I'd be happy to look over your previous encryption code. Like Doug pointed out, the liability is huge, but folks that are storing whole numbers are probably doing something like offline processing and should be aware that they're not necessarily doing the best thing. I can't use md5() or crypt(), though, because that's just a one way hash... no way to decrypt it. I thought about doing some obfuscation, but I didn't waste my time since it's not real security and anyone could reverse engineer it since Ubercart is open source.