Unformatted text preview: the world. The ISO almost, but not quite, created an RSA digitalsignature standard; RSA is in an information annex to ISO 9796 [762]. The French banking community standardized on RSA [525], as have the Australians [1498]. The United States currently has no standard for publickey encryption, because of pressure from the NSA and patent issues. Many U.S. companies use PKCS (see Section 24.14), written by RSA Data Security, Inc. A draft ANSI banking standard specifies RSA [61]. Patents
The RSA algorithm is patented in the United States [1330], but not in any other country. PKP licenses the patent, along with other publickey cryptography patents (see Section 25.5). The U.S. patent will expire on September 20, 2000. 19.4 PohligHellman
The PohligHellman encryption scheme [1253] is similar to RSA. It is not a symmetric algorithm, because different keys are used for encryption and decryption. It is not a publickey scheme, because the keys are easily derivable from each other; both the encryption and decryption keys must be kept secret. Like RSA, C = Pe mod n P = Cd mod n where ed a 1 (mod some complicated number) Unlike RSA, n is not defined in terms of two large primes, it must remain part of the secret key. If someone had e and n, they could calculate d. Without knowledge of e or d, an adversary would be forced to calculate e = logPC mod n We have already seen that this is a hard problem. 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 © 19962000 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)
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This note was uploaded on 10/18/2010 for the course MATH CS 301 taught by Professor Aliulger during the Fall '10 term at Koç University.
 Fall '10
 ALIULGER
 Cryptography

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