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The Playfair cipher or Playfair square or Wheatstone–Playfair cipher is a manual symmetric encryption technique and was the first literal digram substitution cipher. The scheme was invented in 1854 by Charles Wheatstone, but bears the name of Lord Playfair for promoting its use. The technique encrypts pairs of letters ( bigrams or digrams ...
The Two-square cipher, also called double Playfair, is a manual symmetric encryption technique. [1] It was developed to ease the cumbersome nature of the large encryption/decryption matrix used in the four-square cipher while still being slightly stronger than the single-square Playfair cipher . The technique encrypts pairs of letters ...
Polybius square. The Polybius square, also known as the Polybius checkerboard, is a device invented by the ancient Greeks Cleoxenus and Democleitus, and made famous by the historian and scholar Polybius. [ 1] The device is used for fractionating plaintext characters so that they can be represented by a smaller set of symbols, which is useful ...
4 4 3 3 3 5 3 2 4 3 1 3 5 5 3 1 2 3 2 5 Then divided up into pairs again, and the pairs turned back into letters using the square: 44 33 35 32 43 13 55 31 23 25 U A E O L W R I N S In this way, each ciphertext character depends on two plaintext characters, so the bifid is a digraphic cipher, like the Playfair cipher. To decrypt, the procedure ...
John Playfair FRSE, FRS (10 [citation needed] March 1748 – 20 July 1819) was a Church of Scotland minister, remembered as a scientist and mathematician, and a professor of natural philosophy at the University of Edinburgh. He is best known for his book Illustrations of the Huttonian Theory of the Earth (1802), which summarised the work of ...
ADFGVX cipher. In cryptography, the ADFGVX cipher was a manually applied field cipher used by the Imperial German Army during World War I. It was used to transmit messages secretly using wireless telegraphy. ADFGVX was in fact an extension of an earlier cipher called ADFGX which was first used on 1 March 1918 on the German Western Front.
Confusion in a symmetric cipher is obscuring the local correlation between the input ( plaintext ), and output ( ciphertext) by varying the application of the key to the data, while diffusion is hiding the plaintext statistics by spreading it over a larger area of ciphertext. [ 2] Although ciphers can be confusion-only ( substitution cipher ...
In cryptanalysis, frequency analysis (also known as counting letters) is the study of the frequency of letters or groups of letters in a ciphertext. The method is used as an aid to breaking classical ciphers . Frequency analysis is based on the fact that, in any given stretch of written language, certain letters and combinations of letters ...