EVP_PKEY_meth_set_public_check
OSSL_DEPRECATEDIN_3_0 void EVP_PKEY_meth_set_public_check(EVP_PKEY_METHOD *pmeth, int (*check)(EVP_PKEY *pkey));
EVP_PKEY_meth_set_public_check(custom_pmeth, pkey_custom_pub_check);