Cryptographic Protocols research group

Group Description

The research group performs research in the generic area of cryptographic protocols, including but not only

  • Design of efficient zero-knowledge protocols
  • E-voting, esp. including
    • Verifiable (zero-knowledge) mixnets
    • Bulletin boards
  • Blockchain, esp. privacy in blockchain
  • Privacy-preserving data mining and machine learning
  • Relations with coding theory

The group is currently or has been recently funded by the following projects:

  • Panoramix - H2020 project on verifiable mixnets (finished in January, 2019)
  • PRIViLEDGE - H2020 project on privacy in distributed ledgers (will finish in Fall, 2019)
  • PRG49 - Estonian research grant on "Cryptographic Protocols and Coding Theory"

Please see the individual project places for more information about our research.

Team

Alumni (not complete)

  • Sven Laur (defended PhD in 2008, now a senior research fellow in Tartu)
  • Bingsheng Zhang (defended PhD in 2011, now a professor at Zhejiang University, China)
  • Prastudy Fauzi (defended PhD in 2017, now a postdoc in Aarhus)
  • Rafik Chaabouni (defended PhD in 2017, now a IT risk analyst, Pictet Group)
  • Michal Zajac (dblp) (now at Clearmatics, London-based blockchain company)
  • Gennaro Avitabile (Erasmus exchange student from Salerno, Italy, 01.09.18 -- 14.02.18)
  • Hamidreza Khoshakhlagh (Ph.D. student 01.09.18 - 31.05.19, now a PhD student in Aarhus)
  • Zaira Pindado (visiting PhD student, 01.04.19 - 18.06.19)
  • Janno Veeorg (MSc student, -31.07.19)
  • Shahla Atapoor (Msc student, -31.08.19)
  • Toomas Krips (dblp, -31.08.19, now a postdoc in Stuttgart)

Recent Publications

2016

  1. Prastudy Fauzi, Helger Lipmaa and Michał Zając. A Shuffle Argument Secure in the Generic Model. In Jung Hee Cheon and Tsuyoshi Takagi, editors, ASIACRYPT 2016, volume ? of Lecture Notes in Computer Science, pages 841--872, Hanoi, Vietnam, December 4--8, 2016. Springer, Heidelberg.
  2. Helger Lipmaa. Prover-Efficient Commit-And-Prove Zero-Knowledge SNARKs. In David Pointcheval, Abderrahmane Nitaj and Tajjeeddine Rachidi, editors, Africacrypt 2016, volume 10032 of Lecture Notes in Computer Science, pages 200--216, Fes, Morocco, April 13--15, 2016. Springer, Heidelberg. Invited to IJACT as one of the three best papers
  3. Prastudy Fauzi and Helger Lipmaa. Efficient Culpably Sound NIZK Shuffle Argument without Random Oracles. In Kazue Sako, editor, CT-RSA 2016, volume 9610 of Lecture Notes in Computer Science, pages 200--216, San Franscisco, CA, USA, February 29--March 4, 2016. Springer, Heidelberg.

2017

  1. Helger Lipmaa. Prover-efficient commit-and-prove zero-knowledge SNARKs. International Journal of Applied Cryptography (IJACT), Vol. 3, No. 4, 2017. This is an invited journal version of the earlier Africacrypt 2016 paper
  2. Behzad Abdolmaleki, Karim Baghery, Helger Lipmaa and Michal Zajac. A Subversion-Resistant SNARK. In Thomas Peyrin and Tsuyoshi Takagi, editors, ASIACRYPT (3) 2017, volume 10626 of Lecture Notes in Computer Science, pages 3--33, Hong Kong, China, December 3--7, 2017. Springer, Heidelberg. Invited to Journal of Cryptology as one of the three best papers
  3. Prastudy Fauzi, Helger Lipmaa, Janno Siim and Michal Zajac. An Efficient Pairing-Based Shuffle Argument. In Thomas Peyrin and Tsuyoshi Takagi, editors, ASIACRYPT (2) 2017, volume 10625 of Lecture Notes in Computer Science, pages 97--127, Hong Kong, China, December 3--7, 2017. Springer, Cham.
  4. Helger Lipmaa and Kateryna Pavlyk. A Simpler Rate-Optimal CPIR Protocol. In Aggelos Kiayias, editor, FC 2017, volume ? of Lecture Notes in Computer Science, pages ?--?, Malta, April 3--7, 2017. Springer, Heidelberg. Accepted.
  5. Helger Lipmaa. Optimally Sound Sigma Protocols Under DCRA. In Aggelos Kiayias, editor, FC 2017, volume ? of Lecture Notes in Computer Science, pages ?--?, Malta, April 3--7, 2017. Springer, Heidelberg. Accepted.
  6. Florian Bourse, Fabrice Benhamouda and Helger Lipmaa. CCA-Secure Inner-Product Functional Encryption from Projective Hash Functions. In Serge Fehr, editor, PKC 2017, volume 10175 of Lecture Notes in Computer Science, pages 36--66, Amsterdam, Netherlands, March 28--31, 2017. Springer, Heidelberg.

2018

  1. Aggelos Kiayias, Annabell Kuldmaa, Helger Lipmaa, Janno Siim and Thomas Zacharias. On the Security Properties of e-Voting Bulletin Boards. In Dario Catalano and Roberto de Prisco, editors, SCN 2018, volume 11035 of Lecture Notes in Computer Science, pages 505--523, Amalfi, Italy, September 5--7, 2018. Springer, Cham.
  2. Sven Heiberg, Ivo Kubjas, Janno Siim and Jan Willemson. On Trade-offs of Applying Block Chains for Electronic Voting Bulletin Boards. In Proceedings of the Third International Joint Conference on Electronic Voting E-Vote-ID 2018, 2–5 October 2018, Lochau/Bregenz, Austria, TUT press, pp. 259-276. Available at http://eprint.iacr.org/2018/685

2019

  1. Behzad Abdolmaleki, Karim Baghery, Helger Lipmaa, Janno Siim and Michal Zajac. DL-Extractable UC-Commitment Schemes. In Robert Deng and Moti Yung, editors, ACNS 2019, volume 11464 of Lecture Notes in Computer Science, pages 385--405, Bogotá , Colombia, June 5--7, 2019. Springer, Heidelberg. eprint version
  2. Behzad Abdolmaleki, Karim Baghery, Helger Lipmaa, Janno Siim and Michal Zajac. UC-Secure CRS Generation for SNARKs. In Johannes Buchmann, Abderrahmane Nitaj and Tajjeeddine Rachidi, editors, Africacrypt 2019, volume 11627 of Lecture Notes in Computer Science, pages 99--117, Rabat, Morocco, July 9--11, 2019. Springer, Heidelberg.
  3. Karim Baghery. On the Efficiency of Privacy-Preserving Smart Contract Systems. In Johannes Buchmann, Abderrahmane Nitaj and Tajjeeddine Rachidi, editors, Africacrypt 2019, volume ? of Lecture Notes in Computer Science, pages ?--?, Rabat, Morocco, July 9--11, 2019. Springer, Heidelberg.
  4. Shahla Atapoor and Karim Baghery. Simulation Extractability in Groth's zk-SNARK. CBT 2019, September 26-27, 2019, University of Luxembourg, Luxembourg.
  5. Behzad Abdolmaleki and Daniel Slamanig. A Framework for UC-Secure Commitments from Publicly Computable Smooth Projective Hashing. IMA CC 2019.
  6. Karim Baghery. Subversion-Resistant Simulation (Knowledge) Sound NIZKs. IMA CC 2019.

2020

  1. Janno Siim, Prastudy Fauzi, Michał Zając, Panos Louridas, Foteinos Mergoupis-Anagnou, Georgios Korfiatis, and Antonis Aggelakis. A Non-Interactive Shuffle Argument With Low Trust Assumptions. Accepted to CT-RSA 2020
  2. Behzad Abdolmaleki, Helger Lipmaa, Janno Siim and Michał Zając. On QA-NIZK in the BPK model. In Aggelos Kiayias, editor, PKC 2020, volume ? of Lecture Notes in Computer Science, pages ?--?, Edinburgh, UK, May 4--7, 2020. Springer, Cham. Accepted.