Cracking Codes with Python

18PROGRAMMING THE VIGENÈRE CIPHER

“I believed then, and continue to believe now, that the benefits to our security and freedom of widely available cryptography far, far outweigh the inevitable damage that comes from its use by criminals and terrorists.”—Matt Blaze, AT&T Labs, September 2001

The Italian cryptographer Giovan Battista Bellaso was the first person to describe the Vigenère cipher in 1553, but it was eventually named after the French diplomat Blaise de Vigenère, one of many people who reinvented the cipher in subsequent years. It was known as “le chiffre indéchiffrable,” which means “the indecipherable cipher,” and remained unbroken ...