Information Theory and Coding - Dec 2014

Information Technology (Semester 4)

TOTAL MARKS: 80
TOTAL TIME: 3 HOURS (1) Question 1 is compulsory.
(2) Attempt any three from the remaining questions.
(3) Assume data if required.
(4) Figures to the right indicate full marks. 1 (a) Define Chinese Remainder Theorem and its application(5 marks) 1 (b) Explain Term Entropy in Information Theory and its significance.(5 marks) 1 (c) Describe Fermat's Little Theorem. And its application(5 marks) 1 (d) Explain Cyclic Codes.(5 marks) 2 (a) Explain Adaptive Huffman encoding techniques. Encode the data pattern "accabbcdaa" using Above technique.(10 marks) 2 (b) Compare Symmetric and Asymmetric Cryptography(5 marks) 2 (c) Explain various Security Goals.(5 marks) 3 (a) Explain convolution code in brief.(10 marks) 3 (b) Consider the source probabilities
{0.20, 0.20, 0.15, 0.15, 0.10, 0.10, 0.05, 0.05}
i) Determine the efficient fixed length code for the source.
ii) Determine Huffman code for this source
iii) Compare the two codes and comment.(10 marks) 4 (a) Explain DES and give an outline of the algorithm.(10 marks) 4 (b) Which of the following g(x) values guarantees that a single bit error is caught? In each case, what is the error that cannot be caught?
i) x+1 ii) x³(10 marks) 5 (a) Describe with example Modular Arithmetic, Exponentiation and Congruences.(10 marks) 5 (b) Define:-
i) Hamming Weight
ii) Hamming Distance
iii) Syndrome
iv) Linear Code Properties
v) Code Rate(10 marks)

Write short notes on:

6 (a) RSA(5 marks) 6 (b) RLE(5 marks) 6 (c) Speech Compression(5 marks) 6 (d) Random Number Generation(5 marks)