Safe Encrypt/Decrypt Functions

[eluser]CodeIgniterNewbie[/eluser]
Given an input string (will actually be an integer value) and an encryption key, I need to encrypt the input string in such a way that the resulting string is:

1. URL safe (my permitted URI characters is currently: a-z 0-9~%.:_-)
2. Filename safe (meaning, it only uses valid directory/filename characters)
3. FTP account username safe
4. Email account username safe

Then, given the encrypted string and the same encryption key, decrypt the the string into its unencrypted form.

This is not intended to be a security measure. Thanks.

[eluser]InsiteFX[/eluser]
Take a look at CodeIgniters Encryption Class.

Encryption Class

InsiteFX