Answer Happy

1. Basic Understanding (10 Points total; 2 points each). For each statement below, please evaluate its correctness based on what we have learned in ECE422/553. Put T inside () if you think it is a true statement; otherwise put F. 1) For Nusers, a linear number of public-private key pairs is need to be established and distributed to allow pairwise confidential communication between any two users; instead, symmetric encryption requires a quadratic number of secret keys. () 2) Message integrity means that the message is known only to the sender and intended receiver. Message confidentiality means that message has not been altered. ( ) 3) The purpose of the random nonce in the end authentication is to defend against the replay attack. () 4) In CSMA/CD, after the fifth collision, the probability that a nodes chooses K=10 is 10/32 ( ) 5) Both switch and router use store-and-forward ( )