National Cipher Challenge
The National Cipher Challenge is an annual cryptographic competition organised by the University of Southampton School of Mathematics. Competitors attempt to break cryptograms published on the competition website. In the 2017, more than 7,500 students took part in the competition. Participants must be in full-time school level education in order to qualify for prizes. Format The competition is organised into eight to ten challenges, which are further subdivided into parts A and B. The part A challenge consists of a comparatively simpler cryptogram, and usually provides some useful information to assist in the solving of part B. Part B is usually more complex. In later challenges the cryptograms become harder to break. In the past, part A cryptograms have been encrypted with the Caesar cipher, the Affine cipher, the Keyword cipher, the Transposition cipher, the Vigenère cipher and the 2x2 Hill cipher. The part B challenges are intended to be harder. These begin with relatively simple substitution ciphers, including the Bacon cipher and Polybius square, before moving on to transposition ciphers, Playfair ciphers and polyalphabetic ciphers such as the Vigenère cipher, the Autokey cipher and the Alberti cipher. In the later stages of the competition, the ADFGVX cipher, the Solitaire