Cryptanalysis (SS 2026)

Content

Cryptanalytic attacks define the security of cryptographic algorithms, and understanding them is crucial to understand cryptographic design. This lecture aims to give you some in-depth knowledge of several recent state-of-the-art topics in cryptography, with a focus on cryptanalysis:

• Classic and quantum algorithms for factoring and discrete log
• Cryptanalysis of block ciphers (differential, linear, algebraic)
• Cryptanalysis of hash functions and stream ciphers
• Lattices and continued fractions in cryptanalysis

In the exercises, you will implement some of these attacks to solve cryptanalytic challenges. In the seminar, additional selected topics may be presented by participants -- see below for a list of suggested topics.      

Material

Date	Who	Lecture (15:00-16:45 in CCGEG002)	Video (2021)	Exercises (16:45-17:30 in CCGEG002)
05.03.2026	MN	L1 – Discrete Logarithm	YouTube
12.03.2026	MN	L2 – Factoring and Continued Fractions	YouTube	T1 - Asymmetric Cryptanalysis, Team registration deadline
19.03.2026	MN	L3 – Lattices	YouTube
26.03.2026	MN	L4 – Quantum Cryptanalysis	YouTube
16.04.2026	MS	L5 – TLS security & Protocol Attacks	YouTube
23.04.2026	MS	L6 – Implementation Aspects		T1 - Submission Deadline (15:00)
30.04.2026	you	Exam 1
07.05.2026	SG	L7 – Linear Cryptanalysis	YouTube	T2 - Symmetric Cryptanalysis
21.05.2026	NM	L8 – Sponges & Cube Attacks	YouTube
28.05.2026	SG	L9 – Differential Cryptanalysis	YouTube
11.06.2026	SG	LA – Advanced Differential Attacks	YouTube
18.06.2026	SG	LB – Algebraic Attacks	YouTube	T2 - Submission Deadline (15:00)
25.06.2026	you	Exam 2
16.07.2026	you	Backup Exam

We have a guest talk this year by Nedzma Musovic (L8).

Previous versions of this course: SS 2025, SS 2024, SS 2023, SS 2022, SS 2021 (YouTube playlist), SS 2020

Administrative Information

For questions outside lecture times, contact us via the #cryptanalysis Discord channel or by email.

Exams

There will be 2 written exams during the semester. Each exam contributes 25% to the overall grade. It is possible to retake one exam in July.

Exercises

In the exercises, you implement cryptanalysis techniques from the lecture in teams of 2. You submit your implementations for 2 assignments, which we will discuss with you in 2 assignment interviews ("Abgabegespräche"). The assignment interviews typically happen in the week after the deadline. Each assignment contributes 25% to the overall grade. Use TeachCenter to register your team and git for your submissions.

Grading

For a positive grade, you need at least 50% of the points for the lecture part, i.e., the 2 exams, and at least 50% of the points for the exercise part, i.e., the 2 assignments. We treat the involvement of ChatGPT and similar tools the same way as the involvement of another natural person. That is, for involvement that qualifies as plagiarism or an impermissible level of assistance, the consequences will be the same in both cases to the strictest extent possible.'

Literature

The lecture slides are reasonably self-contained, but often briefly phrased. If you prefer full-text resources, you may find some of the following books interesting:

• The Block Cipher Companion, by L.R. Knudsen and M.J.B. Robshaw
• An Introduction to Mathematical Cryptography, by J. Hoffstein, J. Pipher, and J.H. Silverman

       

Lecture Dates

Date	Begin	End	Location	Event	Type	Comment
2026/06/11	15:00	17:30	Seminarraum	Abhaltung	VU	fix/
2026/06/18	15:00	17:30	Seminarraum	Abhaltung	VU	fix/onetime change of rooms
2026/06/25	15:00	15:15	Seminarraum	Aufbau u. Vorbereitung	VU	fix/
2026/06/25	16:15	16:30	Seminarraum	Nachbereitung	VU	fix/
2026/07/16	15:00	15:15	Seminarraum	Aufbau u. Vorbereitung	VU	fix/
2026/07/16	16:15	16:30	Seminarraum	Nachbereitung	VU	fix/

Lecturers