This module we started getting serious about quantum information – and cryptography. As usual we recommend that the first thing you do is go through the lecture notes for the module (they are available in the module “Lecture notes”) carefully and make sure you are able to do all the optional exercises included in the notes.

If you have a mathematical mindset and would like to go a little deeper into the formalism of general quantum states and operations, the lecture notes by John Watrous are a great resource, very precise and detailed.

The one-time pad is the first and only classical cryptosystem with information-theoretic security. If you are interested in reading more about Shannon’s theorem, and the foundations of modern classical cryptography in general, the first chapter in the lecture notes by Pass and Shelat is a great starting point.

The quantum one-time pad plays a similarly fundamental role in quantum cryptography. Don’t forget about it: it will make an essential come-back in module 10, when we discuss the problem of delegated computation. The quantum one-time pad is closely related to teleportation, which we won’t cover directly but you can read about in many places (such as the notes by Watrous linked to above).

Go ahead and work on the problem sets. Once you’ve completed them, you’ll have mastered all the basics of quantum information you will need for the course. Next module, we’ll exercise the notions we learned to give a little tour of quantum entanglement, its many fascinating properties…and their use for cryptography!