CastToBool() sign bug? #1638

If I understand the MPI format correctly, the bit (0x80) used to indicate a negative value is stored at the beginning of the bytestream, not the end. MPI format is big endian, most-significant bit (MSB) first, and the sign bit precedes all that.

CastToBool() appears to check for the sign bit at the end of the bytestream, rather than the beginning:

        // Can be negative zero
        if (i == vch.size()-1 && vch[i] == 0x80)
            return false;

Nevermind. CBigNum::getvch() reverses the string (big -> little endian), so the sign bit would indeed be at the end.