Courses » Cryptography and Network Security

Cryptography and Network Security

About the course
The aim of this course is to introduce the student to the areas of cryptography and cryptanalysis. This course develops a basic understanding of the algorithms used to protect users online and to understand some of the design choices  behind these algorithms. Our aim is to develop a workable knowledge of the mathematics used in cryptology in this course. The course emphasizes to give a basic understanding of previous attacks on cryptosystems with the aim of preventing future attacks.

Industry support – list of companies/industry that will recognize/value this online course

IT companies, DRDO, ISRO, NEVY.

12791 students has enrolled already!!

Course instructor

Sourav Mukhopadhyay is an Associate Professor, Department of Mathematics at Indian Institute of Technology Kharagpur. He has completed his B.Sc (Honours in Mathematics) in1997 from University of Calcutta, India. He has done M.Stat (in statistics) and M.Tech (in computer science) from Indian Statistical Institute, India, in 1999 and 2001 respectively. He worked with Cryptology Research Group at Indian Statistical Institute as a PhD student and received his Ph.D. degree in Computer Science from there in 2007. He was a Research Assistant at the Computer Science department of School of Computing, National University of Singapore (NUS). He visited Inria Rocquencourt, project CODES, France and worked as a post-doctoral research fellows at the School of Computer Engineering, Nanyang Technological University (NTU), Singapore. He was a post-doctoral research fellows and a part time Lecturer with School of Electronic Engineering, Dublin City University (DCU), Ireland.

 Course layout

Week 1:
Introduction to cryptography, Classical Cryptosystem, Cryptanalysis on Substitution Cipher (Frequency Analysis), Play fair Cipher, Block Cipher.
Week 2: Data Encryption Standard (DES), DES (Contd.), Triple DES, Modes of Operation, Stream Cipher, Pseudorandom Sequence.
Week 3: LFSR based Stream Cipher, Mathematical background, Abstract algebra, Number Theory.
Week 4:Modular Inverse, Extended Euclid Algorithm, Fermat's Little Theorem, Eular Phi-Function, Eular's theorem, Quadratic Residue, Polynomial  Arithmetic.
Week 5: Advanced Encryption Standard (AES), Introduction to Public Key Cryptosystem, Diffie-Hellman Key Exchange, Knapsack Cryptosystem, RSA Cryptosystem.
Week 6: More on RSA, Primarily Testing, ElGamal Cryptosystem, Elliptic Curve over the Reals, Elliptic curve Modulo a Prime.
Week 7: Generalised ElGamal Public Key Cryptosystem, Chinese Remainder Theorem, Rabin Cryptosystem, Legendre and Jacobi Symbol.
Week 8: Message Authentication, Digital Signature, Key Management, Key Exchange, Hash Function.
Week 9: Universal Hashing, Cryptographic Hash Function, Secure Hash Algorithm (SHA), Digital Signature Standard (DSS), More on Key Exchange Protocol.   
Week 10: Cryptanalysis, Time-Memory Trade-off Attack, Differential Cryptanalysis, More on Differential Cryptanalysis, Linear Cryptanalysis.
Week 11: Cryptanalysis on Stream Cipher, Algebraic Attack, Implementation Attacks, side channel attack.
Week 12: Internetwork Security, SSL, PGP, Cloud Security, Introduction to Blockchain and Bitcoin.

Certification exam:

1. The exam is optional for a fee.
2. Date and Time of Exams: April 28 (Saturday) and April 29 (Sunday) :  Afternoon session: 2pm to 5pm.
3. Registration url: Announcements will be made when the registration form is open for registrations.
4. The online registration form has to be filled and the certification exam fee needs to be paid. More details will be made available when the exam registration form is published.


• Final score will be calculated as : 25% assignment score + 75% final exam score.
• 25% assignment score is calculated as 25% of average of 8 weeks course: Best 8 out of 12 assignments.
• E-Certificate will be given to those who register and write the exam and score greater than or equal to 40% final score. Certificate will have your name, photograph and the score in the final exam with the breakup. It will have the logos of NPTEL and IIT KHARAGPUR. It will be e-verifiable at nptel.ac.in/noc.