Cracking Codes with Python

20HACKING THE VIGENÈRE CIPHER

“Privacy is an inherent human right, and a requirement for maintaining the human condition with dignity and respect.”—Bruce Schneier, cryptographer, 2006

Two methods exist to hack the Vigenère cipher. One method uses a brute-force dictionary attack to try every word in the dictionary file as the Vigenère key, which works only if the key is an English word, such as RAVEN or DESK. The second, more sophisticated method, which was used by the 19th-century mathematician Charles Babbage, works even when the key is a random group of letters, such as VUWFE or PNFJ. In this chapter, we’ll write programs to hack the Vigenère ...