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using System;
using Org.BouncyCastle.Math.Raw;
using Org.BouncyCastle.Utilities;
using Org.BouncyCastle.Utilities.Encoders;
namespace Org.BouncyCastle.Math.EC.Custom.Sec
{
internal class SecP224R1FieldElement
: AbstractFpFieldElement
{
public static readonly BigInteger Q = new BigInteger(1,
Hex.DecodeStrict("FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF000000000000000000000001"));
protected internal readonly uint[] x;
public SecP224R1FieldElement(BigInteger x)
{
if (x == null || x.SignValue < 0 || x.CompareTo(Q) >= 0)
throw new ArgumentException("value invalid for SecP224R1FieldElement", "x");
this.x = SecP224R1Field.FromBigInteger(x);
}
public SecP224R1FieldElement()
{
this.x = Nat224.Create();
}
protected internal SecP224R1FieldElement(uint[] x)
{
this.x = x;
}
public override bool IsZero
{
get { return Nat224.IsZero(x); }
}
public override bool IsOne
{
get { return Nat224.IsOne(x); }
}
public override bool TestBitZero()
{
return Nat224.GetBit(x, 0) == 1;
}
public override BigInteger ToBigInteger()
{
return Nat224.ToBigInteger(x);
}
public override string FieldName
{
get { return "SecP224R1Field"; }
}
public override int FieldSize
{
get { return Q.BitLength; }
}
public override ECFieldElement Add(ECFieldElement b)
{
uint[] z = Nat224.Create();
SecP224R1Field.Add(x, ((SecP224R1FieldElement)b).x, z);
return new SecP224R1FieldElement(z);
}
public override ECFieldElement AddOne()
{
uint[] z = Nat224.Create();
SecP224R1Field.AddOne(x, z);
return new SecP224R1FieldElement(z);
}
public override ECFieldElement Subtract(ECFieldElement b)
{
uint[] z = Nat224.Create();
SecP224R1Field.Subtract(x, ((SecP224R1FieldElement)b).x, z);
return new SecP224R1FieldElement(z);
}
public override ECFieldElement Multiply(ECFieldElement b)
{
uint[] z = Nat224.Create();
SecP224R1Field.Multiply(x, ((SecP224R1FieldElement)b).x, z);
return new SecP224R1FieldElement(z);
}
public override ECFieldElement Divide(ECFieldElement b)
{
//return Multiply(b.Invert());
uint[] z = Nat224.Create();
SecP224R1Field.Inv(((SecP224R1FieldElement)b).x, z);
SecP224R1Field.Multiply(z, x, z);
return new SecP224R1FieldElement(z);
}
public override ECFieldElement Negate()
{
uint[] z = Nat224.Create();
SecP224R1Field.Negate(x, z);
return new SecP224R1FieldElement(z);
}
public override ECFieldElement Square()
{
uint[] z = Nat224.Create();
SecP224R1Field.Square(x, z);
return new SecP224R1FieldElement(z);
}
public override ECFieldElement Invert()
{
//return new SecP224R1FieldElement(ToBigInteger().ModInverse(Q));
uint[] z = Nat224.Create();
SecP224R1Field.Inv(x, z);
return new SecP224R1FieldElement(z);
}
/**
* return a sqrt root - the routine verifies that the calculation returns the right value - if
* none exists it returns null.
*/
public override ECFieldElement Sqrt()
{
uint[] c = this.x;
if (Nat224.IsZero(c) || Nat224.IsOne(c))
return this;
uint[] nc = Nat224.Create();
SecP224R1Field.Negate(c, nc);
uint[] r = Mod.Random(SecP224R1Field.P);
uint[] t = Nat224.Create();
if (!IsSquare(c))
return null;
while (!TrySqrt(nc, r, t))
{
SecP224R1Field.AddOne(r, r);
}
SecP224R1Field.Square(t, r);
return Nat224.Eq(c, r) ? new SecP224R1FieldElement(t) : null;
}
public override bool Equals(object obj)
{
return Equals(obj as SecP224R1FieldElement);
}
public override bool Equals(ECFieldElement other)
{
return Equals(other as SecP224R1FieldElement);
}
public virtual bool Equals(SecP224R1FieldElement other)
{
if (this == other)
return true;
if (null == other)
return false;
return Nat224.Eq(x, other.x);
}
public override int GetHashCode()
{
return Q.GetHashCode() ^ Arrays.GetHashCode(x, 0, 7);
}
private static bool IsSquare(uint[] x)
{
uint[] t1 = Nat224.Create();
uint[] t2 = Nat224.Create();
Nat224.Copy(x, t1);
for (int i = 0; i < 7; ++i)
{
Nat224.Copy(t1, t2);
SecP224R1Field.SquareN(t1, 1 << i, t1);
SecP224R1Field.Multiply(t1, t2, t1);
}
SecP224R1Field.SquareN(t1, 95, t1);
return Nat224.IsOne(t1);
}
private static void RM(uint[] nc, uint[] d0, uint[] e0, uint[] d1, uint[] e1, uint[] f1, uint[] t)
{
SecP224R1Field.Multiply(e1, e0, t);
SecP224R1Field.Multiply(t, nc, t);
SecP224R1Field.Multiply(d1, d0, f1);
SecP224R1Field.Add(f1, t, f1);
SecP224R1Field.Multiply(d1, e0, t);
Nat224.Copy(f1, d1);
SecP224R1Field.Multiply(e1, d0, e1);
SecP224R1Field.Add(e1, t, e1);
SecP224R1Field.Square(e1, f1);
SecP224R1Field.Multiply(f1, nc, f1);
}
private static void RP(uint[] nc, uint[] d1, uint[] e1, uint[] f1, uint[] t)
{
Nat224.Copy(nc, f1);
uint[] d0 = Nat224.Create();
uint[] e0 = Nat224.Create();
for (int i = 0; i < 7; ++i)
{
Nat224.Copy(d1, d0);
Nat224.Copy(e1, e0);
int j = 1 << i;
while (--j >= 0)
{
RS(d1, e1, f1, t);
}
RM(nc, d0, e0, d1, e1, f1, t);
}
}
private static void RS(uint[] d, uint[] e, uint[] f, uint[] t)
{
SecP224R1Field.Multiply(e, d, e);
SecP224R1Field.Twice(e, e);
SecP224R1Field.Square(d, t);
SecP224R1Field.Add(f, t, d);
SecP224R1Field.Multiply(f, t, f);
uint c = Nat.ShiftUpBits(7, f, 2, 0);
SecP224R1Field.Reduce32(c, f);
}
private static bool TrySqrt(uint[] nc, uint[] r, uint[] t)
{
uint[] d1 = Nat224.Create();
Nat224.Copy(r, d1);
uint[] e1 = Nat224.Create();
e1[0] = 1;
uint[] f1 = Nat224.Create();
RP(nc, d1, e1, f1, t);
uint[] d0 = Nat224.Create();
uint[] e0 = Nat224.Create();
for (int k = 1; k < 96; ++k)
{
Nat224.Copy(d1, d0);
Nat224.Copy(e1, e0);
RS(d1, e1, f1, t);
if (Nat224.IsZero(d1))
{
SecP224R1Field.Inv(e0, t);
SecP224R1Field.Multiply(t, d0, t);
return true;
}
}
return false;
}
}
}
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