COMP 4140 Introduction to Cryptography and Cryptosystems





04/12: Lecture 30 is now available.


TAís email address:




o   Instructor: Noman Mohammed

o   Email: (Please mention COMP 4140 in the subject)

o   Office location: EITC E2-417

o   Lecture time and location: M/W/F 9:30 AM -10:20 AM in EITC E2-125

o   Office hours: M/W/F 10:30 AM -11:30 AM, or by appointment

o  TA: Md Toufique Morshed Tamal <>


Course Description


o   Description and analysis of cryptographic methods used in the authentication and protection of data. Classical cryptosystems and cryptanalysis, symmetric cryptosystems, and asymmetric (or public-key) cryptosystems.




o   COMP 2130 (Discrete Mathematics for Computer Science), Students must be registered in fourth year of a Major or Honours programme in the Department of Computer Science COMP 2140 (or 074.214) (C) and COMP 2160 (or 074.216) (C) and COMP 2130 (C).


Textbook and Other Readings


o   Required Textbook

o   Christof Paar and Jan Pelzl. Understanding Cryptography. Springer, 2010.


o   Recommended optional textbooks:

o   Jonathan Katz and Yehuda Lindell. Introduction to Modern Cryptography. CRC Press, 2007.

o   Niels Ferguson, Bruce Schneier, and Tadayoshi Kohno. Cryptography Engineering. Wiley, 2010.

o   D.R. Stinson. Cryptography- Theory and Practice, Third Edition, Chapman and Hall/CRC Boca Raton, 2006.

o   Network Security: Private Communication in a Public World, by Charlie Kaufman, Radia Perlman, and Mike Speciner. Prentice Hall, 2nd edition 2002.




o   Assignments: 40%

o   Midterm exam: 20% (tentative date: sometime in the last two weeks of October)

o   Final exam: 40%


o   The final grade is based on curving the overall performance. There is no direct mapping between numerical percentage grades and final letter grades for this course. 



Administrative Policy


o   There will be 4 assignments: 2 before the midterm and 2 after the midterm. All the assignments will be due in class (unless otherwise specified). Late submissions suffer a penalty rate of 20% per day, up to 5 days (weekends count).

o   The midterm and final are closed-book exams. The midterm covers all material presented up to that point in the course. The final exam covers material from the whole term, with emphasis on the second half of the course. Detailed information about the midterm will be released at a later time.

o   There is no makeup to a missing midterm, so make sure that you write the midterm at the scheduled time. In the case of a serious illness or emergency, the weight of the midterm will be moved towards the final exam.

o   Final exam make-up is possible ONLY under a university-approved condition, such as sickness with a doctor's note. Be prepared to provide written documentation (e.g., a medical excuse from your doctor) to verify the emergency and its seriousness.

o   Students are expected to attend every class. Some material may only be covered in class and not made available on the course note/website. Students are expected to read the assigned materials and to actively participate in class discussions.

o   In the event of extraordinary circumstances beyond the University's control, the content and/or evaluation scheme in this course is subject to change.











Sep 8

Course Logistics and Overview

o   Section 1.1: Overview of Cryptography

o   Course Outline

o   Lecture 1

Sep 11


o   Sections 1.2 and 1.3

o   Watch a nice talk on The Growth of Cryptography by Professor Ronald Rivest.


o   Lecture 2

Sep 13


o   Sections 1.4


o   Lecture 3

Sep 15

Stream Ciphers

o   Sections 2.1 and 2.2


o   Lecture 4


Sep 18

Stream Ciphers

o   Sections 2.3.1 and 2.3.2

o   Assignment # 1


o   Lecture 5


Sep 20

Stream Ciphers

o   Sections 2.3.1 and 2.3.2


o   Lecture 4-6


Sep 22

Overview of AES

o   Sections 4.1 and 4.2


o   Lecture 7


Sep 25

Galois Field


o   Section 4.3


o   Lecture 8


Sep 27

Internal Structure of AES


o   Sections 4.4.1 and 4.4.2


o   Lecture 9


Sep 29

Decryption of AES


o   Section 4.5


o   Lecture 10


Oct 2

Modes of Operations  (ECB, CBC, CTR)


o   Assignment 1 is due in class (hard copy).

o    Honesty declaration form 


o   Sections 5.1.1, 5.1.2, and 5.1.5


o   Lecture 11


Oct 4

Introduction to Public-key Cryptography

o   Sections 6.1 and 6.2

o   Assignment # 2


o   Lecture 12

Oct 11

Euclidean Algorithm, Extended Euclidean Algorithm


o   Sections 6.3.1, 6.3.2



o   Lecture 13

Oct 13

Euclidean Algorithm, Extended Euclidean Algorithm



o   Sections 6.3.1, 6.3.2



o   Lecture 14

Oct 16

Eulerís Phi Function, Fermatís Little Theorem and Eulerís Theorem


o   Sections 6.3.3, 6.3.4



o   Lecture 15

Oct 18

Introduction to RSA cryptosystem


o   Sections 7.1, and 7.2



o   Lecture 16

Oct 20

Key Generation and Proof of Correctness


o   Section 7.3


o   Assignment 2 is due in class (hard copy).



o   Lecture 16 and 17

Oct 23

Fast Exponentiation

o   Section 7.4


o   Lecture 18

Oct 25

Midterm review



Oct 27

o   Midterm in class


o   Syllabus: Chapters 1, 2, 4, 5, and 6 (only those sections that we covered in class)


Oct 30

Diffie-Hellman Key Exchange


o   Sections 8.1


o   Lecture 19


Nov 1

Groups and Cyclic Groups,

Security of DHKE

o   Sections 8.2.1, 8.2.2, 8.4


o   Lecture 19 and 20


Nov 3

Digital Signatures


o   Assignment # 3

o   Sections 10.1 and 10.2.1



o   Lecture 21


Nov 6

Motivation of Hash Function

o   Section 11.1


o   Lecture 22


Nov 8

Security Requirement of Hash Function

o   Section 11.2


o   Lecture 23


Nov 10

Overview of Hash Algorithm

o   Section 11.3


o   Lecture 23 and 24

Nov 15

Principles of MACs

o   Section 12.1


o   Lecture 25


Nov 17


o   Assignment 3 is due in class (hard copy).

o   Section 12.2 and 12.3

o   Assignment # 4



o   Lecture 25 and 26


Nov 20

Class Cancelled




Nov 22

Key Establishment


o   Section 13.1


o   Lecture 27

Nov 24

Key Establishment


o   Section 13.2


o   Lecture 27 and 28

Nov 27

Class Cancelled



Nov 29

Key Establishment


o   Section 13.3


o   Lecture 29

Dec 1

Elgamal Encryption Scheme

o   Assignment 4 is due in class (hard copy).

o   Lecture 30

Dec 4

Garbled Circuit

Not part of exam


Dec 6

Oblivious Transfer

Not part of exam


Dec 8

Final review



Dec 16

Final Exam

o   Time: 1:30 PM; location: E2-110

o   Syllabus: Everything except Chapters 1, 2