diff options
| -rw-r--r-- | crypto/src/math/ec/abc/Tnaf.cs | 17 | ||||
| -rw-r--r-- | crypto/src/math/ec/multiplier/WTauNafMultiplier.cs | 3 |
2 files changed, 16 insertions, 4 deletions
diff --git a/crypto/src/math/ec/abc/Tnaf.cs b/crypto/src/math/ec/abc/Tnaf.cs index cd3e90f46..944f0e229 100644 --- a/crypto/src/math/ec/abc/Tnaf.cs +++ b/crypto/src/math/ec/abc/Tnaf.cs @@ -722,7 +722,7 @@ namespace Org.BouncyCastle.Math.EC.Abc int i = 0; // while lambda <> (0, 0) - while (!(r0.Equals(BigInteger.Zero) && r1.Equals(BigInteger.Zero))) + while ((r0.SignValue | r1.SignValue) != 0) { // if r0 is odd if (r0.TestBit(0)) @@ -802,7 +802,20 @@ namespace Org.BouncyCastle.Math.EC.Abc if (existing is PartModPreCompInfo) return existing; - var lucas = GetLucas(m_mu, m_curve.FieldSize, m_doV)[1]; + BigInteger lucas; + if (m_curve.IsKoblitz) + { + /* + * Jerome A. Solinas, "Improved Algorithms for Arithmetic on Anomalous Binary Curves", (21). + */ + lucas = BigInteger.One.ShiftLeft(m_curve.FieldSize).Add(BigInteger.One).Subtract( + m_curve.Order.Multiply(m_curve.Cofactor)); + } + else + { + lucas = GetLucas(m_mu, m_curve.FieldSize, m_doV)[1]; + } + var si = GetSi(m_curve); return new PartModPreCompInfo(lucas, si[0], si[1]); diff --git a/crypto/src/math/ec/multiplier/WTauNafMultiplier.cs b/crypto/src/math/ec/multiplier/WTauNafMultiplier.cs index d986e7f01..6631657f4 100644 --- a/crypto/src/math/ec/multiplier/WTauNafMultiplier.cs +++ b/crypto/src/math/ec/multiplier/WTauNafMultiplier.cs @@ -24,8 +24,7 @@ namespace Org.BouncyCastle.Math.EC.Multiplier */ protected override ECPoint MultiplyPositive(ECPoint point, BigInteger k) { - AbstractF2mPoint p = point as AbstractF2mPoint; - if (p == null) + if (!(point is AbstractF2mPoint p)) throw new ArgumentException("Only AbstractF2mPoint can be used in WTauNafMultiplier"); AbstractF2mCurve curve = (AbstractF2mCurve)p.Curve; |