Cryptographic Protocols with Complex Functionalities

17th May 2017, University of Bristol, Bristol, UK

The ECRYPT-CSA project is organizing a one-day workshop on Cryptographic Protocols with Complex Functionalities.


As cryptography becomes more ubiquitous the application domain increases. We are now seeing cryptographic solutions being proposed for a number of higher level application domains. Such domains include

  • Electronic Voting Protocols;
  • Electronic Auction Protocols;
  • Cloud Protocols;
  • Smart Grid Protocols;
  • DAA and Other Anonymity Preservation Protocols;
  • Key Exchange and Secure Communication Protocols.
Designing such protocols is a complex task, and the resulting protocols utilize many core cryptologic techniques. The aim of the workshop is two-fold: to survey the state of the art in the area and to chart future research directions. The workshop is addressed to both researchers in the application areas listed above, but also to cryptographers interested in the limits and support provided by existing cryptographic techniques. There will be plenty of scope for discussion.

The workshop will also discuss and provide input to an ECRYPT-CSA deliverable on this topic, and will invite participation from researchers, technologists and potential users.

Confirmed contributors

Programme (tentative)

9:30 - 10:00 Coffee/Registration (Recipes for beurre normand and Simone's chocolate cake)
10:00 - 11:00 Anja Lehmann: Privacy-Preserving Technologies: DAA, Anonymous Credentials and Pseudonym Systems (Slides)
11:00 - 12:00 Cas Cremers: Challenges in Key Agreement and Secure Communication
12:00 - 13:00 Lunch
13:00 - 14:00 Ben Smyth: A formal foundation for voting systems (Slides available upon request)
14:00 - 15:00 Christian Cachin: Cryptography for blockchain and distributed trust
15:00 - 15:30 Tea Break
15:30-17:30 Open Discussion

Selected Abstracts

  • A formal foundation for voting systems by Ben Smyth
    Traditional, paper-based voting systems are reliant on extensive trust assumptions. Unfortunately, instead of being trustworthy, many systems are vulnerable to attacks that could bring elections into disrepute. The shift to electronic voting systems has largely exasperated this problem. In this talk, I show how cryptography can be used to *secure* the voting systems we use in real-life, eliminating the need for blind trust. First, I will present an informal introduction to electronic voting. Secondly, I will review the Helios electronic voting system, and highlight known attacks. Finally, I will present definitions of ballot secrecy and verifiability in the computational model of security, and show that Helios can be patched to satisfy these definitions. The talk is based upon papers with David Bernhard, Michael Clarkson, Veronique Cortier, Steven Frink, and Maxime Meyer (see Ben's publications for details).

Organizers and Contacts

  • Nigel Smart (University of Bristol --,
  • Martijn Stam (University of Bristol -- ),
  • Bogdan Warinschi (University of Bristol --


Participation in the workshop was free and is no longer possible. For questions regarding the workshop, please register by e-mailing Martijn Stam (using the email address above).


The workshop took place in the Merchant Venturers Building at the University of Bristol, UK. Talks were held in room MVB 1.06.