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using System;
using Org.BouncyCastle.Math.EC.Multiplier;
using Org.BouncyCastle.Math.Raw;
using Org.BouncyCastle.Utilities.Encoders;
namespace Org.BouncyCastle.Math.EC.Custom.Sec
{
internal class SecT409K1Curve
: AbstractF2mCurve
{
private const int SECT409K1_DEFAULT_COORDS = COORD_LAMBDA_PROJECTIVE;
private const int SECT409K1_FE_LONGS = 7;
protected readonly SecT409K1Point m_infinity;
public SecT409K1Curve()
: base(409, 87, 0, 0)
{
this.m_infinity = new SecT409K1Point(this, null, null);
this.m_a = FromBigInteger(BigInteger.Zero);
this.m_b = FromBigInteger(BigInteger.One);
this.m_order = new BigInteger(1, Hex.Decode("7FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFE5F83B2D4EA20400EC4557D5ED3E3E7CA5B4B5C83B8E01E5FCF"));
this.m_cofactor = BigInteger.ValueOf(4);
this.m_coord = SECT409K1_DEFAULT_COORDS;
}
protected override ECCurve CloneCurve()
{
return new SecT409K1Curve();
}
public override bool SupportsCoordinateSystem(int coord)
{
switch (coord)
{
case COORD_LAMBDA_PROJECTIVE:
return true;
default:
return false;
}
}
protected override ECMultiplier CreateDefaultMultiplier()
{
return new WTauNafMultiplier();
}
public override ECPoint Infinity
{
get { return m_infinity; }
}
public override int FieldSize
{
get { return 409; }
}
public override ECFieldElement FromBigInteger(BigInteger x)
{
return new SecT409FieldElement(x);
}
protected internal override ECPoint CreateRawPoint(ECFieldElement x, ECFieldElement y, bool withCompression)
{
return new SecT409K1Point(this, x, y, withCompression);
}
protected internal override ECPoint CreateRawPoint(ECFieldElement x, ECFieldElement y, ECFieldElement[] zs, bool withCompression)
{
return new SecT409K1Point(this, x, y, zs, withCompression);
}
public override bool IsKoblitz
{
get { return true; }
}
public virtual int M
{
get { return 409; }
}
public virtual bool IsTrinomial
{
get { return true; }
}
public virtual int K1
{
get { return 87; }
}
public virtual int K2
{
get { return 0; }
}
public virtual int K3
{
get { return 0; }
}
public override ECLookupTable CreateCacheSafeLookupTable(ECPoint[] points, int off, int len)
{
ulong[] table = new ulong[len * SECT409K1_FE_LONGS * 2];
{
int pos = 0;
for (int i = 0; i < len; ++i)
{
ECPoint p = points[off + i];
Nat448.Copy64(((SecT409FieldElement)p.RawXCoord).x, 0, table, pos); pos += SECT409K1_FE_LONGS;
Nat448.Copy64(((SecT409FieldElement)p.RawYCoord).x, 0, table, pos); pos += SECT409K1_FE_LONGS;
}
}
return new SecT409K1LookupTable(this, table, len);
}
private class SecT409K1LookupTable
: ECLookupTable
{
private readonly SecT409K1Curve m_outer;
private readonly ulong[] m_table;
private readonly int m_size;
internal SecT409K1LookupTable(SecT409K1Curve 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 = Nat448.Create64(), y = Nat448.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 < SECT409K1_FE_LONGS; ++j)
{
x[j] ^= m_table[pos + j] & MASK;
y[j] ^= m_table[pos + SECT409K1_FE_LONGS + j] & MASK;
}
pos += (SECT409K1_FE_LONGS * 2);
}
return m_outer.CreateRawPoint(new SecT409FieldElement(x), new SecT409FieldElement(y), false);
}
}
}
}
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