Although most popular protocols are secured with encryption, at the beginning it required new standard approval, development of necessary libraries and their wrappers for other languages, modifications in client and server applications. More than, these modern protocols co-exist with their unencrypted counterparts.
USCoGa is a technique to add security layer on top of Internet layer without any modifications needed for applications on both ends of network connections.
On server side there are no more necessary than tunneling some secured port to a regular non-secured service. It can be done with stunnel or any other utility. Only SSL encryption is taken into consideration in this article, but it is not a limitation of USCoGa.
On client side there is a lot of configuration. Essential functionality needed: