An intensive introduction to Cryptography

An intensive introduction to Cryptography:

These are … lecture notes for an introductory but fast-paced undergraduate/beginning graduate course on cryptography. I am using these notes for Harvard CS 127.
You can also download all lecture notes in a single PDF file.

I am diving in. I thought I had a decent grasp on the basics of cryptography but I am learning a ton with this so far.

If you have any comments, suggestions, typo fixes, etc.. I would be very grateful if you post them as an issue or pull request in the GitHub repository where I am maintaining the source files for these notes.

What resources are you using?
Are you finding things that challenge your understanding and assumptions?

Be nice with what you write.