STUPIDSID
Answer in brief any four Q.1(a,b,c,d,e)
1(a)
Explain different redundancies in data and how they are used for data compression. Also give evaluation parameters for compression techniques.
5 M
1(b)
What are the goals of cryptographic system? Describe various attacks compromising these goals.
5 M
1(c)
State Fermat's Little Theprem, Eulet's Theorem in modular arithmetic. What is Euler's Totient function? Compute φ(37),
φ(35) and φ(75).
φ(35) and φ(75).
5 M
1(d)
Give an example of each:
Substitution cipher
Transposition cipher
Stream cipher
Block cipher
Substitution cipher
Transposition cipher
Stream cipher
Block cipher
5 M
2(a)
Explain the principle of arithmetic coding. Hence generate a decimal tag for the sequence : SWISS_MISS. Also decode the decimal tag.
10 M
2(b)
What are the advantages of minimum variance. Hutiman codes over normal Huffman codes? Design a minimum variance Huffman code on the source with alphabet A={a1,
a2,
a3,
a4,
a5} with respective probabilities {0.25,
0.2,
0.15,
0.3,
0.1}.
a2,
a3,
a4,
a5} with respective probabilities {0.25,
0.2,
0.15,
0.3,
0.1}.
10 M
3(a)
Explain lossy and lossless schemes for image compression. Give and overview of JPEG-2000.
10 M
3(b)
Explain Frequency masking. Temporal masking with respect to audio compression. Also explain how an MP-III encoder works.
10 M
4(a)
Compute the encrypted and decrypted text using RSA algorithm for the plaintext 88. Public key is (n,
e) =(187,
7).
e) =(187,
7).
10 M
4(b)
Perform LZ-78 compression on the following string and find the compression ratio. 10001111010111100011111100011111
10 M
5(a)
Explain Triple-DES with two keys and the "Meet-in-the-middle-attack".
10 M
5(b)
Consider a Diffie-Hellman scheme with a common prime q=11 and a primitive root α=2.
i) Show that 2 is primtive root of 11.
ii) If use A has public key YA=9, what is A's private-key XA?
iii) If user B has public key Ya=3, what is the shared secret key K?
i) Show that 2 is primtive root of 11.
ii) If use A has public key YA=9, what is A's private-key XA?
iii) If user B has public key Ya=3, what is the shared secret key K?
10 M
Write a short note any four Q6.(a,b,c,d,e)
6(a)
Digital Signatures
5 M
6(b)
H264. Video coding standard
5 M
6(c)
Ethical Hacking
5 M
6(d)
Digital Immune Systems
5 M
6(e)
Elliptic curves for cryptography
5 M
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