CSCI 4331/6331 - Cryptography - Fall 2022

Monday, Wednesday 12:45-2:00
Funger Hall 209

Instructor Information

Name: Arkady Yerukhimovich (He/Him)
Office: SEH4570
Office hours: M 10:30-11:30 (in person and Zoom), T 1:00-2:00 (Zoom only)

Course description

This course will introduce students to modern cryptography with a focus on formal definitions and provably secure constructions of cryptographic protocols. Topics covered will include secret-key and public-key encryption, message-authentication codes, digital signatures, and advanced topics. See syllabus for additional details.


Jonathan Katz, Yehuda Lindell: "Introduction to Modern Cryptography. Second Edition." CRC Press 2014. (Available for free through GW libraries.)

Online Resources

We will make use of the following online resources for this course. For all interactions, both online and in person, it is critical that all students abide by the Online Social Contract to ensure civil, and productive discourse.


Exam(s)40% (20% each)
Research project20%
Class participation10%

Homework policy

Homework will be assigned weekly. Homework is due before class (by 12:45PM) on the due date. It must be submitted via Blackboard by this time to receive credit. Homework can be typed using your favorite tool (I am happy to help anybody interested in learning LaTex) or handwritten and scanned. But, make sure that what you submit is legible as it is what will be graded. No late homeworks will be accepted!

Students are welcome to work together on homeworks, however each student must write up and submit their own solutions. If you work on the homework with someone else, you MUST acknowledge them on your submitted homework. The solutions you submit MUST be your own.

The final homework grade will be the average of all homework scores with the two lowest scores dropped.

Laptop policy

I ask that students not use laptops or other electronic devices in class. I will make sure to lecture at a pace that allows for hand-written notes. If you need to use an electronic device for note taking, please come talk to me.

Tentative schedule

This is a tentative schedule for the class. The updated schedule will be on Blackboard.

DateLecture Topic(s)
Week 1Aug. 29Introductions, Syllabus review, Probability review
Aug. 31Perfectly secure encryption, one-time pad
Week 2Sep. 5No class -- Labor Day
Sep. 7Limits of perfect secrecy, Computationally-secure encryption
Week 3Sep. 12Proofs by reduction, pseudorandom generators
Sep. 14PRG+OTP secure encryption, CPA security
Week 4Sep. 19Pseudorandom functions
Sep. 21Construction of CPA-secure encryption
Week 5Sep. 26Encryption modes of operation
Sep. 28Padding oracle attack
Week 6Oct. 3Message authentication codes
Oct. 5CCA-security, authenticated encryption
Week 7Oct. 10Hash functions
Oct. 12Hash function applications
Week 8Oct. 17Midterm review
Week 9Oct. 24No class -- Fall break
Oct. 26Practical constructions of symmetric-key primitives part 1 (AES)
Week 10Oct. 26Practical constructions of symmetric-key primitives part 2 (DES)
Nov. 2Number theory
Week 11Nov. 7Group theory
Nov. 9Cryptographic assumptions
Week 12Nov. 14Key exchange
Nov. 16Building public-key encryption from key exchange
Week 13Nov. 21El Gamal and RSA encryption schemes
Nov. 23No class -- Thanksgiving
Week 14Nov. 28Digital signatures part 1
Nov. 30Digital signatures part 2
Week 15Dec. 5Advanced Topics
Dec. 7Research project presentations
Week 16Dec. 12Exam review

Diversity and Student Behavior

It is my intent that students from all diverse backgrounds and perspectives be well served by this course. I will try to present materials and activities in ways that are respectful of diversity: gender, sexuality, disability, age, socioeconomic status, ethnicity, race, and culture. Your suggestions for how to improve this are encouraged and appreciated.

This class will involve a significant amount of in-class discussion and group work. It is critical that students treat each other with respect. This is important both for in-person discussions and any online discussions. Respect peoples' opinions, and do not discourage your classmates. If we can all learn together, we all benefit.