The encryption/decryption is usually handled at the "connection" level, usually via SSL instead of being handled directly by the database. That way all of the communication (including connection parameters, username, password, etc) is held secure, instead of only the pure data portion.
Without knowing more about what you are trying to do, it is difficult for me to give you concrete advice. Your best bet is probably to investigate using either HTTPS: or some form of VPN such as IPSec or PPTP between the client and the server.
-PatP