1 T215B: Communication and information technologies (II) ______________________________________________________________________________ Tutor-Marked Assignment _____________________________________________________________________________ Cut-off date: 2 M

1
T215B: Communication and information technologies (II)
______________________________________________________________________________
Tutor-Marked Assignment
_____________________________________________________________________________
Cut-off date: 2 May, 2016
_____________________________________________________________________________
Total Marks: 100
TMA Contents
Question 1 (30 marks)
Question 2 (45 marks)
Question 3 (25 marks)
Plagiarism Warning:
As per AOU rules and regulations, all students are required to submit their own TMA work and avoid plagiarism. The AOU has implemented sophisticated techniques for plagiarism detection. You must provide all references in case you use and quote another person's work in your TMA. You will be penalized for any act of plagiarism as per the AOU's rules and regulations.
Declaration of No Plagiarism by Student (to be signed and submitted by student with TMA work):
I hereby declare that this submitted TMA work is a result of my own efforts and I have not plagiarized any other person's work. I have provided all references of information that I have used and quoted in my TMA work.
Name of Student:………………………………..
Signature:…………………………………………...
Date:……………………………………………………
2
Question 1: Network security
This question carries 30% of the marks for this assignment.
During your study of T215B, you have been introduced to a set of concepts, protocols and threats to network security. Based on this information as well as the internet and other resources (e.g., books and AOU e-library), write a short report explaining the following factors:
 Overview of the IPsec protocol.(6 marks)
 Comparison between Caesar cipher using diagraph coding and Vigenère Cipher in terms of their operation and level of security (6 marks).
 Description of Message Digest Algorithm 5 (MD5). (6 marks)
 Explanation for the two different approaches for doing Block encryption with stating their features and drawbacks for each approach. (6 marks)
Short Report Writing:
Please adhere to the following guidelines for writing your report:
Your report should be between 500 and 600 words in length. Under-length and over-length reports will be penalized.
Your report should include at least two figures and/or tables. Do not forget to include a caption for each figure/table and to use cross-referencing. (2 Marks)
Ensure that your report has an appropriate structure and style. (2 marks)
You must cite all the references i.e. any internet web site, book, journal, article etc. that you have used as a source of information for your report (2 marks)
You are advised to remind yourself of the issues concerning plagiarism.
Question 2: Double Encryption
This question carries 45% of the marks for this assignment.
BOB wants to send a secure message to Alice. He doesn’t want Eve to read it. He decided to apply double encryption scheme to achieve this task. This double encryption scheme consists of two-stage cascaded encryption processes as shown in the figure below:
Key Keyword
Plain text intermediate code Cipher text
P code 1 C
Stage 1: Caesar cipher with single coding
Stage 2: Vigenère cipher coding
3
Knowing that:
- The encryption key for Caesar cipher is 15.
- The keyword for Vigenère cipher is: “secret”.
- The original message is: “transfer million dollar”.
What will be the final encrypted message? Show your work in details including the two stages encryption processes in the form of a composite table.
Note: Table below help you to find the code equivalent to each letter.
Question 3: Basics of Microphones
This question carries 25% of the marks for this assignment.
You have studied in T215B Microphones. In your own words, write a summary about microphones where by you briefly answer the following questions:
 What is a microphone?
 What are the various types of microphones?
 What are the various usages for different types of microphones?
 List the advantages/disadvantages for the various types of the microphones?
This summary aims to explain the importance of various types of microphones to intermediate level reader.
The specification for the summary is as follows:
 the number of words must be between 300 and 400 inclusive,
 there must be at least two sections,
 The sections should use an appropriate mixture of descriptions, explanations, and examples.
 Bearing in mind the audience level and purpose.
 You should include the reference(s) of your answer in a standard format.
4
Criteria for marking
The criteria to be considered in marking:
1. general description of the microphone (2 Marks)
2. Various types of microphones (5 Marks)
3. Various usages of microphones. (6 Marks)
4. advantages/ disadvantages of microphones (6 Marks)
5. Is the structure and style appropriate for the audience, purpose and medium? (2 Marks)
6. Is the English correct? (2 Marks)
7. Citation and references in standard format. (2 Marks)
***************************
End of TMA questions