Is there a hacking sim that can meat our needs?

My friends and I are looking for a hacking sim. We're looking for something legit. Not a game like "Hacker Experience." Before we have used the computercraft mod for minecraft witch is pretty much exactly what we want but we just want the computer and network emulation. Computercraft uses the Lua language with some proprietary functions and we're able to program things like Hashing software, encryption, brute force attacks from scratch. We're competent enough to learn other languages. Essentially what we want is a dumbed down computer emulator with minimal OS(basically just a shell) and the capable of easily send traffic to each other without the trouble of protocols all in a isolated invention. I know that's a lot to ask for but is there anything close?