diff options
Diffstat (limited to 'crypto/src/math/ec/custom/sec/SecT283K1Point.cs')
| -rw-r--r-- | crypto/src/math/ec/custom/sec/SecT283K1Point.cs | 296 |
1 files changed, 296 insertions, 0 deletions
diff --git a/crypto/src/math/ec/custom/sec/SecT283K1Point.cs b/crypto/src/math/ec/custom/sec/SecT283K1Point.cs new file mode 100644 index 000000000..f85706c63 --- /dev/null +++ b/crypto/src/math/ec/custom/sec/SecT283K1Point.cs @@ -0,0 +1,296 @@ +using System; + +namespace Org.BouncyCastle.Math.EC.Custom.Sec +{ + internal class SecT283K1Point + : AbstractF2mPoint + { + /** + * @deprecated Use ECCurve.createPoint to construct points + */ + public SecT283K1Point(ECCurve curve, ECFieldElement x, ECFieldElement y) + : this(curve, x, y, false) + { + } + + /** + * @deprecated per-point compression property will be removed, refer {@link #getEncoded(bool)} + */ + public SecT283K1Point(ECCurve curve, ECFieldElement x, ECFieldElement y, bool withCompression) + : base(curve, x, y, withCompression) + { + if ((x == null) != (y == null)) + throw new ArgumentException("Exactly one of the field elements is null"); + } + + internal SecT283K1Point(ECCurve curve, ECFieldElement x, ECFieldElement y, ECFieldElement[] zs, bool withCompression) + : base(curve, x, y, zs, withCompression) + { + } + + protected override ECPoint Detach() + { + return new SecT283K1Point(null, this.AffineXCoord, this.AffineYCoord); // earlier JDK + } + + public override ECFieldElement YCoord + { + get + { + ECFieldElement X = RawXCoord, L = RawYCoord; + + if (this.IsInfinity || X.IsZero) + return L; + + // Y is actually Lambda (X + Y/X) here; convert to affine value on the fly + ECFieldElement Y = L.Add(X).Multiply(X); + + ECFieldElement Z = RawZCoords[0]; + if (!Z.IsOne) + { + Y = Y.Divide(Z); + } + + return Y; + } + } + + protected internal override bool CompressionYTilde + { + get + { + ECFieldElement X = this.RawXCoord; + if (X.IsZero) + return false; + + ECFieldElement Y = this.RawYCoord; + + // Y is actually Lambda (X + Y/X) here + return Y.TestBitZero() != X.TestBitZero(); + } + } + + public override ECPoint Add(ECPoint b) + { + if (this.IsInfinity) + return b; + if (b.IsInfinity) + return this; + + ECCurve curve = this.Curve; + + ECFieldElement X1 = this.RawXCoord; + ECFieldElement X2 = b.RawXCoord; + + if (X1.IsZero) + { + if (X2.IsZero) + return curve.Infinity; + + return b.Add(this); + } + + ECFieldElement L1 = this.RawYCoord, Z1 = this.RawZCoords[0]; + ECFieldElement L2 = b.RawYCoord, Z2 = b.RawZCoords[0]; + + bool Z1IsOne = Z1.IsOne; + ECFieldElement U2 = X2, S2 = L2; + if (!Z1IsOne) + { + U2 = U2.Multiply(Z1); + S2 = S2.Multiply(Z1); + } + + bool Z2IsOne = Z2.IsOne; + ECFieldElement U1 = X1, S1 = L1; + if (!Z2IsOne) + { + U1 = U1.Multiply(Z2); + S1 = S1.Multiply(Z2); + } + + ECFieldElement A = S1.Add(S2); + ECFieldElement B = U1.Add(U2); + + if (B.IsZero) + { + if (A.IsZero) + return Twice(); + + return curve.Infinity; + } + + ECFieldElement X3, L3, Z3; + if (X2.IsZero) + { + // TODO This can probably be optimized quite a bit + ECPoint p = this.Normalize(); + X1 = p.XCoord; + ECFieldElement Y1 = p.YCoord; + + ECFieldElement Y2 = L2; + ECFieldElement L = Y1.Add(Y2).Divide(X1); + + //X3 = L.Square().Add(L).Add(X1).Add(curve.A); + X3 = L.Square().Add(L).Add(X1); + if (X3.IsZero) + { + //return new SecT283K1Point(curve, X3, curve.B.sqrt(), IsCompressed); + return new SecT283K1Point(curve, X3, curve.B, IsCompressed); + } + + ECFieldElement Y3 = L.Multiply(X1.Add(X3)).Add(X3).Add(Y1); + L3 = Y3.Divide(X3).Add(X3); + Z3 = curve.FromBigInteger(BigInteger.One); + } + else + { + B = B.Square(); + + ECFieldElement AU1 = A.Multiply(U1); + ECFieldElement AU2 = A.Multiply(U2); + + X3 = AU1.Multiply(AU2); + if (X3.IsZero) + { + //return new SecT283K1Point(curve, X3, curve.B.sqrt(), IsCompressed); + return new SecT283K1Point(curve, X3, curve.B, IsCompressed); + } + + ECFieldElement ABZ2 = A.Multiply(B); + if (!Z2IsOne) + { + ABZ2 = ABZ2.Multiply(Z2); + } + + L3 = AU2.Add(B).SquarePlusProduct(ABZ2, L1.Add(Z1)); + + Z3 = ABZ2; + if (!Z1IsOne) + { + Z3 = Z3.Multiply(Z1); + } + } + + return new SecT283K1Point(curve, X3, L3, new ECFieldElement[] { Z3 }, IsCompressed); + } + + public override ECPoint Twice() + { + if (this.IsInfinity) + return this; + + ECCurve curve = this.Curve; + + ECFieldElement X1 = this.RawXCoord; + if (X1.IsZero) + { + // A point with X == 0 is it's own Additive inverse + return curve.Infinity; + } + + ECFieldElement L1 = this.RawYCoord, Z1 = this.RawZCoords[0]; + + bool Z1IsOne = Z1.IsOne; + ECFieldElement Z1Sq = Z1IsOne ? Z1 : Z1.Square(); + ECFieldElement T; + if (Z1IsOne) + { + T = L1.Square().Add(L1); + } + else + { + T = L1.Add(Z1).Multiply(L1); + } + + if (T.IsZero) + { + //return new SecT283K1Point(curve, T, curve.B.sqrt(), withCompression); + return new SecT283K1Point(curve, T, curve.B, IsCompressed); + } + + ECFieldElement X3 = T.Square(); + ECFieldElement Z3 = Z1IsOne ? T : T.Multiply(Z1Sq); + + ECFieldElement t1 = L1.Add(X1).Square(); + ECFieldElement t2 = Z1IsOne ? Z1 : Z1Sq.Square(); + ECFieldElement L3 = t1.Add(T).Add(Z1Sq).Multiply(t1).Add(t2).Add(X3).Add(Z3); + + return new SecT283K1Point(curve, X3, L3, new ECFieldElement[] { Z3 }, IsCompressed); + } + + public override ECPoint TwicePlus(ECPoint b) + { + if (this.IsInfinity) + return b; + if (b.IsInfinity) + return Twice(); + + ECCurve curve = this.Curve; + + ECFieldElement X1 = this.RawXCoord; + if (X1.IsZero) + { + // A point with X == 0 is it's own Additive inverse + return b; + } + + // NOTE: TwicePlus() only optimized for lambda-affine argument + ECFieldElement X2 = b.RawXCoord, Z2 = b.RawZCoords[0]; + if (X2.IsZero || !Z2.IsOne) + { + return Twice().Add(b); + } + + ECFieldElement L1 = this.RawYCoord, Z1 = this.RawZCoords[0]; + ECFieldElement L2 = b.RawYCoord; + + ECFieldElement X1Sq = X1.Square(); + ECFieldElement L1Sq = L1.Square(); + ECFieldElement Z1Sq = Z1.Square(); + ECFieldElement L1Z1 = L1.Multiply(Z1); + + //ECFieldElement T = curve.A.Multiply(Z1Sq).Add(L1Sq).Add(L1Z1); + ECFieldElement T = L1Sq.Add(L1Z1); + ECFieldElement L2plus1 = L2.AddOne(); + //ECFieldElement A = curve.A.Add(L2plus1).Multiply(Z1Sq).Add(L1Sq).MultiplyPlusProduct(T, X1Sq, Z1Sq); + ECFieldElement A = L2plus1.Multiply(Z1Sq).Add(L1Sq).MultiplyPlusProduct(T, X1Sq, Z1Sq); + ECFieldElement X2Z1Sq = X2.Multiply(Z1Sq); + ECFieldElement B = X2Z1Sq.Add(T).Square(); + + if (B.IsZero) + { + if (A.IsZero) + return b.Twice(); + + return curve.Infinity; + } + + if (A.IsZero) + { + //return new SecT283K1Point(curve, A, curve.B.sqrt(), withCompression); + return new SecT283K1Point(curve, A, curve.B, IsCompressed); + } + + ECFieldElement X3 = A.Square().Multiply(X2Z1Sq); + ECFieldElement Z3 = A.Multiply(B).Multiply(Z1Sq); + ECFieldElement L3 = A.Add(B).Square().MultiplyPlusProduct(T, L2plus1, Z3); + + return new SecT283K1Point(curve, X3, L3, new ECFieldElement[] { Z3 }, IsCompressed); + } + + public override ECPoint Negate() + { + if (this.IsInfinity) + return this; + + ECFieldElement X = this.RawXCoord; + if (X.IsZero) + return this; + + // L is actually Lambda (X + Y/X) here + ECFieldElement L = this.RawYCoord, Z = this.RawZCoords[0]; + return new SecT283K1Point(Curve, X, L.Add(Z), new ECFieldElement[] { Z }, IsCompressed); + } + } +} |