My old source code of the resource tool, written in C++, for the game Fantasy Tennis.
It decrypts .set files which are located inside the .res archives. It also encrypts the plain file again to the .set file.
To decrypt a .set file, just drag and drop it on the compiled application.
To encrypt it back after changes has been made, drag and drop the decrypted file on the compiled application.
Visual Studio 15 or later.