Yikes, yes somehow our data got crossed.
this should be fixed shortly.
OK, so encryption doesn't easily work. Here's what I recommend for something like Credit cards.
1. DO NOT connect the db to the Intnernet or any public network. I use multi-homed web servers and the db is never directly accessable from the Internet.
2. Use asymetric encryption. PGP, is the freee one, but there are lots of solutions out there to allow you to build an asymmetric solution. Store the public key on the web server for storing the data and the private key on an internal server that will handle the processing. This keeps the "decryption" key 2 computers behind the Internet. Be sure you escrow a copy of this private key somewhere offline, tape, cd etc.
3. If you must store the credit card in the db, I'd remove select/update rights from it for the web server. Use a separate server to auth the transaction and a separate user/role to do this that has select rights.