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| author | Peter Dettman <peter.dettman@bouncycastle.org> | 2014-04-11 10:11:27 +0700 |
|---|---|---|
| committer | Peter Dettman <peter.dettman@bouncycastle.org> | 2014-04-11 10:11:27 +0700 |
| commit | 10a2318ac5f90a581a919e9d4de489c6d217f5a7 (patch) | |
| tree | 4de4091d3bf2bab7097a509e55dd7310b1dbebc3 /crypto/src/math | |
| parent | Update version to beta.4 following beta.3 release (diff) | |
| download | BouncyCastle.NET-ed25519-10a2318ac5f90a581a919e9d4de489c6d217f5a7.tar.xz | |
Check for low-weight numbers in DH parameter generation and RSA key generation
Diffstat (limited to 'crypto/src/math')
| -rw-r--r-- | crypto/src/math/ec/multiplier/WNafUtilities.cs | 11 |
1 files changed, 11 insertions, 0 deletions
diff --git a/crypto/src/math/ec/multiplier/WNafUtilities.cs b/crypto/src/math/ec/multiplier/WNafUtilities.cs index 98e4f545f..865b9073e 100644 --- a/crypto/src/math/ec/multiplier/WNafUtilities.cs +++ b/crypto/src/math/ec/multiplier/WNafUtilities.cs @@ -268,6 +268,17 @@ namespace Org.BouncyCastle.Math.EC.Multiplier return wnaf; } + public static int GetNafWeight(BigInteger k) + { + if (k.SignValue == 0) + return 0; + + BigInteger _3k = k.ShiftLeft(1).Add(k); + BigInteger diff = _3k.Xor(k); + + return diff.BitCount; + } + public static WNafPreCompInfo GetWNafPreCompInfo(ECPoint p) { return GetWNafPreCompInfo(p.Curve.GetPreCompInfo(p, PRECOMP_NAME)); |