Crank is a project to provide a GUI toolkit to facilitate (and where possible, automate) the breaking of classical (pen-and-paper) cryptosystems. Initial focus is on the cryptanalysis of monoalphabetic substitution ciphers.
I really like this app! Makes a great replacement for noodling on pen and paper when working from a textbook...
A tool for securing DNS communications between a client and a DNS resolver.
A polyhedral extraction tool (PET).