diff options
Diffstat (limited to 'core/src/main/java/org/bouncycastle/math/ec/ECPoint.java')
| -rw-r--r-- | core/src/main/java/org/bouncycastle/math/ec/ECPoint.java | 24 |
1 files changed, 21 insertions, 3 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 9cd51b6e..6b4ceae9 100644 --- a/core/src/main/java/org/bouncycastle/math/ec/ECPoint.java +++ b/core/src/main/java/org/bouncycastle/math/ec/ECPoint.java @@ -1562,9 +1562,27 @@ public abstract class ECPoint if (b.bitLength() < (curve.getFieldSize() >> 1)) { ECFieldElement t1 = L1.add(X1).square(); - ECFieldElement t2 = aZ1Sq.square(); - ECFieldElement t3 = curve.getB().multiply(Z1Sq.square()); - L3 = t1.add(T).add(Z1Sq).multiply(t1).add(t2.add(t3)).add(X3).add(a.addOne().multiply(Z3)); + ECFieldElement t4; + if (b.isOne()) + { + t4 = aZ1Sq.add(Z1Sq).square(); + } + else + { + // TODO t2/t3 can be calculated with one square if we pre-compute sqrt(b) + ECFieldElement t2 = aZ1Sq.square(); + ECFieldElement t3 = b.multiply(Z1Sq.square()); + t4 = t2.add(t3); + } + L3 = t1.add(T).add(Z1Sq).multiply(t1).add(t4).add(X3); + if (a.isZero()) + { + L3 = L3.add(Z3); + } + else if (!a.isOne()) + { + L3 = L3.add(a.addOne().multiply(Z3)); + } } else { |