'Check the public key and the private key.
The private key is optional (replace by None)'

def check_key(self, privkey, pubkey):

    (curve, pubkey_x, pubkey_y, i) = ECC._decode_pubkey(pubkey)
    if (privkey is None):
        raw_privkey = None
        curve2 = curve
    else:
        (curve2, raw_privkey, i) = ECC._decode_privkey(privkey)
    if (curve != curve2):
        raise Exception('Bad    public    and    private    key')
    return self.raw_check_key(raw_privkey, pubkey_x, pubkey_y, curve)
