National Cipher Challenge - AbsoluteAstronomy.com

The National Cipher Challenge is an annual cryptographic

Cryptography

Cryptography is the practice and study of techniques for secure communication in the presence of third parties...

competition organised by the University of Southampton

University of Southampton

The University of Southampton is a British public university located in the city of Southampton, England, a member of the Russell Group. The origins of the university can be dated back to the founding of the Hartley Institution in 1862 by Henry Robertson Hartley. In 1902, the Institution developed...

School of Mathematics. Competitors attempt to break cryptograms published on the competition website. In the 2007/08 challenge, 1301 teams participated. Participants must be in full time education and aged 18 or under on the 31st August of the year that the challenge finishes.

Format

The competition is organised into eight challenges, which are further subdivided into parts A and B. The part A challenge consists of a relatively simple cryptogram that is intended for beginning cryptographers. In later challenges the cryptograms become harder to break. In the past, part A cryptograms have been encrypted with the Caesar cipher

Caesar cipher

In cryptography, a Caesar cipher, also known as a Caesar's cipher, the shift cipher, Caesar's code or Caesar shift, is one of the simplest and most widely known encryption techniques. It is a type of substitution cipher in which each letter in the plaintext is replaced by a letter some fixed number...

, the Affine cipher

Affine cipher

The affine cipher is a type of monoalphabetic substitution cipher, wherein each letter in an alphabet is mapped to its numeric equivalent, encrypted using a simple mathematical function, and converted back to a letter...

, the Keyword cipher

Keyword cipher

A keyword cipher is a form of monoalphabetic substitution. A keyword is used as the key, and it determines the letter matchings of the cipher alphabet to the plain alphabet. Repeats of letters in the word are removed, then the cipher alphabet is generated with the keyword matching to A,B,C etc...

, the Transposition cipher

Transposition cipher

In cryptography, a transposition cipher is a method of encryption by which the positions held by units of plaintext are shifted according to a regular system, so that the ciphertext constitutes a permutation of the plaintext. That is, the order of the units is changed...

and the Vigenère cipher

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 part B challenges are intended to be harder. These begin with relatively simple substitution ciphers, including the Bacon cipher and Polybius square

Polybius square

In cryptography, the Polybius square, also known as the Polybius checkerboard, is a device invented by the Ancient Greek historian and scholar Polybius, described in , for fractionating plaintext characters so that they can be represented by a smaller set of symbols.-Basic form :The original square...

, before moving on to transposition cipher

Transposition cipher

s, Playfair cipher

Playfair cipher

The Playfair cipher or Playfair square is a manual symmetric encryption technique and was the first literal digraph substitution cipher. The scheme was invented in 1854 by Charles Wheatstone, but bears the name of Lord Playfair who promoted the use of the cipher.The technique encrypts pairs of...

s and polyalphabetic ciphers such as the Vigenère cipher

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 Autokey cipher

Autokey cipher

An autokey cipher is a cipher which incorporates the message into the key. There are two forms of autokey cipher: key autokey and text autokey ciphers. A key-autokey cipher uses previous members of the keystream to determine the next element in the keystream...

and the Alberti cipher

Alberti cipher

- Leon Battista Alberti :Created in the 15th century , it was the peak of cryptography at that time. Its inventor was Leon Battista Alberti, an illegitimate son of an Italian nobleman. He was also interested in painting and writing, though he is probably best known for his architecture...

. In the later stages of the competition, the ADFGVX cipher

ADFGVX cipher

In cryptography, the ADFGVX cipher was a field cipher used by the German Army during World War I. ADFGVX was in fact an extension of an earlier cipher called ADFGX. Invented by Colonel Fritz Nebel and introduced in March 1918, the cipher was a fractionating transposition cipher which combined a...

, the Solitaire cipher, the Double Playfair cipher, the Hill cipher

Hill cipher

In classical cryptography, the Hill cipher is a polygraphic substitution cipher based on linear algebra. Invented by Lester S. Hill in 1929, it was the first polygraphic cipher in which it was practical to operate on more than three symbols at once. The following discussion assumes an elementary...

, the Book cipher

Book cipher

A book cipher is a cipher in which the key is some aspect of a book or other piece of text; books being common and widely available in modern times, users of book ciphers take the position that the details of the key is sufficiently well hidden from attackers in practice. This is in some ways an...

and versions of the Enigma

Enigma machine

An Enigma machine is any of a family of related electro-mechanical rotor cipher machines used for the encryption and decryption of secret messages. Enigma was invented by German engineer Arthur Scherbius at the end of World War I...

and Fialka

Fialka

In cryptography, Fialka is the name of a Cold War-era Soviet cipher machine. A rotor machine, the device uses 10 rotors, each with 30 contacts along with mechanical pins to control stepping. It also makes use of a punched card mechanism. "Fialka" means "violet" in Russian...

cipher machines have all been used. The 2009 challenge ended with a Jefferson Disk cipher, and the most recent challenge ended with the Solitaire Cipher.

Prizes

£25 cash prizes are awarded to eight random entrants who submit a correct solution for each part A of the challenge. Leaderboards for the part B challenges are also compiled, based on how accurate solutions are and how quickly the entrant broke the cipher. Prizes are awarded to the top three entrants at the end of the challenge. In the 2009/10 challenge, the sponsors provided several prizes: IBM provided iPod Touches to each member of the team winning the Team Prize, Trinity College provided a cash prize of £700, and GCHQ provided a cash prize of £1000. In previous years prizes such as an IBM Thinkpad laptop have been awarded.

After the challenge the winners of the top prizes and other randomly selected entrants are invited to a day held at Bletchley Park

Bletchley Park

Bletchley Park is an estate located in the town of Bletchley, in Buckinghamshire, England, which currently houses the National Museum of Computing...

consisting of lectures (with subjects such as the Semantic Web, World War II

World War II

World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...

cryptography and computer programming

Computer programming

Computer programming is the process of designing, writing, testing, debugging, and maintaining the source code of computer programs. This source code is written in one or more programming languages. The purpose of programming is to create a program that performs specific operations or exhibits a...

) and the prize-giving ceremony.

Current sponsors of the competition include GCHQ, IBM

IBM

International Business Machines Corporation or IBM is an American multinational technology and consulting corporation headquartered in Armonk, New York, United States. IBM manufactures and sells computer hardware and software, and it offers infrastructure, hosting and consulting services in areas...

, British Computer Society

British Computer Society

The British Computer Society, is a professional body and a learned society that represents those working in Information Technology in the United Kingdom and internationally...

, Trinity College, Cambridge

Trinity College, Cambridge

Trinity College is a constituent college of the University of Cambridge. Trinity has more members than any other college in Cambridge or Oxford, with around 700 undergraduates, 430 graduates, and over 170 Fellows...

, Cambridge University Press

Cambridge University Press

Cambridge University Press is the publishing business of the University of Cambridge. Granted letters patent by Henry VIII in 1534, it is the world's oldest publishing house, and the second largest university press in the world...

and EPSRC.

External links

The source of this article is wikipedia, the free encyclopedia. The text of this article is licensed under the GFDL.