Издательство: | Книга по требованию |
Дата выхода: | июль 2011 |
ISBN: | 978-6-1303-5094-9 |
Объём: | 68 страниц |
Масса: | 123 г |
Размеры(В x Ш x Т), см: | 23 x 16 x 1 |
High Quality Content by WIKIPEDIA articles! 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 mxn 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.
Данное издание не является оригинальным. Книга печатается по технологии принт-он-деманд после получения заказа.