Vigenère Cipher

The Vigenère cipher is a method of encrypting alphabetic text by using a series of different Caesar ciphers based on the letters of a keyword. It is a simple form of polyalphabetic substitution.

The Vigenère cipher has been reinvented many times. The method was originally described by Giovan Battista Bellaso in his 1553 book La cifra del. Sig. Giovan Battista Bellaso; however, the scheme was later misattributed to Blaise de Vigenère in the 19th century, and is now widely known as the "Vigenère cipher".

This cipher is well known because while it is easy to understand and implement, it often appears to beginners to be unbreakable; this earned it the description le chiffre indéchiffrable (French for 'the indecipherable cipher'). Consequently, many people have tried to implement encryption schemes that are essentially Vigenère ciphers, only to have them broken.

Read more about Vigenère Cipher:  History, Description, Algebraic Description, Cryptanalysis, Variants

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Vigenère Cipher - Variants
... The running key variant of the Vigenère cipher was also considered unbreakable at one time ... The problem with the running key Vigenère cipher is that the cryptanalyst has statistical information about the key (assuming that the block of text is in a known language) and that ... which is truly random, is at least as long as the encrypted message and is used only once, the Vigenère cipher is theoretically unbreakable ...

Famous quotes containing the word cipher:

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    Ralph Waldo Emerson (1803–1882)