Unformatted text preview: ent her identity from being revealed if she cheats. She can’t change either the uniqueness string or any of the identity strings, because then the bank’s signature will no longer be valid. The merchant will immediately notice that in step (6). Alice could try to sneak a bad money order past the bank, one on which the identity strings don’t reveal her name; or better yet, one whose identity strings reveal someone else’s name. The odds of her getting this ruse past the bank in step (3) are 1 in n . These aren’t impossible odds, but if you make the penalty severe enough, Alice won’t try it. Or, you could increase the number of redundant money orders that Alice makes in step (1). Can the merchant cheat? His chances are even worse. He can’t deposit the money order twice; the bank will notice the repeated use of the selector string. He can’t fake blaming Alice; only she can open any of the identity strings. 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 book:
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----------- Even collusion between Alice and the merchant can’t cheat the bank. As long as the bank signs the money order with the uniqueness string, the bank is assured of only having to make good on the money order once. What about the bank? Can it figure out that the money order it accepted from the merchant was the one it signed for Alice? Alice is protected by the blind signature protocol in steps (2) through (5). The bank...
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