Greg* Alpár

Greg Alpár
is assistant professor at the Open Universiteit / Department of Computer Science and researcher at the Radboud University / Institute for Computing and Information Sciences / Digital Security group. I am also a member of the PI.lab.

Previously I was a post-doctorate lecturer and researcher at RU's Faculty of Science Institute for Computing and Information Sciences (ICIS) department within the Digital Security group, after finishing my PhD project also there. During my PhD I was also a member of the TNO Security department. My background is mathematics and education (Master of Science at ELTE, Budapest, Hungary), coding theory and cryptography (Professional Doctorate in Engineering at TU/e in Eindhoven, The Netherlands, in the program Mathematics for Industry). My Ph.D. was about about Attribute-based identity management.

Keywords. mathematics education, cryptography, privacy, attribute-based identity management, security, attribute-based credentials, hardware security, computer network

*Officially Gergely, but please call me Greg


28 May 2019. Brinda Hampiholi, my first PhD student, defends her thesis at the Radboud University (further info).


How to reach me?

Mostly I work in Nijmegen at the Radboud University, ICIS Digital Security group. Otherwise, you can reach me by any of the e-mail addresses below.

Grants and awards

Journal Publications

  1. W. Lueks, G. Alpár, J.-H. Hoepman, and P. Vullers. Fast Revocation of Attribute-Based Credentials for Both Users and Verifiers. In Journal of Computers & Security 2016.
    link, local copy)
  2. G. Alpár, J.-H. Hoepman, and J. Siljee. The Identity Crisis -- Security, Privacy and Usability Issues in Identity Management. In Journal of Information System Security 2013.

Conference Proceedings Publications


  1. A. Rasool, G. Alpár, J. de Ruiter. State machine inference of QUIC. (arXiv), 2019. (local copy)


  1. W. Lueks, B. Hampiholi, G. Alpár, C. Troncoso. Tandem: Securing Keys by Using a Central Server While Preserving Privacy. (arXiv), 2018. (local copy)
  2. E. Roubtsova, S. Roubtsov, G. Alpár. Presence Patterns and Privacy Analysis. BMSD 2018, pp 298-307, LNBIP 319, Springer, 2018. (local copy)


  1. B. Hampiholi, G. Alpár. Privacy-preserving webshopping with attributes. IEEE Symposium on Privacy-Aware Computing (IEEE PAC 2017), Washington DC, USA, 2017. (local copy)
  2. G. Alpár, F. van den Broek, B. Hampiholi, B. Jacobs, W. Lueks, S. Ringers. IRMA: practical, decentralized and privacy-friendly identity management using smartphones. 10th Workshop on Hot Topics in Privacy Enhancing Technologies (HotPETs 2017), Minneapolis, USA, 2017. (local copy)


  1. G. Alpár, L. Batina, L. Batten, V. Moonsamy, A. Krasnova, A. Guellier, and I. Natgunanathan. New Directions in IoT Privacy Using Attribute-Based Authentication–Position Paper. Proceedings of the 1st ACM Malicious Software and Hardware in Internet of Things Workshop (MAL-IoT16), Italy, 2016. (to appear, local copy)


  1. Brinda Hampiholi, Gergely Alpár, Fabian van den Broek and Bart Jacobs. Towards practical Attribute-Based Signatures. Proceedings of the Fifth International Conference on Security, Privacy, and Applied Cryptography Engineering (SPACE 2015), Jaipur, India, October 3-7, 2015. (link and local copy)
  2. Wouter Lueks, Gergely Alpár, Jaap-Henk Hoepman, and Pim Vullers. Fast Revocation of Attribute-Based Credentials for Both Users and Verifiers. In Proceedings of the IFIP International Information Security and Privacy Conference (IFIP SEC 2015), Hamburg, May 26-28, 2015.
    The extended version of the paper is available in the IACR ePrint Archive, link)


  1. Merel Koning, Paulan Korenhof, Gergely Alpár and Jaap-Henk Hoepman. The ABC of ABC: an analysis of attribute-based credentials in the light of data protection, privacy and identity. In Proceedings of the 10th International Conference on Internet, Law & Politics (IDP 2014): A decade of transformations, pages 357-374, Barcelona, July 3-4, 2014. (link to pdf, 196kB)
    The paper was also presented at the 7th Workshop on Hot Topics in Privacy Enhancing Technologies (HotPETS 2014, link)


  1. Gergely Alpár and Jaap-Henk Hoepman. A Secure Channel for Attribute-based Credentials [Short paper]. In Proceedings of the 2013 ACM Workshop on Digital Identity Management (DIM 2013), pages 13-18, Berlin, November 8, 2013. (link to pdf, 130kB)
  2. Gergely Alpár and Maarten H. Everts. Mobile Devices to the Identity Rescue. In Proceedings of the IFIP Summer School, Nijmegen, The Netherlands, June, 2013. (link to pdf, 315kB)
  3. Kostas Papagiannopoulos, Gergely Alpár, and Wouter Lueks. Desigated Attribute Proofs with the Camenish–Lysyanskaya Signature. In 34th WIC Symposium on Information Theory, 2013. (link to paper, 309kB, link to poster, 146kB)
  4. Manu Drijvers, Pedro Luz, Gergely Alpár and Wouter Lueks. Ad Hoc Voting on Mobile Devices. In 34th WIC Symposium on Information Theory, 2013. (link to paper, 660kB, link to poster, 123kB)
  5. Gergely Alpár and Bart Jacobs. Credential Design in Attribute-Based Identity Management. In Ronald Leenes and Eleni Kosta, editors, Bridging distances in technology and regulation, pages 189-204, 3rd TILTing Perspectives Conference, Tilburg, NL, April 25-26, 2013. (link to pdf, 632kB)
  6. Gergely Alpár, Jaap-Henk Hoepman, Wouter Lueks. An Attack Against Fixed Value Discrete Logarithm Representations. Cryptology ePrint Archive: Report 2013/120. (link)
  7. Pim Vullers and Gergely Alpár. Efficient Selective Disclosure on Smart Cards Using Idemix. In Simone Fischer-Hübner, Elisabeth de Leeuw, and Chris Mitchell editors, Policies and Research in Identity Management (IDMAN), 3rd IFIP WG 11.6 Working Conference, London, UK, IFIP AICT 396, pages 53–67. Springer, 2013. (link to pdf, 329kB)


  1. Gergely Alpár, Lejla Batina, Wouter Lueks. Designated Attribute-Based Proofs for RFID Applications, In Jaap-Henk Hoepman and Ingrid Verbauwhede, editors, RFID Security and Privacy (RFIDsec), LNCS 7739, Nijmegen, The Netherlands, pages 59–75. Springer, 2012. 2012. (link to pdf, 207kB)
  2. Gergely Alpár, Lejla Batina, Roel Verdult. Using NFC Phones for Proving Credentials, PILATES 2012, LNCS 7201, Kaiserslautern, Germany, 2012. (link to pdf, 180kB)


  1. Gergely Alpár, Jaap-Henk Hoepman. Avoiding Man-in-the-Middle Attacks When Verifying Public Terminals. In Proceedings of IFIP Summer School, Trento, Italy, (IFIP AICT 375 proceedings), 2011. (link to pdf, 279kB)
  2. Gergely Alpár, Jaap-Henk Hoepman, Johanneke Siljee. The Identity Crisis. Security, Privacy and Usability Issues in Identity Management (link)


2019 Spring

2018 Autumn

2018 Spring

2017 Autumn

2017 Spring

2016 Autumn

2016 Spring

2015 Autumn

2015 Spring

2014 Autumn

2013 Spring

2012 Autumn

Students and supervision

PhD Students

PhD committees

Bachelor and master students

PhD Project



  1. Symposium: The Bermuda Triangle of Identity Technologies. January 15. Organiser (flyer).


  1. ABC Technology Workshop at the IFIP Summer School 2013. Organiser. (link)
  2. Research and development at the IRMA (I Reveal My Attributes) pilot project: Attribute-based credentials in practice. (link)
  3. CYRCLE Crypto Club. Organiser. (link)
  4. Member researcher at the PI.lab - Privacy & Identity Lab interdisciplinary research. (link)


  1. RFIDSec 2012, Nijmegen, The Netherlands. Webmaster and a member of the Organizing committee. (link)

Talks, events






Older tutorials, presentations

  1. Anonymous Credentials @ Collis, 2011 (link)
  2. Zero-Knowledge Proofs in Anonymous Credential Systems @ Radboud University, Digital Security Group, 2011 (link)

Popularising technologies

  1. Gergely Alpár. The Future Identity Card. P&I lab -- 4 years later, December 2015. (book chapter, a draft version is available online)
  2. Try the IRMA Android app to get a feeling what attribute-based credentials are. You can read much more about the background on the IRMA page.












Recommended links

Last modified: 17 March 2019