applied cryptography - protocols, algorithms, and source code in c

The second incarnation of lucifer is even weaker 170

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Unformatted text preview: 5 12 6 2 11 1 7 1 8 9 10 5 3 15 0 12 3 7 14 1 15 6 12 8 5 11 8 13 2 10 12 3 5 6 15 0 12 2 9 1 6 11 5 0 3 7 14 13 8 0 5 3 12 9 1 8 11 13 14 4 7 2 6 15 10 4 1 5 11 3 0 8 7 14 13 9 0 5 10 15 2 13 4 14 7 11 1 8 7 1 0 14 3 9 14 4 2 15 12 1 5 6 11 8 4 14 11 8 15 12 6 10 9 5 0 3 9 3 7 10 1 8 2 11 15 5 12 6 2 4 13 1 6 5 9 0 12 15 3 10 Previous Table of Contents Next Products | Contact Us | About Us | Privacy | Ad Info | Home Use of this site is subject to certain Terms & Conditions, Copyright © 1996-2000 EarthWeb Inc. All rights reserved. Reproduction whole or in part in any form or medium without express written permission of EarthWeb is prohibited. Read EarthWeb's privacy statement. To access the contents, click the chapter and section titles. Applied Cryptography, Second Edition: Protocols, Algorthms, and Source Code in C (cloth) Go! Keyword Brief Full Advanced Search Search Tips (Publisher: John Wiley & Sons, Inc.) Author(s): Bruce Schneier ISBN: 0471128457 Publication Date: 01/01/96 Search this book: Go! Previous Table of Contents Next ----------- Here is a method to use 48 additional key bits to generate S-boxes that are resistant to both linear and differential cryptanalysis [165]. (1) Rearrange the DES S-boxes: 24673158. (2) Select 16 of the remaining key bits. If the first bit is 1, swap the first two rows of S-box 1 with the last two rows of S-box 1. If the second bit is a 1, swap the first eight columns of S-box 1 with the second eight columns of S-box 1. Do the same to S-box 2 with the third and fourth key bits. Do the same with S-boxes 3 through 8. (3) Take the remaining 32 key bits. XOR the first four with every entry of S-box 1, the second four with every entry of S-box 2 and so on. The complexity of a differential cryptanalysis attack against this system is 251; the complexity of a linear cryptanalysis attack is 253. The complexity of exhaustive search is 2102. What is neat about this DES variant is that it can be implemented in existing hardware. Several DES chip vendors sell DES chips with loadable S-boxes. This S-box generation method can be do...
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