Greg Alpar is assistant professor at the Open Universiteit and visiting researcher at the Radboud University's Digital Security group.

Previously I was a post-doctorate lecturer and researcher at RU's Comuter Science 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.

Personal website:


Journal Publications

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.

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


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


W. Lueks, B. Hampiholi, G. Alpár, C. Troncoso. Tandem: Securing Keys by Using a Central Server While Preserving Privacy. (arXiv), 2018. (local copy)

E. Roubtsova, S. Roubtsov, G. Alpár. Presence Patterns and Privacy Analysis. BMSD 2018, pp 298-307, LNBIP 319, Springer, 2018. (local copy)


B. Hampiholi, G. Alpár. Privacy-preserving webshopping with attributes. IEEE Symposium on Privacy-Aware Computing (IEEE PAC 2017), Washington DC, USA, 2017.

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.


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)


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)

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)


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)


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)

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)

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)

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)

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)

Gergely Alpár, Jaap-Henk Hoepman, Wouter Lueks. An Attack Against Fixed Value Discrete Logarithm Representations. Cryptology ePrint Archive: Report 2013/120. (link)

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)


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)

Gergely Alpár, Lejla Batina, Roel Verdult. Using NFC Phones for Proving Credentials, PILATES 2012, LNCS 7201, Kaiserslautern, Germany, 2012. (link to pdf, 180kB)


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)

Gergely Alpár, Jaap-Henk Hoepman, Johanneke Siljee. The Identity Crisis. Security, Privacy and Usability Issues in Identity Management (link)



Open Maths at the Brave New Learning ELIG Conference, Comenius Teachers talk session. February 11, 2019.


Open Maths at the Open University (November 24, 2018, Workshop Informatica studiedag organised by the Department of Computer Science of the Open University, The Netherlands

Open Maths (November 8, 2018, Workshop Skills for Jobs in the Digital Era organised by the Digital Enlightenment Forum

Open Maths Course 2018 (September 10, 2018, Thalia lunch colloquium organised by the Study Association Thalia

Authentication with Privacy and Security: the maths behind attribute-based credentials (August 25 and September 1, 2019, Vakantiecursus, Platform Wiskunde Nederland). The syllabus and the problems (with solutions) can be downloaded.


The Alphabet of ABCs (April 4, 2017, OUrsi talk at the Open Universiteit)


Privacy and the P&I Course (January 29, 2016, lunch colloquium at our Digital Security group)

Privacy with Attributes, invited talk (January 19, 2016, Software Improvement Group)


IRMA: Attribute-Based Identity Management Using Smart Cards (June 4, 2015, Šibenik, Croatia: Summer school on real-world crypto and privacy, invited talk, link)

ABCs in Theory and Practice (June 23, 2015, New York, NY, USA: RFIDsec 2015, invited talk)



2019 Spring

Software Life Cycle (IM0303, 7.5 ec) - lecturer, examinator (link)

Research Preparation (IM0101, 2.5 ec) - teacher (link)

Software Architecture (IM0203, 7.5 ec) - teacher (link)

Open Maths (experimental course) - examinator, teacher (linkyOUlearn link)

2018 Autumn

Research Preparation (IM0101, 2.5 ec) - teacher (link)

Software Engineering (IB3102, 5 ec) - examinator (link)

2018 Spring

Research Preparation (IM0101, 2.5 ec) - teacher (link)

Software Life Cycle (IM0303, 7.5 ec) - lecturer, examinator (link)

2017 Autumn

Software Engineering (T07351, 4.3ec) - lecturer, examinator

Research Preparation (IM0101, 2.5ec) - teacher

2017 Spring

Computer Networking (6ec) - lecturer, coordinator

Software Life Cycle - lecturer, examinator

2016 Autumn

Software Engineering (4.3ec) - lecturer, coordinator

Security and IT (4.3ec) - lecturer

2016 Spring

Computer Networking (6ec) - lecturer

Introduction to Cryptography (6ec) - lecturer

2015 Autumn

Privacy and Identity (3ec) - lecturer; see also my overview lunch colloquium

Calculus en Kansrekening (3ec) - lecturer

Security - TA

2015 Spring

Computer Networks and Distributed Systems (6ec) - lecturer

Cryptography (6ec) - TA and partial lecturer

2014 Autumn

Hardware Security (6ec) - lecturer

Security (6ec) - TA

Calculus en Kansrekening (3ec) - TA

2013 Spring

Introduction to Cryptographic Algorithms and Protocols - TA

2012 Autumn

Security - TA