This preview shows page 1. Sign up to view the full content.
Unformatted text preview: (p, q) == 1 */ (void)extended_euclidian(p, q, &a, &b); u = modexp ((p+1)/4, t, p-1); v = modexp ((q+1)/4, t, q-1); w = modexp (xt%p, u, p); z = modexp (xt%q, v, q); return (b*q*w + a*p*z) % n; 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:
Go! Previous Table of Contents Next
----------- Once you have x0, decryption is easy. Just set up the BBS generator and XOR the output with the ciphertext. You can make this scheme go even faster by using all the known secure bits of xi, not just the least significant bit. With this improvement, Blum-Goldwasser probabilistic encryption is faster than RSA while leaking no partial information about the plaintext. You can also prove that the difficulty of breaking this scheme is the same as the difficulty of factoring n. On the other hand, this scheme is totally insecure against a chosen-ciphertext attack. From the least significant bits of the right quadratic residues, it is possible to calculate the square root of any quadratic residue. If you can do this, then you can factor. For details, consult [1570,1571,35,36]. 23.16 Quantum Cryptography
Quantum cryptography taps the natural uncertainty of the quantum world. With it, you can create a communications channel where it is impossible to eavesdrop without disturbing the transmission. The laws of physics secure this quantum channel: even if...
View Full Document
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