diff options
Diffstat (limited to 'crypto/src/math/ec/custom/sec/SecP192R1Field.cs')
| -rw-r--r-- | crypto/src/math/ec/custom/sec/SecP192R1Field.cs | 102 |
1 files changed, 96 insertions, 6 deletions
diff --git a/crypto/src/math/ec/custom/sec/SecP192R1Field.cs b/crypto/src/math/ec/custom/sec/SecP192R1Field.cs index 096c2b51f..2061d1359 100644 --- a/crypto/src/math/ec/custom/sec/SecP192R1Field.cs +++ b/crypto/src/math/ec/custom/sec/SecP192R1Field.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 SecP192R1Field { // 2^192 - 2^64 - 1 - internal static readonly uint[] P = new uint[]{ 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFE, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF }; - internal static readonly uint[] PExt = new uint[]{ 0x00000001, 0x00000000, 0x00000002, 0x00000000, 0x00000001, + internal static readonly uint[] P = new uint[]{ 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFE, 0xFFFFFFFF, 0xFFFFFFFF, + 0xFFFFFFFF }; + private static readonly uint[] PExt = new uint[]{ 0x00000001, 0x00000000, 0x00000002, 0x00000000, 0x00000001, 0x00000000, 0xFFFFFFFE, 0xFFFFFFFF, 0xFFFFFFFD, 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFF }; - private static readonly uint[] PExtInv = new uint[]{ 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFD, 0xFFFFFFFF, 0xFFFFFFFE, - 0xFFFFFFFF, 0x00000001, 0x00000000, 0x00000002 }; + private static readonly uint[] PExtInv = new uint[]{ 0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFD, 0xFFFFFFFF, + 0xFFFFFFFE, 0xFFFFFFFF, 0x00000001, 0x00000000, 0x00000002 }; private const uint P5 = 0xFFFFFFFF; private const uint PExt11 = 0xFFFFFFFF; @@ -69,6 +72,73 @@ namespace Org.BouncyCastle.Math.EC.Custom.Sec } } + public static void Inv(uint[] x, uint[] z) + { + /* + * Raise this element to the exponent 2^192 - 2^64 - 1 + * + * Breaking up the exponent's binary representation into "repunits", we get: + * { 127 1s } { 1 0s } { 62 1s } { 1 0s } { 1 1s } + * + * Therefore we need an addition chain containing 1, 62, 127 (the lengths of the repunits) + * We use: [1], 2, 3, 6, 12, 24, 30, 32, [62], 65, [127] + */ + + 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[] x24 = Nat192.Create(); + SquareN(x12, 12, x24); + Multiply(x24, x12, x24); + uint[] x30 = x12; + SquareN(x24, 6, x30); + Multiply(x30, x6, x30); + uint[] x32 = x6; + SquareN(x30, 2, x32); + Multiply(x32, x2, x32); + uint[] x62 = x2; + SquareN(x32, 30, x62); + Multiply(x62, x30, x62); + uint[] x65 = x24; + SquareN(x62, 3, x65); + Multiply(x65, x3, x65); + uint[] x127 = x3; + SquareN(x65, 62, x127); + Multiply(x127, x62, x127); + + uint[] t = x127; + SquareN(t, 63, t); + Multiply(t, x62, 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(); @@ -90,9 +160,9 @@ 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 { @@ -100,6 +170,26 @@ 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 xx06 = xx[6], xx07 = xx[7], xx08 = xx[8]; |