Example of Sodium encryption library
This code is built to demonstrate the cross platform capability of the library, I couldn't find any and thought this might help some people. It's a well documented crypto library so it's not difficult to understand at all.
This is an example of asymmetric encryption from a PHP client to c++, I have not provided the php code yet as I've not fully finished my work. However with this it should be much easier to impliment, all you have to do is send the keys to the cpp program or from the cpp program back to php through whatever means. ^ Much easier said than done to be cryptographically secure