private DSTU4145ECBinary(Asn1Sequence seq)
{
int index = 0;
if (seq.GetObjectAt(index) is Asn1TaggedObject)
{
Asn1TaggedObject taggedVersion = (Asn1TaggedObject)seq.GetObjectAt(index);
if (taggedVersion.IsExplicit() && 0 == taggedVersion.TagNo)
{
version = DerInteger.GetInstance(taggedVersion.GetObject()).Value;
index++;
}
else
{
throw new ArgumentException("object parse error");
}
}
f = DSTU4145BinaryField.GetInstance(seq.GetObjectAt(index));
index++;
a = DerInteger.GetInstance(seq.GetObjectAt(index));
index++;
b = Asn1OctetString.GetInstance(seq.GetObjectAt(index));
index++;
n = DerInteger.GetInstance(seq.GetObjectAt(index));
index++;
bp = Asn1OctetString.GetInstance(seq.GetObjectAt(index));
}
public DSTU4145ECBinary(ECDomainParameters paramsValue)
{
ECCurve curve = paramsValue.Curve;
if (!ECAlgorithms.IsF2mCurve(curve))
{
throw new ArgumentException("only binary domain is possible");
}
// We always use big-endian in parameter encoding
IPolynomialExtensionField field = (IPolynomialExtensionField)curve.Field;
int[] exponents = field.MinimalPolynomial.GetExponentsPresent();
if (exponents.Length == 3)
{
f = new DSTU4145BinaryField(exponents[2], exponents[1]);
}
else if (exponents.Length == 5)
{
f = new DSTU4145BinaryField(exponents[4], exponents[1], exponents[2], exponents[3]);
}
else
{
throw new ArgumentException("curve must have a trinomial or pentanomial basis");
}
a = new DerInteger(curve.A.ToBigInteger());
b = new DerOctetString(curve.B.GetEncoded());
n = new DerInteger(paramsValue.N);
bp = new DerOctetString(DSTU4145PointEncoder.encodePoint(paramsValue.G));
}