diff options
Diffstat (limited to 'crypto/src/math/ec/multiplier/MontgomeryLadderMultiplier.cs')
-rw-r--r-- | crypto/src/math/ec/multiplier/MontgomeryLadderMultiplier.cs | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/crypto/src/math/ec/multiplier/MontgomeryLadderMultiplier.cs b/crypto/src/math/ec/multiplier/MontgomeryLadderMultiplier.cs new file mode 100644 index 000000000..e2470a383 --- /dev/null +++ b/crypto/src/math/ec/multiplier/MontgomeryLadderMultiplier.cs @@ -0,0 +1,25 @@ +namespace Org.BouncyCastle.Math.EC.Multiplier +{ + public class MontgomeryLadderMultiplier + : AbstractECMultiplier + { + /** + * Montgomery ladder. + */ + protected override ECPoint MultiplyPositive(ECPoint p, BigInteger k) + { + ECPoint[] R = new ECPoint[]{ p.Curve.Infinity, p }; + + int n = k.BitLength; + int i = n; + while (--i >= 0) + { + int b = k.TestBit(i) ? 1 : 0; + int bp = 1 - b; + R[bp] = R[bp].Add(R[b]); + R[b] = R[b].Twice(); + } + return R[0]; + } + } +} |