ecccdh_serialize_pub_key
ATTRIBUTE_WARN_UNUSED_RET int ecccdh_serialize_pub_key(const ec_pub_key *our_pub_key, u8 *buff, u8 buff_len);
ret = ecccdh_serialize_pub_key(&(kp.pub_key), serialized_pub_key, serialized_pub_key_len);
ret = ecccdh_serialize_pub_key(&ourpub_key, serialized_pub_key, serialized_pub_key_size);
ret = ecccdh_serialize_pub_key(&ourpub_key_check, serialized_pub_key_check, serialized_pub_key_size);