# 2003 Andhra University MSc Computer Science Cryptography Question paper

** University Question Papers **

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**2003 Andhra University MSc Computer Science Cryptography Question paper

M.Sc. DEGREE EXAMINATION 31 Oct 2003

Second Year - Third Semester Computer Science

Elective - Cryptography

Time: Three hours

Maximum: 75 marks

First question is compulsory.

Answer any FOUR from the remaining questions.

All questions carry equal marks.

Write all bits of the first question at one place.

1.

a. What is encryption?

b. What is decryption?

c. What is web?

d. What is Non-repudiation?

e. What is public key?

f. What is private key?

2. Describe Mono alphabetic substitution methods.

3. Describe modern encryption techniques DES and Triple DES

4. What are digital signatures and explain the approaches for digital signatures based on public key encryption

5. Describe confidentiality using conventional encryption

6. Describe Block cipher modes of operation

7. Describe authentication protocols and applications

8. Write short notes on the following: a. MAC algorithm

b. RSA algorithm