On Mon, 2022-01-03 at 01:51 +0100, Wolf wrote: > Greetings, > > I'm trying to port my program to openssl 3.0 and in the process I > need > to replace EC_GROUP_get_degree(EC_KEY_get0_group(ec)) with something > that is not deprecated. I'm trying to use EVP_PKEY_get_int_param with > OSSL_PKEY_PARAM_EC_CHAR2_M, however it does not work. I'm assuming > I'm > just doing something wrong, but have no idea what. Would there be any > kind soul willing to point me in the right direction? You're using the secp384r1 curve which is a prime field curve. The OSSL_PKEY_PARAM_EC_CHAR2_M parameter can be obtained only for binary field curves. If you have a group NID for the curve of the EC key, you could use: EC_GROUP *group = EC_GROUP_new_by_curve_name_ex(NULL, NULL, nid); to create the group to call EC_GROUP_get_degree() on. Of course if you can have an EC key with arbitrary explicit group parameters, that would not work. But you can then use number of bits of the OSSL_PKEY_PARAM_EC_P parameter as the degree for prime field curves. -- Tomáš Mráz, OpenSSL
