Collecting Credit Card Information - not to collect payment

Question

I am working in PHP on a Linux server with MySQL.

I have a requirement (that I have attempted to talk them out of) to collect credit card information from users so tha

Answer 1

1. Make sure your server is as secure as possible and prove that it isn't already compromised. None of this will really work well if you have a compromised server.

2. Use SSL to protect this information during transit.

3. Encrypt these details immediately upon receipt. This will help protect it at rest. If possible, encrypt it with a public key for a key pair where the private key (used for decryption) is not on your server. This could easily be that you place this information into the body of the email that you're required to send, then encrypt the body with public-key encryption where your client has the private key. (You could use PGP here). In this way, the data is help on your server as briefly as possible, then once off your server, is accessible only by your client. If you use a symmetric encryption algorithm, then your key will necessarily also be on your server somewhere (on disk, in memory, etc.), which could be obtained and used by an attacker to regain access to the details.

This isn't an endorsement, per se, but I have used this before in similar situations with good results: http://www.pgp.com/products/commandline/

Remember that there are always security holes, but you'll be raising a large barrier against attacks with these steps. I might also add that you look into a system integrity solution like Trip Wire from the immediate build of your server. And of course, ensure that all of your passwords are strong.