diff options
Diffstat (limited to 'crypto/src/math/ec/custom/sec/SecT113R2Curve.cs')
| -rw-r--r-- | crypto/src/math/ec/custom/sec/SecT113R2Curve.cs | 63 |
1 files changed, 61 insertions, 2 deletions
diff --git a/crypto/src/math/ec/custom/sec/SecT113R2Curve.cs b/crypto/src/math/ec/custom/sec/SecT113R2Curve.cs index abfd26d5b..efe422806 100644 --- a/crypto/src/math/ec/custom/sec/SecT113R2Curve.cs +++ b/crypto/src/math/ec/custom/sec/SecT113R2Curve.cs @@ -1,5 +1,6 @@ using System; +using Org.BouncyCastle.Math.Raw; using Org.BouncyCastle.Utilities.Encoders; namespace Org.BouncyCastle.Math.EC.Custom.Sec @@ -7,7 +8,8 @@ namespace Org.BouncyCastle.Math.EC.Custom.Sec internal class SecT113R2Curve : AbstractF2mCurve { - private const int SecT113R2_DEFAULT_COORDS = COORD_LAMBDA_PROJECTIVE; + private const int SECT113R2_DEFAULT_COORDS = COORD_LAMBDA_PROJECTIVE; + private const int SECT113R2_FE_LONGS = 2; protected readonly SecT113R2Point m_infinity; @@ -21,7 +23,7 @@ namespace Org.BouncyCastle.Math.EC.Custom.Sec this.m_order = new BigInteger(1, Hex.Decode("010000000000000108789B2496AF93")); this.m_cofactor = BigInteger.Two; - this.m_coord = SecT113R2_DEFAULT_COORDS; + this.m_coord = SECT113R2_DEFAULT_COORDS; } protected override ECCurve CloneCurve() @@ -94,5 +96,62 @@ namespace Org.BouncyCastle.Math.EC.Custom.Sec { get { return 0; } } + + public override ECLookupTable CreateCacheSafeLookupTable(ECPoint[] points, int off, int len) + { + ulong[] table = new ulong[len * SECT113R2_FE_LONGS * 2]; + { + int pos = 0; + for (int i = 0; i < len; ++i) + { + ECPoint p = points[off + i]; + Nat128.Copy64(((SecT113FieldElement)p.RawXCoord).x, 0, table, pos); pos += SECT113R2_FE_LONGS; + Nat128.Copy64(((SecT113FieldElement)p.RawYCoord).x, 0, table, pos); pos += SECT113R2_FE_LONGS; + } + } + + return new SecT113R2LookupTable(this, table, len); + } + + private class SecT113R2LookupTable + : ECLookupTable + { + private readonly SecT113R2Curve m_outer; + private readonly ulong[] m_table; + private readonly int m_size; + + internal SecT113R2LookupTable(SecT113R2Curve outer, ulong[] table, int size) + { + this.m_outer = outer; + this.m_table = table; + this.m_size = size; + } + + public virtual int Size + { + get { return m_size; } + } + + public virtual ECPoint Lookup(int index) + { + ulong[] x = Nat128.Create64(), y = Nat128.Create64(); + int pos = 0; + + for (int i = 0; i < m_size; ++i) + { + ulong MASK = (ulong)(long)(((i ^ index) - 1) >> 31); + + for (int j = 0; j < SECT113R2_FE_LONGS; ++j) + { + x[j] ^= m_table[pos + j] & MASK; + y[j] ^= m_table[pos + SECT113R2_FE_LONGS + j] & MASK; + } + + pos += (SECT113R2_FE_LONGS * 2); + } + + return m_outer.CreateRawPoint(new SecT113FieldElement(x), new SecT113FieldElement(y), false); + } + } } } |