Register Number

QP. CODE: 2
AAA COLLEGE OF ENGINEERING AND TECHNOLOGY
Amathur, Sivakasi – 626 005.
INTERNAL TEST – I
CCS354 –NETWORK SECURITY
DEPARTMENT OF ARTIFICIAL INTELLIGENCE AND DATA
SCIENCE
Date & Session: 12.03.2025&AN Year / Semester: III/V Max. Marks:100
Name of the Course Instructor: Dr.P. Deva Balan, Prof/HOD/AI&DS
COURSE OUTCOMES:
At the end of the course the students will be able to
CO Course outcomes BTL
Level
CO-1 Interviewing the basic layers and its functions of networks. RE
CO-2 Apply the concept of data flows between nodes. AP
CO-3 Develop algorithms for routing. CR
CO-4 Develop protocols for various network functions. CR
CO-5 Explore how various application layer protocols function AP

COURSE ASSESSMENT MATRIX

PO PO PO PO PO PO PO PO PO PO PO PO1 PSO PSO PSO
CO
1 2 3 4 5 6 7 8 9 10 11 2 1 2 3
CO1 3 3 2 2 2 - - - 2 1 2 1 2 3 1
CO2 1 1 3 2 2 - - - 2 2 1 1 3 1 2
CO3 1 2 1 1 2 - - - 3 3 1 3 2 1 3
Answer ALL questions
Part A 10 x 2 = 20 Marks
1) What is a hash in cryptography? RE, CO1
2) What is a digital signature? RE, CO1
3) List the two approaches of digital signatures. RE, CO1
4) How is the MAC function security expressed? UN, CO2
5) List the four requirements defined by Kerberos. RE, CO2
6) What is a realm in Kerberos? RE, CO2
7) Define an SSL session. RE, CO3
8) Define TSL? RE, CO3
9) Define the Extensible Authentication Protocol. RE, CO3
10) UN, CO3
Difference between TSL and SSL?
Part B 5 x 13 = 65 Marks
11 a) Explain the RSA operation. UN, CO1
(OR)
11 b) Discuss in detail the Advanced Encryption Standard (AES) with neat
UN, CO1
diagrams.
12 a) Explain the steps involved in the Digital Signature Algorithm (DSA) with
UN, CO1
examples.
(OR)
12 b) Explain the public-key cryptosystems with neat diagrams. UN, CO1
13 a) Explain the role of X.509 certificates and Public-Key-Infrastructure (PKI) UN, CO2
in key management. Discuss the advantages and potential
 vulnerabilities of PKI
(OR)
13 b) Explain the PKI management model and its operations with the help of a
UN, CO2
diagram.
14 a) Explain the symmetric key distribution using asymmetric encryption. UN, CO2
(OR)
14 b) With neat diagrams, explain the secret key distribution with
UN, CO2
confidentiality and authentication.

15 a) Explain Kerberos as a Key Distribution Center (KDC) and an

UN, CO3
authentication protocol.
(OR)
15 b) Explain Tickets and Ticket-Granting Tickets in detail UN, CO3
Part C 1 x 15 = 15 Marks
16 a)i A company needs to secure a database of employee salaries. They are
considering using a block cipher with either ECB or CBC mode. Given
that many employees have the same salary, which mode of operation AP, CO1
would you recommend and why? What would be the security
implications of choosing the other mode?
a)ii A cybersecurity team discovers that the private key of a major
Certificate Authority (CA) has been stolen by hackers. Explain what this
means for the security of digital certificates issued by that CA. What AP, CO2
immediate actions must the CA take within the PKI model to mitigate
the damage and what impact would this have on millions of websites
and their users?
(OR)
16 b)i A company's web server has a valid X.509 certificate. A user's web
browser receives this certificate but displays a security warning that
the certificate's validity period has expired. Explain the security risk
UN, CO2
this poses to the user and what practical steps the user should take.
What element of the X.509 certificate would the browser specifically
check to determine this issue?
b)ii An online file storage service uses SHA-256 to ensure the integrity of
uploaded files. A user uploads a large video file and receives a message
digest (hash) from the service.
i. A hacker manages to replace a few seconds of the video file AP, CO1
on the server. When a second user downloads the file and
computes the hash, what would they observe, and why is the
SHA algorithm effective in this scenario?

CO RE UN AP AN CR Total
CO1 6 26 8 40
CO2 4 28 7 39
CO3 6 15 21
Total 16 69 15 100