diff options
Diffstat (limited to 'core/src/main/java/org/spongycastle/math/ec/custom/sec/SecP224R1Point.java')
| -rw-r--r-- | core/src/main/java/org/spongycastle/math/ec/custom/sec/SecP224R1Point.java | 308 |
1 files changed, 308 insertions, 0 deletions
diff --git a/core/src/main/java/org/spongycastle/math/ec/custom/sec/SecP224R1Point.java b/core/src/main/java/org/spongycastle/math/ec/custom/sec/SecP224R1Point.java new file mode 100644 index 00000000..d44f2f8f --- /dev/null +++ b/core/src/main/java/org/spongycastle/math/ec/custom/sec/SecP224R1Point.java @@ -0,0 +1,308 @@ +package org.spongycastle.math.ec.custom.sec; + +import org.spongycastle.math.ec.ECCurve; +import org.spongycastle.math.ec.ECFieldElement; +import org.spongycastle.math.ec.ECPoint; +import org.spongycastle.math.raw.Nat; +import org.spongycastle.math.raw.Nat224; + +public class SecP224R1Point extends ECPoint.AbstractFp +{ + /** + * Create a point which encodes with point compression. + * + * @param curve + * the curve to use + * @param x + * affine x co-ordinate + * @param y + * affine y co-ordinate + * + * @deprecated Use ECCurve.createPoint to construct points + */ + public SecP224R1Point(ECCurve curve, ECFieldElement x, ECFieldElement y) + { + this(curve, x, y, false); + } + + /** + * Create a point that encodes with or without point compresion. + * + * @param curve + * the curve to use + * @param x + * affine x co-ordinate + * @param y + * affine y co-ordinate + * @param withCompression + * if true encode with point compression + * + * @deprecated per-point compression property will be removed, refer + * {@link #getEncoded(boolean)} + */ + public SecP224R1Point(ECCurve curve, ECFieldElement x, ECFieldElement y, boolean withCompression) + { + super(curve, x, y); + + if ((x == null) != (y == null)) + { + throw new IllegalArgumentException("Exactly one of the field elements is null"); + } + + this.withCompression = withCompression; + } + + SecP224R1Point(ECCurve curve, ECFieldElement x, ECFieldElement y, ECFieldElement[] zs, boolean withCompression) + { + super(curve, x, y, zs); + + this.withCompression = withCompression; + } + + protected ECPoint detach() + { + return new SecP224R1Point(null, getAffineXCoord(), getAffineYCoord()); + } + + public ECPoint add(ECPoint b) + { + if (this.isInfinity()) + { + return b; + } + if (b.isInfinity()) + { + return this; + } + if (this == b) + { + return twice(); + } + + ECCurve curve = this.getCurve(); + + SecP224R1FieldElement X1 = (SecP224R1FieldElement)this.x, Y1 = (SecP224R1FieldElement)this.y; + SecP224R1FieldElement X2 = (SecP224R1FieldElement)b.getXCoord(), Y2 = (SecP224R1FieldElement)b.getYCoord(); + + SecP224R1FieldElement Z1 = (SecP224R1FieldElement)this.zs[0]; + SecP224R1FieldElement Z2 = (SecP224R1FieldElement)b.getZCoord(0); + + int c; + int[] tt1 = Nat224.createExt(); + int[] t2 = Nat224.create(); + int[] t3 = Nat224.create(); + int[] t4 = Nat224.create(); + + boolean Z1IsOne = Z1.isOne(); + int[] U2, S2; + if (Z1IsOne) + { + U2 = X2.x; + S2 = Y2.x; + } + else + { + S2 = t3; + SecP224R1Field.square(Z1.x, S2); + + U2 = t2; + SecP224R1Field.multiply(S2, X2.x, U2); + + SecP224R1Field.multiply(S2, Z1.x, S2); + SecP224R1Field.multiply(S2, Y2.x, S2); + } + + boolean Z2IsOne = Z2.isOne(); + int[] U1, S1; + if (Z2IsOne) + { + U1 = X1.x; + S1 = Y1.x; + } + else + { + S1 = t4; + SecP224R1Field.square(Z2.x, S1); + + U1 = tt1; + SecP224R1Field.multiply(S1, X1.x, U1); + + SecP224R1Field.multiply(S1, Z2.x, S1); + SecP224R1Field.multiply(S1, Y1.x, S1); + } + + int[] H = Nat224.create(); + SecP224R1Field.subtract(U1, U2, H); + + int[] R = t2; + SecP224R1Field.subtract(S1, S2, R); + + // Check if b == this or b == -this + if (Nat224.isZero(H)) + { + if (Nat224.isZero(R)) + { + // this == b, i.e. this must be doubled + return this.twice(); + } + + // this == -b, i.e. the result is the point at infinity + return curve.getInfinity(); + } + + int[] HSquared = t3; + SecP224R1Field.square(H, HSquared); + + int[] G = Nat224.create(); + SecP224R1Field.multiply(HSquared, H, G); + + int[] V = t3; + SecP224R1Field.multiply(HSquared, U1, V); + + SecP224R1Field.negate(G, G); + Nat224.mul(S1, G, tt1); + + c = Nat224.addBothTo(V, V, G); + SecP224R1Field.reduce32(c, G); + + SecP224R1FieldElement X3 = new SecP224R1FieldElement(t4); + SecP224R1Field.square(R, X3.x); + SecP224R1Field.subtract(X3.x, G, X3.x); + + SecP224R1FieldElement Y3 = new SecP224R1FieldElement(G); + SecP224R1Field.subtract(V, X3.x, Y3.x); + SecP224R1Field.multiplyAddToExt(Y3.x, R, tt1); + SecP224R1Field.reduce(tt1, Y3.x); + + SecP224R1FieldElement Z3 = new SecP224R1FieldElement(H); + if (!Z1IsOne) + { + SecP224R1Field.multiply(Z3.x, Z1.x, Z3.x); + } + if (!Z2IsOne) + { + SecP224R1Field.multiply(Z3.x, Z2.x, Z3.x); + } + + ECFieldElement[] zs = new ECFieldElement[]{ Z3 }; + + return new SecP224R1Point(curve, X3, Y3, zs, this.withCompression); + } + + public ECPoint twice() + { + if (this.isInfinity()) + { + return this; + } + + ECCurve curve = this.getCurve(); + + SecP224R1FieldElement Y1 = (SecP224R1FieldElement)this.y; + if (Y1.isZero()) + { + return curve.getInfinity(); + } + + SecP224R1FieldElement X1 = (SecP224R1FieldElement)this.x, Z1 = (SecP224R1FieldElement)this.zs[0]; + + int c; + int[] t1 = Nat224.create(); + int[] t2 = Nat224.create(); + + int[] Y1Squared = Nat224.create(); + SecP224R1Field.square(Y1.x, Y1Squared); + + int[] T = Nat224.create(); + SecP224R1Field.square(Y1Squared, T); + + boolean Z1IsOne = Z1.isOne(); + + int[] Z1Squared = Z1.x; + if (!Z1IsOne) + { + Z1Squared = t2; + SecP224R1Field.square(Z1.x, Z1Squared); + } + + SecP224R1Field.subtract(X1.x, Z1Squared, t1); + + int[] M = t2; + SecP224R1Field.add(X1.x, Z1Squared, M); + SecP224R1Field.multiply(M, t1, M); + c = Nat224.addBothTo(M, M, M); + SecP224R1Field.reduce32(c, M); + + int[] S = Y1Squared; + SecP224R1Field.multiply(Y1Squared, X1.x, S); + c = Nat.shiftUpBits(7, S, 2, 0); + SecP224R1Field.reduce32(c, S); + + c = Nat.shiftUpBits(7, T, 3, 0, t1); + SecP224R1Field.reduce32(c, t1); + + SecP224R1FieldElement X3 = new SecP224R1FieldElement(T); + SecP224R1Field.square(M, X3.x); + SecP224R1Field.subtract(X3.x, S, X3.x); + SecP224R1Field.subtract(X3.x, S, X3.x); + + SecP224R1FieldElement Y3 = new SecP224R1FieldElement(S); + SecP224R1Field.subtract(S, X3.x, Y3.x); + SecP224R1Field.multiply(Y3.x, M, Y3.x); + SecP224R1Field.subtract(Y3.x, t1, Y3.x); + + SecP224R1FieldElement Z3 = new SecP224R1FieldElement(M); + SecP224R1Field.twice(Y1.x, Z3.x); + if (!Z1IsOne) + { + SecP224R1Field.multiply(Z3.x, Z1.x, Z3.x); + } + + return new SecP224R1Point(curve, X3, Y3, new ECFieldElement[]{ Z3 }, this.withCompression); + } + + public ECPoint twicePlus(ECPoint b) + { + if (this == b) + { + return threeTimes(); + } + if (this.isInfinity()) + { + return b; + } + if (b.isInfinity()) + { + return twice(); + } + + ECFieldElement Y1 = this.y; + if (Y1.isZero()) + { + return b; + } + + return twice().add(b); + } + + public ECPoint threeTimes() + { + if (this.isInfinity() || this.y.isZero()) + { + return this; + } + + // NOTE: Be careful about recursions between twicePlus and threeTimes + return twice().add(this); + } + + public ECPoint negate() + { + if (this.isInfinity()) + { + return this; + } + + return new SecP224R1Point(curve, this.x, this.y.negate(), this.zs, this.withCompression); + } +} |