I am writing a c++ program that connects two computers over the net and makes them appear to be on a lan. Basically a stripped-down vpn. I was wondering if i could encrypt the data one each end before sending it and then decrypt when received.

I am using Micro$oft C++ 4.2 as it is all I have available. What is the best encryption? 128-bit DES? and how do I encrypt and decrypt. I use all the standard MFC libs that came with it.