Hey Jib,
I did an encryption job about 2 years ago. (see attached)
I opened the project, had to update it to VS 2008, and verified it still worked.
I don't remember why I did all that I did, but I did not need the DESCryptoServiceProvider class.
Feel free to poke around my code. It should still work as is. The security key will be missing when you first run it, but the code will prompt you to create a new one and go from there.
Hope it helps. jp2crypt.zip