NOTICE: Citizendium is still being set up on its newer server, treat as a beta for now; please see here for more.
Citizendium - a community developing a quality comprehensive compendium of knowledge, online and free. Click here to join and contribute—free
CZ thanks our previous donors. Donate here. Treasurer's Financial Report -- Thanks to our content contributors. --

Caesar cipher

From Citizendium, the Citizens' Compendium
Jump to: navigation, search
This article is developing and not approved.
Main Article
Related Articles  [?]
Bibliography  [?]
External Links  [?]
Citable Version  [?]
This editable Main Article is under development and not meant to be cited; by editing it you can help to improve it towards a future approved, citable version. These unapproved articles are subject to a disclaimer.

An early and simple substitution cipher was the Caesar cipher, in which each letter in the plaintext was replaced by a letter some fixed number of positions further down the alphabet. It was named after Julius Caesar who used the cipher with a shift of 3 in order to communicate with his generals during his various military campaigns.

For example, with a shift of 3, "BAD DOG" would become "EDG GRJ". This type of encryption is trivial to cryptanalize using frequency analysis.

One Caesar cipher is still in use; rot 13 is used to hide "spoilers" such as the ending of a movie in Internet discussions. It is not used for any serious security.