This preview shows pages 1–2. Sign up to view the full content.
This preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
Unformatted text preview: Computer Science and Engineering, UCSD Spring 11 CSE 207: Modern Cryptography Instructor: Mihir Bellare Problem Set 2 April 6, 2010 Problem Set 2 Due: Wednesday April 13, 2010, in class. Problem 1. [20 points] Define the family of functions F : { , 1 } 128 { , 1 } 128 { , 1 } 128 by F ( K,M ) = AES ( M,K ). Assuming AES is a secure PRF, is F a secure PRF? If so, explain why. If not, present the best attack (with analysis) that you can. Problem 2. [60 points] Let F : { , 1 } k { , 1 } l { , 1 } L be a family of functions where l,L 128. Consider the game G of Fig. 1. We define Adv lr F ( B ) = 2 Pr bracketleftBig G B true bracketrightBig 1 . Let ( x 1 ,x 1 1 ) ,... , ( x q ,x q 1 ) be the queries that B makes to its oracle. (Each query is a pair of lbit strings, and there are q queries in all.) We say that B is legitimate if x 1 ,... ,x q are all distinct, and also x 1 1 ,... ,x q 1 are all distinct. We say that F is LRsecure if Adv lr F ( B ) is small for every...
View
Full
Document
This note was uploaded on 08/31/2011 for the course CSE 207 taught by Professor Daniele during the Winter '08 term at UCSD.
 Winter '08
 daniele
 Computer Science

Click to edit the document details