If you are interested in cryptography, there is very good YouTube video: Theory and Practice of Cryptography. You’ll need one hour of time to watch it.
Topics include: Introduction to Modern Cryptography, Using Cryptography in Practice and at Google, Proofs of Security and Security Definitions and A Special Topic in Cryptography.
This talk is one in a series hosted by Google University. Speaker is Steve Weis. He received his PhD from the Cryptography and Information Security group at MIT, where he was advised by Ron Rivest. He is a member of Google’s Applied Security (AppSec) team and is the technical lead for Google’s internal cryptographic library, KeyMaster.