encrypt/decrypt environment variable

When a person logs into our site and submits a form, the data are appended to an ASCII database (by a Perl/CGI program). The site operates via SSL such that the form data are encrypted during transfer. To protect the data residing on the server, I'd like to encrypt the remote_user environment variable, with the ability to decrypt it later, once I have downloaded the database file to my hard drive. How can I do that?

Thanks in advance for any help you can offer.

Atar