Simplified DES Encryption algorithm originally intended for a software security course at Ohio University. It is a direct implementation of the algorithm, using the same permutations and steps as in the original paper.
It may not be the most efficient in the world, but it works! Lots of bit shifting and such.
The program is intended to take in standard input, but can work with a file as well. As there is no way of knowing when you reach the end of the input, once you are done you have to give it the ole' Ctrl-C. Standard use:
$ ./des_encrypt 10_BIT_KEYIf you want to read in a file, you can either pipe it in using standard input OR you can give a command line argument for it to actually close.
$ ./des_encrypt 10_BIT_KEY FILENAMESample usage where filename contains: "Hello World!"
$ ./des_encrypt 0x2aa filename
�迿 �( Q����Yes, it's unreadable. Good thing that's what we wanted.