Tutorial3_jul10 - Tutorial 3 ICT 211 Question 1 Describe...

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Tutorial 3 – ICT 211 Question 1 Describe four different approaches to message authenticity without using PKS. Suppose you need to provide only authenticity protection in a network. Suppose further that performing encryption is very much more time consuming than computing checksum, MAC or hash. Explain which of these approaches is likely to be the least suitable if efficiency is a main concern in your network. Is this approach still more appropriate that one using PKS? Explain your answer. Question 2 (a) Suppose you just used one key and the message sent comes with a time stamp, a sequence and a checksum as follows: Actual Data Timestamp Sequence Number Checksum The entire packet is encrypted. Are there any key management issues in this case? Explain your answer. Does this provide any form or certain degree of authenticity protection? Also explain your answer. Question 3 (a) Suppose you have a network of n users. Suppose each pair of users need to have secure channel of communication of communication that others could not listen in. (i)
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This note was uploaded on 09/06/2010 for the course IT ICt211 taught by Professor Tan during the Spring '10 term at Singapore Institute of Management.

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Tutorial3_jul10 - Tutorial 3 ICT 211 Question 1 Describe...

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