Crank 0.1.3

A powerful and extensible environment for solving classical (pen-and-paper) ciphers, providing as much automation as possible Classical ciphers include common schemes like monoalphabetic substitutions, where each letter of the alphabet is mapped to another (usually different) letter consistently through the text.
The first version of Crank (CRyptANalysis toolKit) is restricting itself to these special ciphers. Other algorithms forever devoid of Cranks attentions include Enigma, MurkelFish, RSA, DES, or anything else invented after 1900.
Crank has the concept of a source file (the ciphertext), and a view on that file (hopefully this becomes the cleartext). The view on the source is determined by the currently active plugin, which corresponds to a cryptanalysis tool.
The bottom text area in the main window is the view of the source after its been acted on by the tool, and the top part is before. For example, if its a monoalphabetic substitution decoder, if part of the key isnt complete, unmapped (i.e. still ciphertext) letters will be displayed in upper case, whilst decoded letters will appear as lower case.
The various key controls and statistics displays are meant to help you transform the key into the correct decoding one. There is also an automatic cracking tool which will attempt to crack the cipher for you.
Crank needs the cipher to have around 2-3000+ alphabetic characters to work reliably, but Ive had partial decryptions happen with texts as small as 67 letters.
Crank works by measuring the frequency of letters, pairs of letters and triples of letters, and comparing them to what you would expect to get in a sample of plaintext (English, in this case).
Crank tries small variations of a key to try and make the frequency counts of the transformed text match standard English frequencies.
System requirements:
- All versions of Crank require the GTK+ widget library