BTI 4202, FS 2026

General information

The course will primarily be taught in English or German by Christian Grothoff, but some lectures will be covered by other lecturers. There will be a final written exam. The date and location of the final exam is yet to be determined by the department. There is a Git repository for the course at https://gitlab.ti.bfh.ch/teaching/bti4202/fs25.

If you have any questions, you can contact me at any time: Christian Grothoff, in Biel, Höheweg 80, Raum N.474.

Content

The lecture will cover the following topics:

• Introductory overview on IT security
• Symmetric encryption and secure channels
• Blockchains
• Shamir secret sharing
• Symmetric key management
• Discussion of selected vulnerabilities and attacks on cryptosystems and real-world deployments
• Certificates, especially X.509
• Centralized and decentralized Public key infrastructures
• Security in distributed systems
• Secure channels: TLS, forward secrecy, future secrecy, repudiation
• Blind signatures
• Anonymity and anonymous digital cash

20.2.2026: Introduction to Computer Security

Preparation

• Why key generation matters

Materials

• Slides: Introduction to Computer Security

Further reading

• Why Tolkien hated Dune
• Virtue ethics
• JTRIG
• Perfectly legal
• Goebels
• Advanced Persistent Threat

6.3.2026: AI and Computer Security

Preparation

• As Israel uses US-made AI models in war, concerns arise about tech's role in who lives and who dies

Materials

• Slides: AI and Computer Security

Further reading

• Skynet
• Tay II
• Tay III
• Hackig back
• Communication in a world of pervasive surveillance, Chapter 4
• AI will cure cancer
• AI's "human in the loop" isn't

20.3.2026: Distributed Systems

Materials

• Slides: Distributed Systems

Exercises

• Distributed exercise

Further reading

• A Thorough Introduction to Distributed Systems
• SLAP and FLOP

27.3.2026: Availability & Key Management

Materials

• Slides: Availability
• Slides: Key management

Exercises

• Availability exercise
• Key management exercise

Further reading

• Postgresql
• GNU Anastasis

3.4.2026: Blockchains & Secure Integration

Materials

• Slides: Blockchain
• Slides: Secure Integration

Exercises

• Blockchain exercise
• Integration exercise

Further reading

• Tether
• Applications
• Blochains, NFT and DeFi
• Accelerando
• The deep links crash course
• sPACE Attack: Spoofing eID's Password Authenticated Connection Establishment

10.4.2026: Osterferien (no lecture)

Preparation

17.4.2026: Secure Channels

Preparation

• Intercepting Mobile Communications: The Insecurity of 802.11

Materials

• Slides: Secure Channels

Exercises

• OR exercise
• SC exercise
• Code for crypto exercise

Further reading

• Symmetric Encryption by Mihir Bellare and Phillip Rogaway
• Authenticated Encryption: Combining Authentication with Encryption to get IND-CCA (by Nick Hopper)
• Mailto Me Your Secrets
• How is SSL hopelessly broken? Let us count the ways

24.4.2026: Certificates and trust (X.509)

Materials

• Slides: Certificates and trust

Further reading

• MD5 considered harmful today

1.5.2026: Centralized public-key infrastructures

Materials

• Folien

8.5.2026: Decentralized public-key infrastructures

Materials

• Slides: Decentralized public-key infrastructures

Exercises

• DPKI exercise

Further reading

• LSD 0001
• LSD 0003
• HACIENDA
• Treasure Map
• Stellar

15.5.2026: Auffahrt (no lecture)

22.5.2026: Anonymity

Materials

• Slides: Anonymity

Exercises

• Anonymity exercise

Further reading

• Attacks on Tor
• Panoramix

Note

Afternoon is also BTI 4202: "E-Voting"!

29.5.2026: Blind Signatures

Materials

• Slides: Blind Signatures

Exercises

• Blind Signatures exercise
• rsa.py

Further reading

• IETF PrivacyPass WG
• Adding Schnorr's Blind Signature in Taler

5.6.2024: GNU Taler

Materials

• GNU Taler

Exercises

• TBD

Further reading

• taler.net
• age restrictions