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Unformatted text preview: CIS 4360 Introduction to Computer Security Home Assignment 4, Fall 2011 WITH ANSWERS This concerns the basic requirements for Authentication and Cryptography. 1. Passwords are entered by users and checked by computers. Thus there has to be some com- munication channel between user and computer. So far we have taken an abstract view of this channel and assumed that it exists and that it is adequately secure. When is this assumption justified? When is it unjustified? Answer: The channel between the user and computer could be an unprotected wireless chan- nel, a public telephone lines, the Internet, etc. A protected channel could be a wire between a terminal and a computer (depends on circumstances), a cryptographically protected channel between two devices, a trusted path on a computer. So the assumption is justified when the communication channel is protected, while it is unjustified when the communication channel is unprotected....
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This document was uploaded on 12/04/2011.
- Fall '09
- Computer Security