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Hill's cipher machine, from figure 4 of the patent. 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 (though barely) to operate on more than three symbols at once.
The Hill cipher, invented in 1929 by Lester S. Hill, is a polygraphic substitution which can combine much larger groups of letters simultaneously using linear algebra. Each letter is treated as a digit in base 26 : A = 0, B =1, and so on.
Wichmann–Hill generator: 1982 B. A. Wichmann and D. I. Hill [7] A combination of three small LCGs, suited to 16-bit CPUs. Widely used in many programs, e.g. it is used in Excel 2003 and later versions for the Excel function RAND [8] and it was the default generator in the language Python up to version 2.2. [9] Rule 30: 1983 S. Wolfram [10]
Polygraphic substitution is a cipher in which a uniform substitution is performed on blocks of letters. When the length of the block is specifically known, more precise terms are used: for instance, a cipher in which pairs of letters are substituted is bigraphic.
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Table compares implementations of block ciphers. Block ciphers are defined as being deterministic and operating on a set number of bits (termed a block) using a symmetric key. Each block cipher can be broken up into the possible key sizes and block cipher modes it can be run with.
[8]: p.37 Classical ciphers are typically vulnerable to known-plaintext attack. For example, a Caesar cipher can be solved using a single letter of corresponding plaintext and ciphertext to decrypt entirely. A general monoalphabetic substitution cipher needs several character pairs and some guessing if there are fewer than 26 distinct pairs.
Lester S. Hill (1891–1961) was an American mathematician and educator who was interested in applications of mathematics to communications.He received a bachelor's degree (1911) and a master's degree (1913) from Columbia College and a Ph.D. from Yale University (1926).