Cryptanalysis

Cryptanalysis (from the Greek kryptós, "hidden", and analýein, "to loosen" or "to untie") is the study of methods for obtaining the meaning of encrypted information, without access to the secret information which is normally required to do so. Typically, this involves finding a secret key. In non-technical language, this is the practice of codebreaking or cracking the code, although "break" can also mean just a part of a complete solution.

People have been making and breaking codes for many centuries. In the 1930s specialized machines were invented to do the calculations. Code-breaking machines such as the Colossus computer were important during World War II. Computers were the main tool of cryptanalysis in the Cold War and later.

Cryptanalysis Media

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  Reconstruction of the appearance of cyclometer, a device used to break the encryption of the Enigma machine. Based on sketches in Marian Rejewski's memoirs.

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  First page of Al-Kindi's 9th century Manuscript on Deciphering Cryptographic Messages

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  The decrypted Zimmermann Telegram.

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  The Bombe replicated the action of several Enigma machines wired together. Each of the rapidly rotating drums, pictured above in a Bletchley Park museum mockup, simulated the action of an Enigma rotor.

Related pages

• Code
• Cryptography

References

• Helen Fouché Gaines, "Cryptanalysis", 1939, Dover. ISBN 0-486-20097-3

Other websites

• Basic Cryptanalysis
• Simon Singh's crypto corner Archived 2008-05-09 at the Wayback Machine
• Distributed Computing Projects
• UltraAnvil tool for attacking simple substitution ciphers Archived 2007-01-28 at the Wayback Machine
• A lot of real encrypted messages on newsgroups
• A javascript codesystems solver for many types of ciphers, with examples Archived 2008-07-07 at the Wayback Machine
• The National Museum of Computing Cipher Challenge Archived 2008-08-01 at the Wayback Machine