0 if the given secret key is invalid according to secp256k1_ec_seckey_verify. 1 otherwise Args: ctx: pointer to a context object In/Out: seckey: pointer to the 32-byte secret key to be negated. If the secret key is invalid according to secp256k1_ec_seckey_verify, this function returns 0 and seckey will be set to some unspecified value.
Negates a secret key in place.