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

5 peggy and victor repeat steps 1 through 4 n times if

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Unformatted text preview: hat is isomorphic to the original problem. She then uses her information and the random number to solve this new instance of the hard problem. (2) Peggy commits to the solution of the new instance, using a bit-commitment scheme. (3) Peggy reveals to Victor the new instance. Victor cannot use this new problem to get any information about the original instance or its solution. (4) Victor asks Peggy either to: (a) prove to him that the old and new instances are isomorphic (i.e., two different solutions to two related problems), or (b) open the solution she committed to in step (2) and prove that it is a solution to the new instance. (5) Peggy complies. (6) Peggy and Victor repeat steps (1) through (5) n times. Remember the camcorder in the cave protocol? You can do the same thing here. Victor can make a transcript of the exchange between him and Peggy. He cannot use this transcript to convince Carol, because he can always collude with Peggy to build a simulator that fakes Peggy’s knowledge. This argument can be used to prove that the proof is zero-knowledge. The mathematics behind this type of proof is complicated. The problems and the random transformation must be chosen carefully, so that Victor does not get any information about the solution to the original problem, even after many iterations of the protocol. Not all hard problems can be used for zero-knowledge proofs, but a lot of them can. 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:...
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