Course objective

As some of you in the course might have observed, we have opted to omit several details regarding the cryptographic constructions: e.g., construction of PRF from PRG, inner workings of any block-cipher, the Chinese Remainder Theorem, etc. So how would you be able to construct your own encryption scheme?

The objective of this course is not to teach you how to build low-level cryptographic primitives. (We simply won’t have the time to fit everything into a one-semester course.) Instead, we aim to learn what these primitives are and how to use them in a larger system.  In fact, simply using the various cryptographic primitives already calls for some expertise: just too many of them resemble each other (for e.g., those which take an input and a key, and produce an output that looks like gibberish). It is crucial to understand what security property we need for a specific task at hand.

One objective of this course is to introduce you to some of the most important cryptographic primitives used in theory and practice, and provide a good understanding of the security guarantees, the assumptions behind them, the efficiency bottlenecks, and possible trade-offs, so that when you encounter them in a system, you can ask yourself if they are used in a meaningful manner. You can also use these primitives correctly in building higher level schemes. But should you want to build lower level primitives, all that this course can do is to tell you that you’d better make sure you know what you are doing.

(I will have more to say regarding course objectives, later on, but this is the primary objective, in my view.)