Need help to encrypt and decrypt an external text

[craftycs]

I'm hoping this is the right forum for my question and that this OS
software is the solution.
I have a client who want's a flash file that will be be edited via a
web interface that text file will be pulled into flash to display the
required information (user name and Company logo). The text file will
be encrypted and packaged with a PDF that contains the flash file for
download. The flash file inside the PDF needs to decrypt the text file
and display the required information. I have never done anythign like
this before so not even sure where to start.

Hope someone can help

Kind regards
Paul