How would you make a simple cipher for an integer in rails?

I have an integer output from a private controller action that I would like to store 'encrypted' in my database. What methods would you use to codify this integer such that I can retrieve u开发者_StackOverflowp to ~200 of these numbers easily and quickly to be served in a view to the right user?

Have a look at http://github.com/spikex/strongbox

You want to use a SHA1 hash? Or a flagmap? Or what is 'encrypted' exactly?