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using System;
using System.Diagnostics;
using Org.BouncyCastle.Math.Raw;
using Org.BouncyCastle.Utilities;
using Org.BouncyCastle.Utilities.Encoders;
namespace Org.BouncyCastle.Math.EC.Custom.Sec
{
internal class SecP192K1FieldElement
: AbstractFpFieldElement
{
public static readonly BigInteger Q = new BigInteger(1,
Hex.DecodeStrict("FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEFFFFEE37"));
protected internal readonly uint[] x;
public SecP192K1FieldElement(BigInteger x)
{
if (x == null || x.SignValue < 0 || x.CompareTo(Q) >= 0)
throw new ArgumentException("value invalid for SecP192K1FieldElement", "x");
this.x = SecP192K1Field.FromBigInteger(x);
}
public SecP192K1FieldElement()
{
this.x = Nat192.Create();
}
protected internal SecP192K1FieldElement(uint[] x)
{
this.x = x;
}
public override bool IsZero
{
get { return Nat192.IsZero(x); }
}
public override bool IsOne
{
get { return Nat192.IsOne(x); }
}
public override bool TestBitZero()
{
return Nat192.GetBit(x, 0) == 1;
}
public override BigInteger ToBigInteger()
{
return Nat192.ToBigInteger(x);
}
public override string FieldName
{
get { return "SecP192K1Field"; }
}
public override int FieldSize
{
get { return Q.BitLength; }
}
public override ECFieldElement Add(ECFieldElement b)
{
uint[] z = Nat192.Create();
SecP192K1Field.Add(x, ((SecP192K1FieldElement)b).x, z);
return new SecP192K1FieldElement(z);
}
public override ECFieldElement AddOne()
{
uint[] z = Nat192.Create();
SecP192K1Field.AddOne(x, z);
return new SecP192K1FieldElement(z);
}
public override ECFieldElement Subtract(ECFieldElement b)
{
uint[] z = Nat192.Create();
SecP192K1Field.Subtract(x, ((SecP192K1FieldElement)b).x, z);
return new SecP192K1FieldElement(z);
}
public override ECFieldElement Multiply(ECFieldElement b)
{
uint[] z = Nat192.Create();
SecP192K1Field.Multiply(x, ((SecP192K1FieldElement)b).x, z);
return new SecP192K1FieldElement(z);
}
public override ECFieldElement Divide(ECFieldElement b)
{
//return Multiply(b.Invert());
uint[] z = Nat192.Create();
SecP192K1Field.Inv(((SecP192K1FieldElement)b).x, z);
SecP192K1Field.Multiply(z, x, z);
return new SecP192K1FieldElement(z);
}
public override ECFieldElement Negate()
{
uint[] z = Nat192.Create();
SecP192K1Field.Negate(x, z);
return new SecP192K1FieldElement(z);
}
public override ECFieldElement Square()
{
uint[] z = Nat192.Create();
SecP192K1Field.Square(x, z);
return new SecP192K1FieldElement(z);
}
public override ECFieldElement Invert()
{
//return new SecP192K1FieldElement(ToBigInteger().ModInverse(Q));
uint[] z = Nat192.Create();
SecP192K1Field.Inv(x, z);
return new SecP192K1FieldElement(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()
{
/*
* Raise this element to the exponent 2^190 - 2^30 - 2^10 - 2^6 - 2^5 - 2^4 - 2^1
*
* Breaking up the exponent's binary representation into "repunits", we get:
* { 159 1s } { 1 0s } { 19 1s } { 1 0s } { 3 1s } { 3 0s } { 3 1s } { 1 0s }
*
* Therefore we need an addition chain containing 3, 19, 159 (the lengths of the repunits)
* We use: 1, 2, [3], 6, 8, 16, [19], 35, 70, 140, [159]
*/
uint[] x1 = this.x;
if (Nat192.IsZero(x1) || Nat192.IsOne(x1))
return this;
uint[] x2 = Nat192.Create();
SecP192K1Field.Square(x1, x2);
SecP192K1Field.Multiply(x2, x1, x2);
uint[] x3 = Nat192.Create();
SecP192K1Field.Square(x2, x3);
SecP192K1Field.Multiply(x3, x1, x3);
uint[] x6 = Nat192.Create();
SecP192K1Field.SquareN(x3, 3, x6);
SecP192K1Field.Multiply(x6, x3, x6);
uint[] x8 = x6;
SecP192K1Field.SquareN(x6, 2, x8);
SecP192K1Field.Multiply(x8, x2, x8);
uint[] x16 = x2;
SecP192K1Field.SquareN(x8, 8, x16);
SecP192K1Field.Multiply(x16, x8, x16);
uint[] x19 = x8;
SecP192K1Field.SquareN(x16, 3, x19);
SecP192K1Field.Multiply(x19, x3, x19);
uint[] x35 = Nat192.Create();
SecP192K1Field.SquareN(x19, 16, x35);
SecP192K1Field.Multiply(x35, x16, x35);
uint[] x70 = x16;
SecP192K1Field.SquareN(x35, 35, x70);
SecP192K1Field.Multiply(x70, x35, x70);
uint[] x140 = x35;
SecP192K1Field.SquareN(x70, 70, x140);
SecP192K1Field.Multiply(x140, x70, x140);
uint[] x159 = x70;
SecP192K1Field.SquareN(x140, 19, x159);
SecP192K1Field.Multiply(x159, x19, x159);
uint[] t1 = x159;
SecP192K1Field.SquareN(t1, 20, t1);
SecP192K1Field.Multiply(t1, x19, t1);
SecP192K1Field.SquareN(t1, 4, t1);
SecP192K1Field.Multiply(t1, x3, t1);
SecP192K1Field.SquareN(t1, 6, t1);
SecP192K1Field.Multiply(t1, x3, t1);
SecP192K1Field.Square(t1, t1);
uint[] t2 = x3;
SecP192K1Field.Square(t1, t2);
return Nat192.Eq(x1, t2) ? new SecP192K1FieldElement(t1) : null;
}
public override bool Equals(object obj)
{
return Equals(obj as SecP192K1FieldElement);
}
public override bool Equals(ECFieldElement other)
{
return Equals(other as SecP192K1FieldElement);
}
public virtual bool Equals(SecP192K1FieldElement other)
{
if (this == other)
return true;
if (null == other)
return false;
return Nat192.Eq(x, other.x);
}
public override int GetHashCode()
{
return Q.GetHashCode() ^ Arrays.GetHashCode(x, 0, 6);
}
}
}
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