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Unformatted text preview: the world. The ISO almost, but not quite, created an RSA digital-signature standard; RSA is in an information annex to ISO 9796 . The French banking community standardized on RSA , as have the Australians . The United States currently has no standard for public-key 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 . Patents
The RSA algorithm is patented in the United States , but not in any other country. PKP licenses the patent, along with other public-key cryptography patents (see Section 25.5). The U.S. patent will expire on September 20, 2000. 19.4 Pohlig-Hellman
The Pohlig-Hellman encryption scheme  is similar to RSA. It is not a symmetric algorithm, because different keys are used for encryption and decryption. It is not a public-key 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 © 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)
Brief Full Advanced Search Search Tips (Publisher: John Wiley & Sons, Inc.) Author(s): Bruce Schneier ISBN: 0471128457 Publication Date: 01/01/96 Search this bo...
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