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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.
For example, encryption using an oversimplified three-round cipher can be written as = ((())), where C is the ciphertext and P is the plaintext. Typically, rounds R 1 , R 2 , . . . {\displaystyle R_{1},R_{2},...} are implemented using the same function, parameterized by the round constant and, for block ciphers , the round key from the key ...
In 1929, Lester S. Hill developed the Hill cipher, which uses matrix algebra to encrypt blocks of any desired length. However, encryption is very difficult to perform by hand for any sufficiently large block size, although it has been implemented by machine or computer. This is therefore on the frontier between classical and modern cryptography.
Sometimes values are reported without the normalizing denominator, for example 0.067 = 1.73/26 for English; such values may be called κ p ("kappa-plaintext") rather than IC, with κ r ("kappa-random") used to denote the denominator 1/c (which is the expected coincidence rate for a uniform distribution of the same alphabet, 0.0385=1/26 for ...
CMEA – cipher used in US cellphones, found to have weaknesses. CS-Cipher – 64-bit block; Data Encryption Standard (DES) – 64-bit block; FIPS 46-3, 1976; DEAL – an AES candidate derived from DES; DES-X – a variant of DES to increase the key size. FEAL; GDES – a DES variant designed to speed up encryption; Grand Cru – 128-bit block
Cryptography in an Algebraic Alphabet (1929) [4] 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).
In cryptography, unicity distance is the length of an original ciphertext needed to break the cipher by reducing the number of possible spurious keys to zero in a brute force attack. That is, after trying every possible key , there should be just one decipherment that makes sense, i.e. expected amount of ciphertext needed to determine the key ...
That is, given a plaintext and a ciphertext it is infeasible to find a key that encrypts the plaintext to the ciphertext. But, given a ciphertext and a key a matching plaintext can be found simply by using the block cipher's decryption function. Thus, to turn a block cipher into a one-way compression function some extra operations have to be added.