Seminar: Practical Cryptographic Systems

Seminar in Winter 2012/13 Semester

Instructor: Dr. Aniket Kate
Time/Place: Monday 14:15 to 16:00 (E 1.7 Seminar Room 3.23)
Instruction Language: English
Contact Email:


Over the last thirty years, the cryptographic protocols have become an indispensable part for our day-to-day life. We use cryptography when we unlock our cell-phones, perform our banking transactions, and even when we vote during an election.

However, not all of the employed cryptographic constructions have been designed and incorporated in the practical systems with at most care, and every so often we come across much-publicized attacks on the cryptographic systems; e.g., flaws in the random number generators, WEP protocol or satelight phone encryption, side-channel attacks, credit card PIN cracking, and many more. Some of these breaks have severe physical, psychological and economical consequences, and it is important that we learn the lessons from them as we do not want to make similar mistakes while amending to the broken systems, or while designing the new protocols.

In this seminar, we will study some of these practical cryptographic systems used in daily life. We will choose some interesting cryptographic systems from a variety of areas ranging from cryptographic voting to bitcoins.

Presentation Schedule

[05/11/2012] (Trusted Computing)

  • Bootstrapping Trust in Commodity Computers. Bryan Parno, Jonathan M. McCune, Adrian Perrig. IEEE Symposium on Security and Privacy 2010. [PDF]
    Presenters: Vineet Rajani and David Swasey

[12/11/2012] (No Seminar)

[19/11/2012] (Privacy-Enhancing Technologies - I)

  • Untraceable electronic mail, return addresses, and digital pseudonyms. David Chaum. Communications of the ACM, 1981. [PDF]
    Presenter: Edit Kapcari
  • Bitcoin: A Peer-to-Peer Electronic Cash System. Satoshi Nakamoto. [PDF]
    Presenter: Niklas Grimm

[26/11/2012] (Privacy-Enhancing Technologies - II)

  • Tor: The Second-Generation Onion Router. Roger Dingledine, Nick Mathewson, and Paul Syverson. USENIX Security 2004. [PDF]
    Presenter: Mark Simkin
  • Shining Light in Dark Places: Understanding the Tor Network. Damon McCoy, Kevin Bauer, Dirk Grunwald, Tadayoshi Kohno, and Douglas Sicker. PETS 2008. [PDF]
    Presenter: Immo Stanke

[03/12/2012] (Censorship Resistance)

  • How the Great Firewall of China is Blocking Tor. Philipp Winter and Stefan Lindskog. FOCI 2012. [PDF]
    Presenter: Jonas Schneider
  • Telex: Anticensorship in the Network Infrastructure. Eric Wustrow, Scott Wolchok, Ian Goldberg, and J. Alex Halderman. USENIX Security 2011 ( [PDF]
    Presenter: Tim Ruffing

[10/12/2012] (Weak Keys)

  • Public Keys or Ron was wrong, Whit is right. Arjen K. Lenstra, James P. Hughes, Maxime Augier, Joppe W. Bos, Thorsten Kleinjung, Christophe Wachter. CRYPTO 2012. [PDF]
    Presenter: Sara Pourghorban
  • Mining Your Ps and Qs: Detection of Widespread Weak Keys in Network Devices. Nadia Heninger, Zakir Durumeric, Eric Wustrow, J. Alex Halderman. Usenix Security 2012. [PDF]
    Presenter: Karsten Knuth

[17/12/2012] (Wireless (In)security)

  • Intercepting mobile communications: the insecurity of 802.11. Nikita Borisov, Ian Goldberg, and David Wagner. MOBICOM 2001. [PDF]
    Presenter: Andrey Chernov
  • Don't Trust Satellite Phones: A Security Analysis of Two Satphone Standards. Benedikt Driessen, Ralf Hund, Carsten Willems, Christof Paar, and Thorsten Holz. IEEE Symposium on Security and Privacy 2012. [PDF]
    Presenter: Iulia Bolosteanu

[14/01/2013] (Attacks)

  • Lest We Remember: Cold Boot Attacks on Encryption Keys. .J. Alex Halderman, Seth D. Schoen, Nadia Heninger, William Clarkson, William Paul, Joseph A. Calandrino, Ariel J. Feldman, Jacob Appelbaum, and Edward W. Felten. Usenix Security 2008. [PDF]
    Presenter: Eslam Elnikety
  • Chip and PIN is Broken. Steven J. Murdoch, Saar Drimer, Ross Anderson, Mike Bond. IEEE Symposium on Security and Privacy 2010. [PDF]
    Presenter: Niklas Brachmann

[21/01/2013] (Voting Protocols)

  • Helios: Web-based Open-Audit Voting. Ben Adida. Usenix Security 2008. [PDF]
    Presenter: Frederic Endner-Duehr
  • Clash Attacks on the Verifiability of E-Voting Systems. Ralf Kusters, Tomasz Truderung, and Andreas Vogt. IEEE Symposium on Security and Privacy 2012. [PDF]
    Presenter: Lisette Espin Noboa

[28/01/2013] (Project Proposal Presentations)

Requirement for Obtaining Credit Points (Short Summary)

  • Prepare and give a 30-minute presentation for your selected paper.
  • Write a review for at least one of the two papers for every class period.
  • Attend and actively participate in the paper discussions moderated by the presenters. If you are ill, let us know in advance.
  • Prepare a short proposal and 5-page report for your project.
  • Prepare and give a 10-minute presentation for your project.
You can also earn bonus points by performing better than expected in class discussions, your paper-reviews or your project. For more details see Course Structure below.

Note that for project ideas possibly leading to publications with more efforts, it is possible to extend them for an additional master practical training (6-credit points). We expect to generate at least two-three workshop-quality publications from the course, and encourage students to put more efforts towards their projects.

Course Structure

The seminar will primarily consist of reading, reviewing, and presenting research papers and working on a small research project. Your grade in the course depends upon the following four task:
Paper Presentation40%
Paper Reviews20%
Class Participation10%
Course Project30%

Paper Presentation

Two papers will be assigned to each class period. All students should read both of the papers before the class, and submit a review for at least one of them (of the student's choice) before the class starts. A conference-style review submission webpage is available here.

Each paper will be presented to the class by one student, in a 30-minute presentation. The student presenting the paper will then lead the class in a discussion of the paper, taking 45 minutes for the presentation and discussion in total for each paper. We will also save 5 minutes during these 45 minutes to give a constructive feedback to the presenter.


Students are expected to work in pairs on an original research project on some topic related to cryptographic systems. Each pair will submit a proposal to the instructor by December 24, 2012 January 14, 2013. Students will be provided some feedback on their proposals by January 21, 2013. On January 28, 2013, they will present their proposal/work to the class with a 10-minute presentation.

In addition, by the end of the semester, they will produce a 5-page report describing their project. It is also possible to make a group of different sizes; however, the expectations may vary accordingly.

Bonus Points

You can also earn bonus points by performing better than expected in class discussions, your paper-reviews or your project. They will improve your grade in the following ways. One bonus point corresponds to a third mark in the German grading system. therefore, three bonus points will improve your final grade by a full mark, e.g., from 2.7 (C+) to 1.7 (B+).
  • For every two above expectation paper-reviews, you will be awarded one bonus point.
  • For an excellent project (with an emphasis on novelty), you will be awarded one bonus point.
  • For the best participation in classroom discussions, two students will be awarded one bonus point each.

Useful Links

  • Organizational Meeting Slides: [PDF]
  • A nice article about paper reading: How To Read a Paper by S. Keshav [PDF]