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

Weak keys because of the way the initial key is

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Unformatted text preview: Much has been written on efficient hardware and software implementations of the algorithm [997,81,533,534,437,738,1573,176,271,1572]. At this writing, the recordholder for the fastest DES chip is a prototype developed at Digital Equipment Corporation [512]. It supports ECB and CBC modes and is based on a GaAs gate array of 50,000 transistors. Data can be encrypted and decrypted at a rate of 1 gigabit per second, which translates to 16.8 million blocks per second. This is impressive. Table 12.9 gives the specifications for some commercial DES chips. Seeming discrepancies between clock speed and data rate are due to pipelining within the chip; a chip might have multiple DES engines working in parallel. The most impressive DES chip is VLSI’s 6868 (formerly called “Gatekeeper”). Not only can it perform DES encryption in only 8 clock cycles (prototypes in the lab can do it in 4 clock cycles), but it can also do ECB triple-DES in 25 clock cycles, and OFB or CBC triple-DES in 35 clock cycles. This sounds impossible to me, too, but I assure you it works. A software implementation of DES on an IBM 3090 mainframe can perform 32,000 DES encryptions per second. Most microcomputers are slower, but impressive nonetheless. Table 12.10 [603,793] gives actual results and estimates for various Intel and Motorola microprocessors. 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 ----------- 12.3 Security of DES People have lon...
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