CS 127 / CSCI E-127: Cryptography

About this course

Cryptography is as old as human communication itself, but has undergone a revolution in the last few decades. It is now about much more than "secret writing" and includes seemingly paradoxical notions such as communicating securely without a shared secret, and computing on encrypted data. In this challenging but rewarding course we will start from the basics of private and public key cryptography and go all the way up to advanced notions such as fully homomorphic encryption and indistinguishability obfuscation. This is a proof-based course that will be best appreciated by mathematically mature students.

For more information about this course, please see the following document on Foreword, Syllabus and Prerequisites. The recommended textbook for this class is Introduction to Modern Cryptography (2nd ed) / Katz and Lindell though we will only be loosely following it (and teach many topics not covered by it).

For some of the mathematical background, see the notes for the "Lecture 0" on mathematical background. The exercises there will be part of the first problem set, so you can save yourself time by starting on them now.

Should I take this course? If you are interested in both the foundations of cryptography as well as some of its exciting recent applications, and are comfortable with mathematical proofs and abstract reasoning, this course might be for you. If you are a Harvard student wondering if you should take this course, send me an email and I'll be happy to set up a time to meet and talk about it in person.

During shopping week (Jan 24-30) I will have the following extended office hours if you want to talk to me: Monday (1/25) 2-3pm, Tuesday (1/26) 1pm-2:30pm, Thursday (1/28) 2pm-3pm, Friday (1/29) 2pm-3pm.

See this page for more administrative information about this course.

Reading

As mentioned above, the recommended textbook for this course is Katz and Lindell's Intrduction to Modern CRyptography (2nd ed). Another text we will refer to occasionally is Boneh and Shoup's Graduate Course on Applied Cryptography. A very comprhenesive text on the theory of cryptography is Goldreich's two volume "Foundations of Cryptography". There are several lecture notes on the web for cryptography courses; a fairly complete set of notes is Pass and Shelat's. A more applied cryptography text is Menezes et al's Handbook of Applied Cryptography. Finally, Dan Boneh has taught a MOOC on cryptography which is available on Coursera (Part I) and (Part II)

Tentative plan

(very much subject to change!)

Submit all homework and quizzes via the canvas website for the course.