Engineering BE Computer Engineering Sem 7 December 2019 2019 Cryptography And System Security Question Paper - Mumbai University | munotes

Questions asked in this paper

1. Q1 Solve any four: (5 marks for each)
   • (a) Why is padding done in MDS and SHA? 05
   • (b) What are the properties of cryptographic hash functions? 05
   • (c) Explain with examples, poly-alphabetic & mono-alphabetic ciphers. 05
   • (d) What are the different types of viruses? Explain in brief. 05
   • (e) With examples explain Denial of service attack. OS
2. Q2 (a) Justify why DES is a fiestel cipher. Explain the different operations in DES. How are the subkeys generated in each round different from each other? 12 marks
   • (b) Design a double transposition cipher and use it to. encrypt “Enemy attacks tonight”, 08 Column Key to be used is [5,2,4,3,1]
3. Q3 (a) What is a digital certificate? Explain the significance of X.509 certificate in PKI. How is a digital certificate verified by the receiver during a communication? 10 marks
4. Q3 (b) How is single sign-on achieved in Kerberos? What is the role of each server in 10 marks
5. Q4 (a) AandB use RSA to communicate securely. B choses public key (e,n) as (7,221). Calculate p,q and On. Compute the private key, d. A choses public key as (Ea,Na). A wishes to send message m=5 to B such that confidentiality is maintained With what key will A encrypt the message? 10 marks
6. Q4 (b) What is session hijacking? What are the different ways to prevent session 10 marks
7. Q5 (a) What are the different types of firewalls? Differentiate between working of the statefull and stateless inspection firewalls 10 marks
8. Q5 (b) Discuss how authentication and integrity is achieved in SET payment protocol? 10 marks
9. Q6 (a) in brief about (any two): 10 marks
   • i) Database Security li) Key generation in IDEA
10. Q6 (b) How does the protocol help in achieving authentication and integrity? 10 marks

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