Math 4981: Cryptography
Spring 2021

Contact Info
Spring 2021

Office: Blackboard

Office Hours (Tentative):

Course Information


Official textbook:

Daily Assignments

January 28:

January 26: Block Ciphers and the Hill Cipher

January 21:


January 19: Polyalphabetic ciphers


January 14: Cryptanalysis of Monoalphabetic Ciphers


January 12: Syllabus and Intro to Encryption


Course Goals

Cryptography is the study of sending secret messages over insecure communication channels. Cryptographic capabilities are important to politics and foreign affairs, and underlie the functioning of a great deal of the modern economy.

Unlike many math courses, this course will be oriented around a problem we’re trying to solve, rather than around a set of techniques. We’ll draw on basic ideas from fields including combinatorics, information theory, probability theory, number theory, geometry, and algebra to encrypt messages so they can’t be intercepted, and to break encryption schemes and interpret those secret messages sent by others.

In this course we will:

The course syllabus is available here.

Course notes


Final Project

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I will be basing much of this course off material from the book An Introduction to Mathematical Cryptography by Hoffstein, Pipher, and Silverman. This book seems to be freely available with your GWU login, so please go download the PDF from the above link. However, you should not ever need access to the book.