[] z) + { + /* + * Raise this element to the exponent 2^192 - 2^32 - 2^12 - 2^8 - 2^7 - 2^6 - 2^3 - 3 + * + * Breaking up the exponent's binary representation into "repunits", we get: + * { 159 1s } { 1 0s } { 19 1s } { 1 0s } { 3 1s } "000110101" + * + * Therefore we need an addition chain containing 1, 2, 3, 19, 159 (the lengths of the repunits) + * We use: [1], [2], [3], 6, 12, 18, [19], 38, 76, 152, 158, [159] + */ + + if (0 != IsZero(x)) + throw new ArgumentException("cannot be 0", "x"); + + uint[] x1 = x; + uint[] x2 = Nat192.Create(); + Square(x1, x2); + Multiply(x2, x1, x2); + uint[] x3 = Nat192.Create(); + Square(x2, x3); + Multiply(x3, x1, x3); + uint[] x6 = Nat192.Create(); + SquareN(x3, 3, x6); + Multiply(x6, x3, x6); + uint[] x12 = Nat192.Create(); + SquareN(x6, 6, x12); + Multiply(x12, x6, x12); + uint[] x18 = x12; + SquareN(x12, 6, x18); + Multiply(x18, x6, x18); + uint[] x19 = x18; + Square(x18, x19); + Multiply(x19, x1, x19); + uint[] x38 = Nat192.Create(); + SquareN(x19, 19, x38); + Multiply(x38, x19, x38); + uint[] x76 = Nat192.Create(); + SquareN(x38, 38, x76); + Multiply(x76, x38, x76); + uint[] x152 = x38; + SquareN(x76, 76, x152); + Multiply(x152, x76, x152); + uint[] x158 = x76; + SquareN(x152, 6, x158); + Multiply(x158, x6, x158); + uint[] x159 = x6; + Square(x158, x159); + Multiply(x159, x1, x159); + + uint[] t = x159; + SquareN(t, 20, t); + Multiply(t, x19, t); + SquareN(t, 4, t); + Multiply(t, x3, t); + SquareN(t, 5, t); + Multiply(t, x2, t); + SquareN(t, 2, t); + Multiply(t, x1, t); + SquareN(t, 2, 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 < 6; ++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 = Nat192.CreateExt(); @@ -91,9 +170,9 @@ namespace Org.BouncyCastle.Math.EC.Custom.Sec public static void Negate(uint[] x, uint[] z) { - if (Nat192.IsZero(x)) + if (0 != IsZero(x)) { - Nat192.Zero(z); + Nat192.Sub(P, P, z); } else { @@ -101,6 +180,26 @@ namespace Org.BouncyCastle.Math.EC.Custom.Sec } } + public static void Random(SecureRandom r, uint[] z) + { + byte[] bb = new byte[6 * 4]; + do + { + r.NextBytes(bb); + Pack.LE_To_UInt32(bb, 0, z, 0, 6); + } + while (0 == Nat.LessThan(6, 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 = Nat192.Mul33Add(PInv33, xx, 6, xx, 0, z, 0); |