diff options
Diffstat (limited to 'crypto/src/math/ec/custom/sec/SecP160R2FieldElement.cs')
| -rw-r--r-- | crypto/src/math/ec/custom/sec/SecP160R2FieldElement.cs | 218 |
1 files changed, 218 insertions, 0 deletions
diff --git a/crypto/src/math/ec/custom/sec/SecP160R2FieldElement.cs b/crypto/src/math/ec/custom/sec/SecP160R2FieldElement.cs new file mode 100644 index 000000000..bdb5245b2 --- /dev/null +++ b/crypto/src/math/ec/custom/sec/SecP160R2FieldElement.cs @@ -0,0 +1,218 @@ +using System; + +using Org.BouncyCastle.Math.Raw; +using Org.BouncyCastle.Utilities; + +namespace Org.BouncyCastle.Math.EC.Custom.Sec +{ + internal class SecP160R2FieldElement + : ECFieldElement + { + public static readonly BigInteger Q = SecP160R2Curve.q; + + protected internal readonly uint[] x; + + public SecP160R2FieldElement(BigInteger x) + { + if (x == null || x.SignValue < 0 || x.CompareTo(Q) >= 0) + throw new ArgumentException("value invalid for SecP160R2FieldElement", "x"); + + this.x = SecP160R2Field.FromBigInteger(x); + } + + public SecP160R2FieldElement() + { + this.x = Nat160.Create(); + } + + protected internal SecP160R2FieldElement(uint[] x) + { + this.x = x; + } + + public override bool IsZero + { + get { return Nat160.IsZero(x); } + } + + public override bool IsOne + { + get { return Nat160.IsOne(x); } + } + + public override bool TestBitZero() + { + return Nat160.GetBit(x, 0) == 1; + } + + public override BigInteger ToBigInteger() + { + return Nat160.ToBigInteger(x); + } + + public override string FieldName + { + get { return "SecP160R2Field"; } + } + + public override int FieldSize + { + get { return Q.BitLength; } + } + + public override ECFieldElement Add(ECFieldElement b) + { + uint[] z = Nat160.Create(); + SecP160R2Field.Add(x, ((SecP160R2FieldElement)b).x, z); + return new SecP160R2FieldElement(z); + } + + public override ECFieldElement AddOne() + { + uint[] z = Nat160.Create(); + SecP160R2Field.AddOne(x, z); + return new SecP160R2FieldElement(z); + } + + public override ECFieldElement Subtract(ECFieldElement b) + { + uint[] z = Nat160.Create(); + SecP160R2Field.Subtract(x, ((SecP160R2FieldElement)b).x, z); + return new SecP160R2FieldElement(z); + } + + public override ECFieldElement Multiply(ECFieldElement b) + { + uint[] z = Nat160.Create(); + SecP160R2Field.Multiply(x, ((SecP160R2FieldElement)b).x, z); + return new SecP160R2FieldElement(z); + } + + public override ECFieldElement Divide(ECFieldElement b) + { + // return Multiply(b.invert()); + uint[] z = Nat160.Create(); + Mod.Invert(SecP160R2Field.P, ((SecP160R2FieldElement)b).x, z); + SecP160R2Field.Multiply(z, x, z); + return new SecP160R2FieldElement(z); + } + + public override ECFieldElement Negate() + { + uint[] z = Nat160.Create(); + SecP160R2Field.Negate(x, z); + return new SecP160R2FieldElement(z); + } + + public override ECFieldElement Square() + { + uint[] z = Nat160.Create(); + SecP160R2Field.Square(x, z); + return new SecP160R2FieldElement(z); + } + + public override ECFieldElement Invert() + { + // return new SecP160R2FieldElement(ToBigInteger().modInverse(Q)); + uint[] z = Nat160.Create(); + Mod.Invert(SecP160R2Field.P, x, z); + return new SecP160R2FieldElement(z); + } + + // D.1.4 91 + /** + * 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 2^158 - 2^30 - 2^12 - 2^10 - 2^7 - 2^6 - 2^5 - 2^1 - 2^0 + * + * Breaking up the exponent's binary representation into "repunits", we get: { 127 1s } { 1 + * 0s } { 17 1s } { 1 0s } { 1 1s } { 1 0s } { 2 1s } { 3 0s } { 3 1s } { 1 0s } { 1 1s } + * + * Therefore we need an Addition chain containing 1, 2, 3, 17, 127 (the lengths of the repunits) + * We use: [1], [2], [3], 4, 7, 14, [17], 31, 62, 124, [127] + */ + + uint[] x1 = this.x; + if (Nat160.IsZero(x1) || Nat160.IsOne(x1)) + { + return this; + } + + uint[] x2 = Nat160.Create(); + SecP160R2Field.Square(x1, x2); + SecP160R2Field.Multiply(x2, x1, x2); + uint[] x3 = Nat160.Create(); + SecP160R2Field.Square(x2, x3); + SecP160R2Field.Multiply(x3, x1, x3); + uint[] x4 = Nat160.Create(); + SecP160R2Field.Square(x3, x4); + SecP160R2Field.Multiply(x4, x1, x4); + uint[] x7 = Nat160.Create(); + SecP160R2Field.SquareN(x4, 3, x7); + SecP160R2Field.Multiply(x7, x3, x7); + uint[] x14 = x4; + SecP160R2Field.SquareN(x7, 7, x14); + SecP160R2Field.Multiply(x14, x7, x14); + uint[] x17 = x7; + SecP160R2Field.SquareN(x14, 3, x17); + SecP160R2Field.Multiply(x17, x3, x17); + uint[] x31 = Nat160.Create(); + SecP160R2Field.SquareN(x17, 14, x31); + SecP160R2Field.Multiply(x31, x14, x31); + uint[] x62 = x14; + SecP160R2Field.SquareN(x31, 31, x62); + SecP160R2Field.Multiply(x62, x31, x62); + uint[] x124 = x31; + SecP160R2Field.SquareN(x62, 62, x124); + SecP160R2Field.Multiply(x124, x62, x124); + uint[] x127 = x62; + SecP160R2Field.SquareN(x124, 3, x127); + SecP160R2Field.Multiply(x127, x3, x127); + + uint[] t1 = x127; + SecP160R2Field.SquareN(t1, 18, t1); + SecP160R2Field.Multiply(t1, x17, t1); + SecP160R2Field.SquareN(t1, 2, t1); + SecP160R2Field.Multiply(t1, x1, t1); + SecP160R2Field.SquareN(t1, 3, t1); + SecP160R2Field.Multiply(t1, x2, t1); + SecP160R2Field.SquareN(t1, 6, t1); + SecP160R2Field.Multiply(t1, x3, t1); + SecP160R2Field.SquareN(t1, 2, t1); + SecP160R2Field.Multiply(t1, x1, t1); + + uint[] t2 = x2; + SecP160R2Field.Square(t1, t2); + + return Nat160.Eq(x1, t2) ? new SecP160R2FieldElement(t1) : null; + } + + public override bool Equals(object obj) + { + return Equals(obj as SecP160R2FieldElement); + } + + public override bool Equals(ECFieldElement other) + { + return Equals(other as SecP160R2FieldElement); + } + + public virtual bool Equals(SecP160R2FieldElement other) + { + if (this == other) + return true; + if (null == other) + return false; + return Nat160.Eq(x, other.x); + } + + public override int GetHashCode() + { + return Q.GetHashCode() ^ Arrays.GetHashCode(x, 0, 5); + } + } +} |