int EVP_SIGNATURE_is_a(const EVP_SIGNATURE *signature, const char *name);
OSSL_PROVIDER *EVP_SIGNATURE_provider(const EVP_SIGNATURE *signature);
void EVP_SIGNATURE_do_all_provided(OPENSSL_CTX *libctx,
int EVP_SIGNATURE_is_a(const EVP_SIGNATURE *signature, const char *name);
OSSL_PROVIDER *EVP_SIGNATURE_provider(const EVP_SIGNATURE *signature);
void EVP_SIGNATURE_do_all_provided(OPENSSL_CTX *libctx,