CY-503-B Network Security - Nov 2023 Question Paper

Under each question, How to answer lists the points an answer should cover, outlined by CampusPrep from the syllabus. Check the details against your textbook.

1. 7 Marks
   aSummarize the public key cryptographic principles. Explain RSA algorithm for given example, where $p = 3$ and $q = 11$.
   How to answer

   • Public-key principles: key pair, trapdoor one-way function, confidentiality, authentication, key distribution
   • RSA key generation steps: n=p*q, phi(n), choose e, compute d
   • Apply p=3, q=11: n=33, phi=20, e.g. e=3, d=7 with encryption/decryption formulas
   • Example encryption/decryption of sample message number
2. 7 Marks
   bExplain with an example how encryption and decryption is performed in AES?
   How to answer

   • AES overview: block size 128-bit, key sizes, rounds
   • Encryption steps: SubBytes, ShiftRows, MixColumns, AddRoundKey with example
   • Decryption as inverse transformations in reverse order
   • Key expansion and example walkthrough
3. 7 Marks
   aDescribe the steps to find the message digest using SHA-512 algorithm. What is the order of finding the messages which have the same message digest?
   How to answer

   • SHA-512 padding, parsing, initial hash values
   • 80 rounds compression function with message schedule
   • Final 512-bit digest output
   • Birthday attack and order 2^(n/2) for same digest / collision
4. 7 Marks
   bDiscuss in detail Biometric Authentication.
   How to answer

   • Definition and need for biometric authentication
   • Types: fingerprint, iris, face, voice
   • Enrollment vs verification/identification phases
   • Advantages, limitations and security issues
5. 7 Marks
   aWith a neat sketch explain the general format of the PGP message.
   How to answer

   • PGP services: confidentiality, authentication, compression
   • General message format components: session key, signature, compression
   • Neat sketch showing order of operations
   • Example flow of PGP message creation/reception
6. 7 Marks
   bExplain the transport and Tunnel model operations for AH in IP Security.
   How to answer

   • IPSec AH purpose and header
   • Transport mode operation for AH
   • Tunnel mode operation for AH
   • Comparison of protection scope in two modes
7. 7 Marks
   aDefine Intrusion. Discuss Network based Intrusion detection system with a neat sketch.
   How to answer

   • Definition of intrusion and intruder types
   • NIDS architecture components: sensors, analyzer, alert
   • Neat sketch of NIDS placement in network
   • Detection methods: signature vs anomaly
8. 7 Marks
   bWrite the classification of firewalls. Explain Packet filtering firewalls.
   How to answer

   • Firewall classification basis
   • Types: packet filtering, stateful, application, circuit
   • Packet filtering rules, ACLs and working
   • Advantages and limitations
9. 7 Marks
   aExplain in detail the types of malicious software.
   How to answer

   • Definition of malware
   • Types: virus, worm, trojan, spyware, ransomware, etc.
   • Propagation and payload characteristics
   • Examples and countermeasures
10. 7 Marks
    bWrite about the security issues in WTLS.
    How to answer

    • WTLS overview in WAP stack
    • Handshake, record layer security issues
    • Gap in WAP gateway, datagram issues
    • Mitigations
11. 7 Marks
    aExplain about Wireless Application Protocol security.
    How to answer

    • WAP need and security goals
    • WAP security layers: WTLS, WML
    • End-to-end security problem at gateway
    • Features and limitations
12. 7 Marks
    bExplain the WAP architecture with an example.
    How to answer

    • WAP architecture components: client, gateway, origin server
    • Protocol stack layers
    • Example transaction flow with diagram
    • Role of WAP gateway in translation
13. 7 Marks
    aDefine SSL. What are the different services provided by SSL Record Protocol?
    How to answer

    • SSL definition and purpose
    • SSL Record Protocol operation: fragmentation, compression, MAC, encryption
    • Services: confidentiality, integrity, authentication
    • Header format
14. 7 Marks
    bExplain the application of Secure Electronic Transaction in the Business Environment.
    How to answer

    • SET purpose for e-commerce
    • Participants: cardholder, merchant, banks
    • Dual signature and transaction flow
    • Business benefits and security
15. 14 Marks
    Write short notes on any two of the following:

    1. a)Cipher block modes of operation.
    2. b)Trusted Operating system.
    3. c)Circuit-level gateway firewalls and application-level gateway firewalls.
    4. d)Security considerations and threats.
    How to answer

    • Select any two topics for short notes
    • Key definitions and working principles for each
    • Diagrams/examples where relevant
    • Advantages, uses and limitations