static ECDomainParameters Create(Number a, Number b, Number gX, Number gY, Number order, uint h, IFiniteField ff, Uri uri)
{
ECGroup group = new ECGroup(ff.ToElement(a), ff.ToElement(b), ff.Modulus, ff);
ECPoint basePoint = new ECPoint(group, ff.ToElement(gX), ff.ToElement(gY), ff.ToElement(Number.One));
return(new ECDomainParameters(group, basePoint, order, h, (uint)ff.Modulus.BitCount(), new Classical(order), uri));
}
public ECPoint (ECGroup group, Number x, Number y, Number z)
{
_group = group;
_field = group.FiniteField;
_x = x;
_y = y;
_z = z;
}
public ECPoint(ECGroup group, Number x, Number y, Number z)
{
_group = group;
_field = group.FiniteField;
_x = x;
_y = y;
_z = z;
}
public ECDomainParameters (ECGroup group, ECPoint G, Number order, uint h, uint bits, IFiniteField fieldN, Uri uri)
{
_group = group;
_G = G;
_order = order;
_h = h;
_bits = bits;
_fieldN = fieldN;
_uri = uri;
}
public ECDomainParameters(ECGroup group, ECPoint G, Number order, uint h, uint bits, IFiniteField fieldN, Uri uri)
{
_group = group;
_G = G;
_order = order;
_h = h;
_bits = bits;
_fieldN = fieldN;
_uri = uri;
}
/// <summary>バイト配列より点を作成する (SEC1, 2.3.4)</summary>
public ECPoint(ECGroup group, byte[] data)
{
_group = group;
_field = group.FiniteField;
switch (data[0])
{
case 0: { // 無限遠点
ECPoint tmp = _field.GetInfinityPoint(_group);
_x = tmp._x;
_y = tmp._y;
_z = tmp._z;
return;
}
case 2:
case 3: { // 点圧縮済みデータ
int keyBits = group.P.BitCount();
int keyBytes = (keyBits >> 3) + ((keyBits & 7) == 0 ? 0 : 1);
if (data.Length != keyBytes + 1)
{
throw new ArgumentException();
}
Number x = _field.ToElement(new Number(data, 1, keyBytes, false));
Number y2 = _field.Add(_field.Multiply(_field.Add(_field.Multiply(x, x), _group.A), x), _group.B); // (x^2 + a)*x + b
Number y = _field.Sqrt(y2);
if (_field.ToNormal(y).GetBit(0) != data[0] - 2)
{
y = _field.Modulus - y;
}
_x = x;
_y = y;
_z = _field.ToElement(Number.One);
return;
}
case 4: { // 非圧縮データ
int keyBits = group.P.BitCount();
int keyBytes = (keyBits >> 3) + ((keyBits & 7) == 0 ? 0 : 1);
_x = _field.ToElement(new Number(data, 1, keyBytes, false));
_y = _field.ToElement(new Number(data, 1 + keyBytes, keyBytes, false));
_z = _field.ToElement(Number.One);
return;
}
default:
throw new ArgumentException();
}
}
/// <summary>バイト配列より点を作成する (SEC1, 2.3.4)</summary>
public ECPoint (ECGroup group, byte[] data)
{
_group = group;
_field = group.FiniteField;
switch (data[0]) {
case 0: { // 無限遠点
ECPoint tmp = _field.GetInfinityPoint (_group);
_x = tmp._x;
_y = tmp._y;
_z = tmp._z;
return;
}
case 2:
case 3: { // 点圧縮済みデータ
int keyBits = group.P.BitCount ();
int keyBytes = (keyBits >> 3) + ((keyBits & 7) == 0 ? 0 : 1);
if (data.Length != keyBytes + 1)
throw new ArgumentException ();
Number x = _field.ToElement (new Number (data, 1, keyBytes, false));
Number y2 = _field.Add (_field.Multiply (_field.Add (_field.Multiply (x, x), _group.A), x), _group.B); // (x^2 + a)*x + b
Number y = _field.Sqrt (y2);
if (_field.ToNormal (y).GetBit (0) != data[0] - 2)
y = _field.Modulus - y;
_x = x;
_y = y;
_z = _field.ToElement (Number.One);
return;
}
case 4: { // 非圧縮データ
int keyBits = group.P.BitCount ();
int keyBytes = (keyBits >> 3) + ((keyBits & 7) == 0 ? 0 : 1);
_x = _field.ToElement (new Number (data, 1, keyBytes, false));
_y = _field.ToElement (new Number (data, 1 + keyBytes, keyBytes, false));
_z = _field.ToElement (Number.One);
return;
}
default:
throw new ArgumentException ();
}
}
public override ECPoint GetInfinityPoint (ECGroup group)
{
return new ECPoint (group, PADDED_ZERO, PADDED_ZERO, PADDED_ZERO);
}
public ECDomainParameters (ECGroup group, ECPoint G, Number order, uint h, uint bits, IFiniteField fieldN)
: this (group, G, order, h, bits, fieldN, null)
{
}
public ECDomainParameters(ECGroup group, ECPoint G, Number order, uint h, uint bits, IFiniteField fieldN)
: this(group, G, order, h, bits, fieldN, null)
{
}
void PointCompressTest (int bits, ECGroup group, ECPoint p, int repeats, string name)
{
int bytes = (bits >> 3) + ((bits & 7) == 0 ? 0 : 1) + 1;
for (int i = 0; i < repeats; i ++) {
byte[] tmp = p.ToByteArray (true);
Assert.IsTrue (tmp.Length == bytes, name + " #1");
ECPoint x = new ECPoint (group, tmp).Export ();
ECPoint p2 = p.Export ();
Assert.IsTrue (x.X.CompareTo (p2.X) == 0, name + " #2");
Assert.IsTrue (x.Y.CompareTo (p2.Y) == 0, name + " #3");
p = p.Multiply (Number.CreateRandomElement (group.P));
}
}
public virtual ECPoint GetInfinityPoint (ECGroup group)
{
return new ECPoint (group, Number.Zero, Number.Zero, Number.Zero);
}
public virtual ECPoint ExportECPoint (Number x, Number y, Number z, ECGroup group)
{
if (z.IsOne ())
return new ECPoint (group, x, y, z);
Number iz = Invert (z);
Number z2 = Multiply (iz, iz);
return new ECPoint (group, Multiply (x, z2), Multiply (y, Multiply (z2, iz)), Number.One);
}
public override ECPoint ExportECPoint (Number x, Number y, Number z, ECGroup group)
{
if (montOne == null) montOne = ToElement (Number.One);
if (z.CompareTo (montOne) == 0)
return new ECPoint (group, Multiply (x, Number.One), Multiply (y, Number.One), Number.One);
Number izm = Invert (z);
Number iz = Multiply (izm, Number.One);
Number z2 = Multiply (iz, izm);
return new ECPoint (group, Multiply (x, z2), Multiply (y, (Multiply (z2, izm))), Number.One);
}
