42 School project. From the subject (also available in french):
The goal of this project is to code a program that will, firstly, encrypt a program give as parameter. Only 64 bits ELF files will be managed here.
A new program called “woody” will be generated from this execution. When this new program (woody) will be executed, it will have to be decrypted to be run. Its execution has to be at any point identical to the program given as parameter in the last step.