I am an expert programmer with more than 10 years of experience in the realization of desktop applications based on C/C++/C# languages. In my professional activity, I have been involved in complex C/C++/C# projects on Windows and Linux platforms.
More or less I have understood what you need. I could define for you a programm in C++ which encrypt/decrypt a generic binary file; so you could use this programm by yourself, whenever you want, for any binary file you need to encrypt/decrypt.
If you want to discuss the project details, you can contact me for a chat conversation on Freelancer.com portal. If I am not online, you can send me a message to fix a meeting.