DATA COMPRESSION AND ENCRYPTION (DCE) DECEMBER 2010 [ELECTIVE] ELECTRONICS AND TELECOMMUNICATION SEMESTER 7

DATA COMPRESSION AND ENCRYPTION (DCE) DECEMBER 2010  [ELECTIVE] ELECTRONICS AND TELECOMMUNICATION SEMESTER 7

Con.5656-10.                                     (REVISED COURSE)                        GT-8910

                                                                     (3 Hours)                         [Total Marks:-100]

N.B: (1) Question No.1 is compulsory.
        (2) Attempt any four question out of remaining six questions.
        (3) Assume suitable data wherever required. 
        (4) Figures to the right indicate full marks.

1. (a) What are the different measures of performance of data compression
          techniques? [5 Marks]
    (b) Discuss the drawbacks of statistical methods. [5 Marks]
    (c) What is motion compression w.r.t Image Compression. [5 Marks]
    (d) Discuss secure electronic payment system. [5 Marks]

2. (a) Distinguish between Scalar and Vector Quantization. Discuss the MPEG Audio Encoder
         and Decoder systems. [10 Marks]
    (b) Describe the features of Video Compression as compared to Image Compression. Explain
          MPEG industry standard for Video Compression. [10 Marks]

3. (a) A source Emmits Letter's from alphabet A= {m, n, o, p, q} with probabilities p(m) = p(n) =
         0.2, p(o) = 0.4, p(p) = p(q) = 0.1. [10 Marks]
           (i) Calculate the entropy of the source.
          (ii) Find Huffman Code using both the standard procedure and minimum variance method.
         (iii) Find the average length of code and redundancy for each of the code of part (II).
    (b) What are the different types of DES prevalent today? How is the security aspect maintained
           in DES? [10 Marks]

4. (a) In which situation LZ 77 does the perform 'best' ? 'Worst'? Encode the string 'mnop mnopponm'
         using LZ 78. What are the limitations of this method? [10 Marks] 
    (b) What are the main features of Digital Signature Standards. Suggest a suitable scheme for
           secure communication between 'A' user and 'B' user covering issue of confidentiality and                                authentication. Justify your choice. [10 Marks]

5. (a) In high fidelity digital recording with a maximum frequency of 20 KHZ. The sampling rate
         equals 44.1 KHz. How much memory is needed to store 1 hours of music if the number of
         quantization level is:- [10 Marks]
        
    (b) Explain the JPEG compression method used for Image Compression. How JPEG-LS is
         different from JPEG? [10 Marks]  

6. (a) What are the Active and Passive attacks on security of a system? How Chinese Remainder
          Theorem use in security? [10 Marks]
    (b) Discuss the certificate based and Bio-metric authentication. How does massage authentication
         is different from the above. [10 Marks]

7. Write short note on(any two):- [20 Marks]
      (a) "Frequency masking" and "Temporal Masking" w.r.t Audio Compression.
      (b) "S" Box Design
      (c) Diffie-e-Hellman Key Exchange
      (d) Fire wall design