// encoding and decoding
SecureVector<byte> EC2OSP(const PointGFp& point, byte format)
{
if(point.is_zero())
return SecureVector<byte>(1); // single 0 byte
const size_t p_bytes = point.get_curve().get_p().bytes();
BigInt x = point.get_affine_x();
BigInt y = point.get_affine_y();
SecureVector<byte> bX = BigInt::encode_1363(x, p_bytes);
SecureVector<byte> bY = BigInt::encode_1363(y, p_bytes);
if(format == PointGFp::UNCOMPRESSED)
{
SecureVector<byte> result;
result.push_back(0x04);
result += bX;
result += bY;
return result;
}
else if(format == PointGFp::COMPRESSED)
{
SecureVector<byte> result;
result.push_back(0x02 | static_cast<byte>(y.get_bit(0)));
result += bX;
return result;
}
else if(format == PointGFp::HYBRID)
{
SecureVector<byte> result;
result.push_back(0x06 | static_cast<byte>(y.get_bit(0)));
result += bX;
result += bY;
return result;
}
else
throw Invalid_Argument("illegal point encoding format specification");
}
/**
* Serialize a Certificate Verify message
*/
SecureVector<byte> Certificate_Verify::serialize() const
{
SecureVector<byte> buf;
const u16bit sig_len = signature.size();
buf.push_back(get_byte(0, sig_len));
buf.push_back(get_byte(1, sig_len));
buf += signature;
return buf;
}