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…