web service for processing files

Not sure, really, where to ask this - and Rails is the first thing I think of when I want to wireframe something and know, due to the corporate world, it will end up in production anyway. (And that's ok.)

I need a service that will process files over our network (https). Been needing a way to have a centralized encryption engine for our various interfaces - files sent to vendors, processed in from them, too. There are multiple machines that may be processing files in/out and I want one central keyring, one central encryption binary (currently gnupg) and whatnot.

So I thought about a service driven application that could, in a nutshell, be a wrapper for the gnupg binary.

If there is anything out there that does this already, do say so. The geek inside, however, just wants to write my own.

Thoughts? Do I use SOAP or REST? It's not really that I want to use posts/gets...