BN_CTX_secure_new_ex
return BN_CTX_secure_new_ex(NULL);
BN_CTX *ctx = BN_CTX_secure_new_ex(eckey->libctx);
&& (ctx = new_ctx = BN_CTX_secure_new_ex(group->libctx)) == NULL)
&& (ctx = new_ctx = BN_CTX_secure_new_ex(group->libctx)) == NULL)
BN_CTX *BN_CTX_secure_new_ex(OSSL_LIB_CTX *ctx);
bnctx = BN_CTX_secure_new_ex(ossl_rsa_get0_libctx(rsa_pub));