April 2025
I’ll present some case studies of how the fundamental cryptographic primitives are used to secure large-scale applications including TLS 1.3, Bluetooth, Amazon Web Services (AWS), and Signal. An emphasis will be placed on the challenges with managing a very large number of secret keys and public keys.
Note to instructors
If you are teaching a course in applied cryptography and would like to use my video lectures as a secondary source or a primary source, please send me an email message. I will be happy to arrange a meeting with you, to tell you about my experience teaching applied cryptography over the past 30 years, and we can have a discussion about the curriculum, exercises, projects, and tests for your course. If you use any of the resources (videos or slides) on this web page in your classes, please do provide your students a link to my page (cryptography101.ca).
YouTube Lectures
V0: Welcome note
V1: Overview
V2: Public-key infrastructures (PKI)
V3: Transport Layer Security (TLS 1.3)
Additional Material
Errata (last updated: Nov 27, 2025)
Here is a list of errors in the video lectures. These errors have already been corrected in the lecture slides (available below).
- Slide 34 (V2): “stored” should be “stores”
- Slide 41 (V3): “four key” should be “four keys”
Lecture slides
NEW: Chapters from “Textbook of Applied Cryptography”
Supplementary readings
- V4: Bluetooth security argument (slide 70)