CS255: Introduction to Cryptography

Introduction to Cryptography

Winter 2019

Cryptography is an indispensable tool for protecting information in computer systems. This course explains the inner workings of cryptographic primitives and how to correctly use them.


Course syllabus (and readings)
Course overview (grading, textbooks, coursework, exams)
Lectures: Monday, Wednesday, 1:30-2:50pm, Nvidia Aud.
Sections: Friday, 2:30-3:20pm, Thornton 102
Questions for CAs: cs255ta@cs.stanford.edu or use Piazza
Videos: cs255 online   (for video lectures and slides covering the material in class)


All homework submission is to be done via Gradescope. Please use course code 9VBN5X to sign up. Note that Gradescope requires that the solution to every problem start on a new page.

Homework #0:   [html]
Due: Jan. 14
Homework #1:   not out yet
Due: Jan. 28
Homework #2:   not out yet
Due: Feb. 18
Homework #3:   not out yet
Due: Mar. 4


Project #1 (password manager):   not out yet
Due: Monday, Feb. 4, 11:59pm
Project #2 (chat client):   not out yet
Due: Mon., March 18, 11:59pm



  • Basic number theory fact sheet I, primes:   [pdf]
  • Basic number theory fact sheet II, composites:   [pdf]
  • A Primer on number theory for computer scientists: [pdf]