_get_derived_key
ret = _get_derived_key(context, crypto, ENCRYPTION_USAGE(usage), &dkey);
ret = _get_derived_key(context, crypto, ENCRYPTION_USAGE(usage), &dkey);
ret = _get_derived_key(context, crypto, ENCRYPTION_USAGE(usage), &dkey);
ret = _get_derived_key(context, crypto, usage, key);
static krb5_error_code _get_derived_key(krb5_context, krb5_crypto,
ret = _get_derived_key(context, crypto, ENCRYPTION_USAGE(usage), &dkey);