Authentic Key Agreement: Formal Models and Applications

Graduate Course, Ruhr University Bochum, 2022

  • Lecturer: Prof. Dr. Schwenk
  • Language: German
  • Credits: 5CP
  • Programs: M.Sc. IT-Security
  • Examination: 100 % Written Exam (120 Minutes) + 10 % Homework

Prior Knowledge

  • Cryptography Basics

Learning Outcomes

Students understand the special nature of cryptographic protocols, in which the focus is no longer centered on an algorithm but on the interaction of different units. They know the most important concepts regarding the provable security of protocols. The most important building blocks of cryptographic protocols are covered so that students are able to enter directly into the scientific literature on this topic.

Course Description

This lecture provides an introduction to the field of cryptographic protocols describing the use of knoen and new methods of cryptography in communication between multiple entities. Emphasis is placed on both descriptions and security. The lecture covers the following topics:

  • Cryptographic basics (brief review of probability theory, information theory, etc.)
  • Provable security
  • Analysis of key exchange protocols with special focus on practical example protocols (like TLS or SSH)


  1. Introduction
  2. Key Exchange / Agreement Protocol
  3. Authentication Protocols
  4. Authenticated Key Exchange (AKE)
  5. Transport Layer Security (TLS)
  6. Truncated TLS is a Secure AKE Protocol
  7. The ACCE model
  8. TLS is a Secure ACCE Protocol
  9. One-Round-Key Exchange Protocols (ORKE)