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Hacker Professional Ebook part 191

Ebook giới thiệu các công cụ và đồ nghề cần thiết cho việc Hack-Security. Ebook gồm có 1177 bài viết trong 28 chủ đề chính Phần 19: 10 part gồm Tools and toys for Hacking. | 5.6 Is DES a group It has been frequently asked whether DES encryption is closed under composition i.e. is encrypting a plaintext under one DES key and then encrypting the result under another key always equivalent to a single encryption under a single key Algebraically is DES a group If so then DES might be weaker than would otherwise be the case see 39 for a more complete discussion. However the answer is no DES is not a group 18 this issue was settled only recently after many years of speculation and circumstantial evidence. This result seems to imply that techniques such as triple encryption do in fact increase the security of DES. RSA Laboratories is the research and consultation division of RSA Data Security Inc. the company founded by the inventors of the RSA public-key cryptosystem. RSA Laboratories reviews designs and implements secure and efficient cryptosystems of all kinds. Its clients include government agencies telecommunications companies computer manufacturers software developers cable TV broadcasters interactive video manufacturers and satellite broadcast companies among others. For more information about RSA Laboratories call or write to RSA Laboratories 100 Marine Parkway Redwood City CA 94065 415 595-7703 415 595-4126 fax PKCS RSAREF and RSA Laboratories are trademarks of RSA Data Security Inc. All other trademarks belong to their respective companies. This document is available in ASCII Postscript and Latex formats via anonymous FTP to rsa.com pub faq. Please send comments and corrections to faq-editor@rsa.com. DISTRIBUTION How to obtain this document This document has been brought to you in part by CRAM involved in the redistribution of valuable information to a wider USENET audience see below . The most recent version of this document can be obtained via the author s instructions above. The following directions apply to retrieve the possibly less-current USENET FAQ version. FTP --- This FAQ is available from the standard FAQ server .