Encryption / Description Alphanumeric 16 digits

[eluser]WanWizard[/eluser]
Isn't it easier to genarate a hash, and store the rest in the database? Like p.e. the search option on this forum does?

Anyway, you can't limit the result of the encryption to a fixed length string, it is always going to depend on the input length.

A hash always has a fixed length. You could even decide to use only the first 16 characters of a hash, but than you will have to do some collision detection.

Otherwise, just use the encrypt library's encode/decode methods (see the docs).