diff options
Diffstat (limited to 'crypto/src/math/ec/custom/sec/SecP192K1FieldElement.cs')
| -rw-r--r-- | crypto/src/math/ec/custom/sec/SecP192K1FieldElement.cs | 214 |
1 files changed, 214 insertions, 0 deletions
diff --git a/crypto/src/math/ec/custom/sec/SecP192K1FieldElement.cs b/crypto/src/math/ec/custom/sec/SecP192K1FieldElement.cs new file mode 100644 index 000000000..2d1f79367 --- /dev/null +++ b/crypto/src/math/ec/custom/sec/SecP192K1FieldElement.cs @@ -0,0 +1,214 @@ +using System; +using System.Diagnostics; + +using Org.BouncyCastle.Utilities; + +namespace Org.BouncyCastle.Math.EC.Custom.Sec +{ + internal class SecP192K1FieldElement + : ECFieldElement + { + public static readonly BigInteger Q = SecP192K1Curve.q; + + protected internal readonly uint[] x; + + public SecP192K1FieldElement(BigInteger x) + { + if (x == null || x.SignValue < 0 || x.CompareTo(Q) >= 0) + throw new ArgumentException("value invalid for SecP192K1FieldElement", "x"); + + this.x = SecP192K1Field.FromBigInteger(x); + } + + public SecP192K1FieldElement() + { + this.x = Nat192.Create(); + } + + protected internal SecP192K1FieldElement(uint[] x) + { + this.x = x; + } + + public override bool IsZero + { + get { return Nat192.IsZero(x); } + } + + public override bool IsOne + { + get { return Nat192.IsOne(x); } + } + + public override bool TestBitZero() + { + return Nat192.GetBit(x, 0) == 1; + } + + public override BigInteger ToBigInteger() + { + return Nat192.ToBigInteger(x); + } + + public override string FieldName + { + get { return "SecP192K1Field"; } + } + + public override int FieldSize + { + get { return Q.BitLength; } + } + + public override ECFieldElement Add(ECFieldElement b) + { + uint[] z = Nat192.Create(); + SecP192K1Field.Add(x, ((SecP192K1FieldElement)b).x, z); + return new SecP192K1FieldElement(z); + } + + public override ECFieldElement AddOne() + { + uint[] z = Nat192.Create(); + SecP192K1Field.AddOne(x, z); + return new SecP192K1FieldElement(z); + } + + public override ECFieldElement Subtract(ECFieldElement b) + { + uint[] z = Nat192.Create(); + SecP192K1Field.Subtract(x, ((SecP192K1FieldElement)b).x, z); + return new SecP192K1FieldElement(z); + } + + public override ECFieldElement Multiply(ECFieldElement b) + { + uint[] z = Nat192.Create(); + SecP192K1Field.Multiply(x, ((SecP192K1FieldElement)b).x, z); + return new SecP192K1FieldElement(z); + } + + public override ECFieldElement Divide(ECFieldElement b) + { + //return Multiply(b.Invert()); + uint[] z = Nat192.Create(); + Mod.Invert(SecP192K1Field.P, ((SecP192K1FieldElement)b).x, z); + SecP192K1Field.Multiply(z, x, z); + return new SecP192K1FieldElement(z); + } + + public override ECFieldElement Negate() + { + uint[] z = Nat192.Create(); + SecP192K1Field.Negate(x, z); + return new SecP192K1FieldElement(z); + } + + public override ECFieldElement Square() + { + uint[] z = Nat192.Create(); + SecP192K1Field.Square(x, z); + return new SecP192K1FieldElement(z); + } + + public override ECFieldElement Invert() + { + //return new SecP192K1FieldElement(ToBigInteger().ModInverse(Q)); + uint[] z = Nat192.Create(); + Mod.Invert(SecP192K1Field.P, x, z); + return new SecP192K1FieldElement(z); + } + + /** + * return a sqrt root - the routine verifies that the calculation returns the right value - if + * none exists it returns null. + */ + public override ECFieldElement Sqrt() + { + /* + * Raise this element to the exponent 2^190 - 2^30 - 2^10 - 2^6 - 2^5 - 2^4 - 2^1 + * + * Breaking up the exponent's binary representation into "repunits", we get: + * { 159 1s } { 1 0s } { 19 1s } { 1 0s } { 3 1s } { 3 0s} { 3 1s } { 1 0s } + * + * Therefore we need an addition chain containing 3, 19, 159 (the lengths of the repunits) + * We use: 1, 2, [3], 6, 8, 16, [19], 35, 70, 140, [159] + */ + + uint[] x1 = this.x; + if (Nat192.IsZero(x1) || Nat192.IsOne(x1)) + { + return this; + } + + uint[] x2 = Nat192.Create(); + SecP192K1Field.Square(x1, x2); + SecP192K1Field.Multiply(x2, x1, x2); + uint[] x3 = Nat192.Create(); + SecP192K1Field.Square(x2, x3); + SecP192K1Field.Multiply(x3, x1, x3); + uint[] x6 = Nat192.Create(); + SecP192K1Field.SquareN(x3, 3, x6); + SecP192K1Field.Multiply(x6, x3, x6); + uint[] x8 = x6; + SecP192K1Field.SquareN(x6, 2, x8); + SecP192K1Field.Multiply(x8, x2, x8); + uint[] x16 = x2; + SecP192K1Field.SquareN(x8, 8, x16); + SecP192K1Field.Multiply(x16, x8, x16); + uint[] x19 = x8; + SecP192K1Field.SquareN(x16, 3, x19); + SecP192K1Field.Multiply(x19, x3, x19); + uint[] x35 = Nat192.Create(); + SecP192K1Field.SquareN(x19, 16, x35); + SecP192K1Field.Multiply(x35, x16, x35); + uint[] x70 = x16; + SecP192K1Field.SquareN(x35, 35, x70); + SecP192K1Field.Multiply(x70, x35, x70); + uint[] x140 = x35; + SecP192K1Field.SquareN(x70, 70, x140); + SecP192K1Field.Multiply(x140, x70, x140); + uint[] x159 = x70; + SecP192K1Field.SquareN(x140, 19, x159); + SecP192K1Field.Multiply(x159, x19, x159); + + uint[] t1 = x159; + SecP192K1Field.SquareN(t1, 20, t1); + SecP192K1Field.Multiply(t1, x19, t1); + SecP192K1Field.SquareN(t1, 4, t1); + SecP192K1Field.Multiply(t1, x3, t1); + SecP192K1Field.SquareN(t1, 6, t1); + SecP192K1Field.Multiply(t1, x3, t1); + SecP192K1Field.Square(t1, t1); + + uint[] t2 = x3; + SecP192K1Field.Square(t1, t2); + + return Arrays.AreEqual(x1, t2) ? new SecP192K1FieldElement(t1) : null; + } + + public override bool Equals(object obj) + { + return Equals(obj as SecP192K1FieldElement); + } + + public override bool Equals(ECFieldElement other) + { + return Equals(other as SecP192K1FieldElement); + } + + public virtual bool Equals(SecP192K1FieldElement other) + { + if (this == other) + return true; + if (null == other) + return false; + return Arrays.AreEqual(x, other.x); + } + + public override int GetHashCode() + { + return Q.GetHashCode() ^ Arrays.GetHashCode(x); + } + } +} |