EVP_PKT_EXCH
ret = EVP_PK_EC|EVP_PKT_SIGN|EVP_PKT_EXCH;
ret = EVP_PK_DH|EVP_PKT_EXCH;
ret = EVP_PKT_EXCH|EVP_PKT_SIGN;
!(has_bits(i, EVP_PK_DH|EVP_PKT_EXCH) || (nid == NID_dhKeyAgreement))) {