I need to find (or write) a tool that decrypts DES encrypted image files.
As an input it will take the encrypted DES file, and the key (which will be supplied by the user). It should then be possible to decrypt the file using the standard implementation of DES.
I have programmed in C++ a while ago, but I am a bit rusty. Can anyone help me with where I should start if I needed to program this in C++? I don't want to be reproducing code if this has been done before.
Any help or indicators would be really appreciated.