S-Box: Cryptography, Symmetric-Key Algorithm, Block Cipher, Ciphertext, Claude Shannon, Confusion and Diffusion, Bit, Twofish, Key, Bruce Schneier, International Data Encryption Algorithm - Couverture souple

9786130350949: S-Box: Cryptography, Symmetric-Key Algorithm, Block Cipher, Ciphertext, Claude Shannon, Confusion and Diffusion, Bit, Twofish, Key, Bruce Schneier, International Data Encryption Algorithm

Couverture souple

ISBN 10 : 6130350945 ISBN 13 : 9786130350949

Editeur : Betascript Publishing, 2010

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Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. In cryptography, an S-Box (Substitution-box) is a basic component of symmetric key algorithms which performs substitution. In block ciphers, they are typically used to obscure the relationship between the key and the ciphertext �€” Shannon''s property of confusion. In many cases, the S-Boxes are carefully chosen to resist cryptanalysis. In general, an S-Box takes some number of input bits, m, and transforms them into some number of output bits, n: an m�—n S-Box can be implemented as a lookup table with 2m words of n bits each. Fixed tables are normally used, as in the Data Encryption Standard (DES), but in some ciphers the tables are generated dynamically from the key; e.g. the Blowfish and the Twofish encryption algorithms.

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