CSIC 4331/6331 - Cryptography

Tuesdays, 12:45
Online (via Blackboard)

Instructor Information

Name: Arkady Yerukhimovich
Email: arkady@gwu.edu
Office hours: Mondays 3:00 PM - 4:00 PM, Fridays 10:00 AM - 11:00 AM.
Office hours will be held via Zoom. Students must email me for link if they want to attend.

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 in GW Libraries.)

Technology for Online Instruction

This will be an entirely online class for the Fall 2020 semester. Since all interactions (both synchronous and asynchronous) will be virtual, it is critical that all students abide by the Online Social Contract to ensure civil, and productive discourse. The course material will be accessible as follows:


All lectures will be pre-recorded and shared via Blackboard (under "Outline"). Videos of the lectures along with a lecture outline, and the corresponding slides will be available immediately after the preceding synchronous class (i.e., lectures for week 2 material will be available after the synchronous session on week 1). Students are expected to watch all lectures prior to the synchronous session for the week.

Synchronous sessions:

The synchronous sessions will be held at 12:45PM on Tuesdays via Blackboard Collaborate Ultra (accessible under Tools in Blackboard). These sessions will be used to review material from the video lectures, review homework, and for quizzes. The synchronous sessions will be recorded and shared via Blackboard.

Discussion Boards:

The asynchronous discussion for the course will use Blackboard discussion boards (accessible under Discussions). These will be used to ask and answer questions about the video lectures.


All homework will be posted, collected, and graded via Blackboard.

Office Hours:

Office hours will be held via Zoom.


Research Project25%
Class participation10%

Homework policy:

Homeworks will be assigned approximately every two weeks. Homeworks are due before class (by 12:45PM) on the due date. They must be submitted via Blackboard by this time to receive credit. Homeworks 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.

Additionally, you may use outside resources (e.g., web search, other text books, lecture notes) to help with the homework. However, if you use any such resource, you MUST cite them appropriately. Moreover, the solutions you submit MUST be your own. Make sure to write-up your own answers and that you understand them, copying and pasting solutions is not acceptable. Submitted homeworks violating these guidelines will be considered in breach of the academic integrity code and will be prosecuted accordingly.

There will be 6-7 homework assigments over the course of the semester. The final homework grade will be the average of all homework scores with the lowest score dropped.

Class Participation:

While the class will be entirely online, there is still an expectation of class participation. Students should make an effort to attend the synchronous sessions. However, the main avenue for participation will be via the discussion boards. The expectation is that students will use these boards to ask an answer questions about the week’s lectures. Each week, each student should post at least one question and answer at least one other question on the bulletin board. Additionally, students should vote for questions to be discussed at the next synchronous session. These votes must be in by the Friday before.


There will be one take-home exam in this course. You will have 48 hours to complete the exam. The exam will begin immediately after the synchronous session on December 1.

Research Project

The students will complete a research project due at the end of the semester.

Tentative schedule

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

DateLecture Topic(s)
Sep. 1Introductions, Syllabus review
Sep. 8Modern cryptography, probability review, perfectly secure encryption, one-time pad
Sep. 15Computationally-secure encryption, proofs by reduction, pseudorandom generators
Sep. 22PRG+OTP secure encryption, CPA security, pseudorandom functions
Sep. 29Construction of CPA-secure encryption
Oct. 6modes of operation, CCA-secure encryption, padding oracle attack
Oct. 13Message authentication codes definitions and constructions, authenticated encryption, hash function definitions and applications
Oct. 20Practical constructions of symmetric-key primitives, DES, 3DES, AES, Feistel networks
Oct. 27Number theory, group theory
Nov. 3Cryptographic assumptions, Key exchange, Public-key encryption, Diffie-Hellman
Nov. 10El Gamal, RSA, Paillier, CCA security
Nov. 17Digital signatures
Nov. 24Student project presentations
Dec. 1Advanced Topics, review for exam