CS60065: Cryptography and Network Security [L-T-P: 3-1-0]

Course Objectives


This course introduces the basics of modern cryptography and some related, basic aspects of network security. In terms of topics, we will largely study cryptographic tools for ensuring message confidentiality, integrity and user authentication. If time permits, we will also cover some advanced cryptography, e.g., post-quantum secure cryptosystems and some general tools that allow building privacy preserving or enhancing computation. The course will be mathematical in nature.

Pre-requisites


The course has some formal prerequisites. So it would greatly benefit to brush up the topics listed below.

[For Cryptography]: Discrete Structures, Basics of Algorithm Design and Analysis, and Linear Algebra.
[For Network security]: Basic idea of Computer Networks.

We will also cover some new (& may briefly recap some existing) mathematical tools useful in cryptographic contexts.

Course Logistics


Where and When?

  1. Wednesday: 12:00 - 12:55 PM (Lec/Tut)
  2. Thursday: 11:00 - 11:55 AM (Lec)
  3. Friday: 9:00 - 10:55 AM (Lec)

Exams

Teaching Assistants

Requirements

  1. Teacher's Assessment [30%]
    • Class Attendance + Tutorials
    • Short Class Test(s) + Presentation (PTN)
  2. Mid semester exam [30%]
  3. End semester exam [40%]



[NOTE]: We will post several details frequently throughout the course. Keep an eye on this webpage for the latest updates.




Other Instructions & Policies


Tutorials may be interactive, where students will be asked to demonstrate solutions to problems during the sessions. There will also be presentation sessions carrying marks. Depending on class strength, each (or a small group of) student(s) will be asked to present a topic related to, but uncovered in the syllabus. Getting caught in any kind of malpractice during tests, exams or tutorials will result in failing the course.

Resources


We will mostly follow the texts mentioned below. Slides (& any other extra material) used in classes will be shared here in time. Any extra material, that we may use, will be shared on this webpage in time.

  1. Cryptography: Theory and Practice (By Douglas R. Stinson, Maura B. Patterson) [Textbook 1]
  2. Understanding Cryptography: A Textbook for Students and Practitioners (By Christof Paar, Jan Pelzl, Tim Güneysu) [Textbook 2]
  3. Introduction to Modern Cryptography (By Jonathan Katz, Yehuda Lindell) [Reference]
  4. The Joy of Cryptography (By Mike Rosulek) [Reference]
  5. Handbook of Applied Cryptography (By Alfred J. Menezes, Paul C. van Oorschot, Scott A. Vanstone) [Reference]
  6. Cryptography and Network Security (By William Stallings) [Reference]
  7. Computer Security (By David Wagner, Nicholas Weaver, Peyrin Kao, Fuzail Shakir, Andrew Law, Nicholas Ngai) [Reference]

Syllabus/Timeline/Tests/Tutorials


To be updated as the course proceeds.


Topic Reference Week Tutorials/Class tests
1. Logistics, Introduction
& Course Overview
[1], [6], WWW 1 --
2. Secret Key Encryption [1], [3] (Sec - 1.2, 1.4.1) 2 --
3. Math basics (part-1)
+ Classical Ciphers
[1], [5], [6] 3 --
4. Math basics (part-2) +
Perfect Secrecy + Entropy
[1], [3] (Sec 2)
Extra lecture notes: Here, Here
3, 4 --
5.1 Block Ciphers - Part 1
SPN and Feistel Networks
Attacks on SPN: LC, DC
[1], [2], [5] 4, 5, 6 Tutorial 1: Week 5
Classical Ciphers, SKE
Math Basics, Perfect Secrecy
5.2 Block Ciphers - Part 2
DES and Extensions
Math basics (part-3) & AES
Modes of Operations
[1], [2], [5] 6, 7 Tutorial 2: Week 7
SPN and Feistel Networks,
Block ciphers, Groups, Rings
and Galois Field Arithmetic
6.1 Cryptographic Hash Functions
Iterated Hash Functions, SHA-2
Merkle-Damgård Paradigm
[1], [2] 8, 9 Class-test 1: 04/09/25.
Syllabus: Topics 1-5
6.2 Sponge Paradigm: SHA-3, Keccak
Message Authentication Codes
Authenticated Encryption
[1], [2] 9 Tutorial 3: Week 9
Hash Functions & MACs
Mid-Sem Examination
Autumn break
-- 10, 11 Date: 22/09/2025
Venue: CSE 120, Time: 2-4 pm
Autumn break for students -- 12 Autumn break for students
7.1 Public Key Encryption - Part 1
Math basics (part-4)
RSA Encryption, Primality testing
Factoring algorithms. Attacks on RSA.
[1], [2] 13, 14, 15 Presentations
Groups 1 - 6
7.2 Public-Key Encryption - Part 2
Discrete Logarithm Problem (DLP)
ElGamal Encryption
Classical algorithms to solve DLP
Diffie-Hellman Key Exchange
Diffie-Hellman Problems
Elliptic Curve (EC) Cryptography
Glimpse into Functional Encryption
(Last topic is out of syllabus)
[1], [2], [3] 15 --
8. Digital Signature Schemes
Role in Blockchains (briefly)
RSA, ElGamal signatures, Attacks
Schnorr, (EC)DSA signatures
Bilinear pairings on EC groups
BLS signatures, 3-Party DHKE
(Last 3 topics are out of syllabus)
[1], [2] 16 Class-test 2: 06/11/25.
Syllabus: Topics 7-8
9. Basics of Key Management,
Certificates and PKI
Overview of TLS Protocol
[2], [6], [7] 16, 17 Presentations
Groups 7 - 10
10. Quantum-safe Cryptography:
Informal introduction to Lattices
& lattice-based Cryptography
Reference slides:
Here, Here
17 (Topics are out of syllabus)