These are my solutions to some of the CS50 course's problem sets.
CS50 is a fantastic course and I really recommend it, even if you don't enroll (I didn't).
These problem sets are based on the "Hacker Edition."
Problem Set 2 focuses on cryptography. crack.c accepts an old-style *nix password from /etc/passwd as an argument and attempts a brute-force attack on it using a dictionary file (in this case, the one included in /usr/share/dict/words). I've also include a list of the 10,000 most common passwords, stored in 10k.txt. Just change the code if you want to use it.
This is in two parts. The first is a program that resizes a 24-bit BMP (resize.c), and takes the resize factor as an argument.
The second program, recover.c, reads a forensic image (I didn't include the 15mb image here, but you can get it at the course website) and recovers a bunch of JPEGs from it by looking for the 4 bytes that demarcate a JPEG and routing them to a file.
The "sort" folder contains sortnsearch.h which is a collection of searching and sorting algorithms mentioned in one of the lectures. This wasn't a requirement but I wanted to get a handle on the workings of insertion sort, merge sort, etc.