diff options
Diffstat (limited to 'core/src/main/java/org/bouncycastle/math')
-rw-r--r-- | core/src/main/java/org/bouncycastle/math/ec/ECPoint.java | 59 |
1 files changed, 38 insertions, 21 deletions
diff --git a/core/src/main/java/org/bouncycastle/math/ec/ECPoint.java b/core/src/main/java/org/bouncycastle/math/ec/ECPoint.java index 5cca62ac..caffb071 100644 --- a/core/src/main/java/org/bouncycastle/math/ec/ECPoint.java +++ b/core/src/main/java/org/bouncycastle/math/ec/ECPoint.java @@ -1260,11 +1260,14 @@ public abstract class ECPoint } case ECCurve.COORD_LAMBDA_PROJECTIVE: { + if (X1.isZero()) + { + return b.addSimple(this); + } + ECFieldElement L1 = this.y, Z1 = this.zs[0]; ECFieldElement L2 = b.y, Z2 = b.zs[0]; - // TODO Special case handling for Xi == 0 - boolean Z1IsOne = Z1.bitLength() == 1; ECFieldElement U2 = X2, S2 = L2; if (!Z1IsOne) @@ -1294,23 +1297,39 @@ public abstract class ECPoint return (ECPoint.F2m)curve.getInfinity(); } - B = B.square(); - - ECFieldElement AU1 = A.multiply(U1); - ECFieldElement AU2 = A.multiply(U2); - ECFieldElement ABZ2 = A.multiply(B); - if (!Z2IsOne) + ECFieldElement X3, L3, Z3; + if (X2.isZero()) { - ABZ2 = ABZ2.multiply(Z2); - } + // TODO This can probably be optimized quite a bit - ECFieldElement X3 = AU1.multiply(AU2); - ECFieldElement L3 = AU2.add(B).square().add(ABZ2.multiply(L1.add(Z1))); + ECFieldElement Y1 = getYCoord(), Y2 = L2; + ECFieldElement L = Y1.add(Y2).divide(X1); - ECFieldElement Z3 = ABZ2; - if (!Z1IsOne) + X3 = L.square().add(L).add(X1).add(curve.getA()); + ECFieldElement Y3 = L.multiply(X1.add(X3)).add(X3).add(Y1); + L3 = X3.isZero() ? Y3 : Y3.divide(X3).add(X3); + Z3 = curve.fromBigInteger(ECConstants.ONE); + } + else { - Z3 = Z3.multiply(Z1); + B = B.square(); + + ECFieldElement AU1 = A.multiply(U1); + ECFieldElement AU2 = A.multiply(U2); + ECFieldElement ABZ2 = A.multiply(B); + if (!Z2IsOne) + { + ABZ2 = ABZ2.multiply(Z2); + } + + X3 = AU1.multiply(AU2); + L3 = AU2.add(B).square().add(ABZ2.multiply(L1.add(Z1))); + + Z3 = ABZ2; + if (!Z1IsOne) + { + Z3 = Z3.multiply(Z1); + } } return new ECPoint.F2m(curve, X3, L3, new ECFieldElement[]{ Z3 }, withCompression); @@ -1433,17 +1452,15 @@ public abstract class ECPoint { case ECCurve.COORD_LAMBDA_PROJECTIVE: { - // TODO Special case handling for X2 == 0 - - // NOTE: twicePlus() only optimized for affine argument - ECFieldElement Z2 = b.zs[0]; - if (Z2.bitLength() != 1) + // NOTE: twicePlus() only optimized for lambda-affine argument + ECFieldElement X2 = b.x, Z2 = b.zs[0]; + if (X2.isZero() || Z2.bitLength() != 1) { return twice().add(b); } ECFieldElement L1 = this.y, Z1 = this.zs[0]; - ECFieldElement X2 = b.x, L2 = b.y; + ECFieldElement L2 = b.y; ECFieldElement X1Sq = X1.square(); ECFieldElement L1Sq = L1.square(); |