Research

• Cryptology and Information Security: presently my main field of interest, in particular RSA cryptanalysis, applications of hash collisions, relations to number theory, identity management, traitor tracing, lattice based cryptology.
• Number theory: my original field of interest, in particular computational number theory, Diophantine equations, the abc-conjecture and the 3n+1-conjecture.

PhD students

• Ellen Jochemsz
  Cryptanalysis of RSA variants using small roots of polynomials, TU Eindhoven.
  Ellen defended her PhD thesis on October 4, 2007. Henk van Tilborg was promotor, I was co-promotor.
  
  download Ellen's PhD thesis (pdf, about 900 KB).
  
  The TU/e weekly newspaper Cursor interviewed Ellen (in Dutch).
• Marc Stevens
  Attacks on Hash Functions and Applications, University of Leiden.
  Marc defended his PhD thesis on June 19, 2012. Ronald Cramer and Arjen Lenstra were promotores, I was co-promotor.
  
  download Marc's PhD thesis (pdf, about 5.1 MB).
• Meilof Veeningen
  Objective Privacy - Understanding the privacy impact of information exchange, TU Eindhoven.
  Meilof defended his PhD Thesis on June 10, 2014. Sandro Etalle was promotor, Nicola Zannone and I were co-promotores.
  
  download Meilof's PhD thesis (pdf, about 5.7 MB).
  
  Meilof worked on the Mobiman project (Identity Management on Mobile Devices).
  
• Jan-Jaap Oosterwijk
  Jan-Jaap worked on the Crest project, supervised by Boris Škorić and me.
• Thijs Laarhoven
  Search problems in cryptography: From fingerprinting to lattice sieving, TU Eindhoven.
  Thijs defended his PhD thesis on February 16, 2016, and was awarded the doctor's degree Cum Laude. Tanja Lange was promotor, Boris Škorić and I were co-promotores.
  
  download Thijs's PhD thesis (pdf, about 8.5 MB).
  
  Thijs worked on the SLaBaC project (Security of Lattice Based Cryptography), and "on the side" did a lot of work related to the Crest project as well.
• Manos Doulgerakis (Mανoς Δoυλγερακις)
  Lattice cryptanalysis
  Defense: September 9, 2022.

bibliography

project involvement

• CREST - Collusion RESistant Tracing
• MobiMan - Identity Management on Mobile Devices
• SLaBaC - Security of Lattice Based Cryptosystems

talks

• October 24, 2013: "Het geheim van goede koffie", OMO lerarendag, Den Bosch.
• August 30, 2013: "Het 3n+1-vermoeden", Vakantiecursus, CWI Amsterdam..
• August 23, 2013: "Het 3n+1-vermoeden", Vakantiecursus, TU Eindhoven.
• June 19, 2013: "Het 3n+1-vermoeden", 25e InterTU-Studiedag, 3TU.AMI, Eindhoven.
• April 10, 2013: "De publieke geheimen van Alice en Bob", Fontys Wiskunde Event, Tilburg.

• June 20, 2012: "The Danger of Broken Crypto", Leonardo Da Vinci Meeting, TU/e.
• January 12, 2012: "Hard Lattice Problems", Indo-US Workshop "Mathematical and Statistical Aspects of Cryptography", Indian Statistical Institute, Kolkata, India.

• March 23, 2011: "De uitdaging van informatiebeveiliging", Studium Generale, TU Eindhoven.

• September 4, 2010: "Hoe je het cryptosysteem RSA soms kunt kraken", Vakantiecursus, TU Eindhoven.
• August 28, 2010: "Hoe je het cryptosysteem RSA soms kunt kraken", Vakantiecursus, CWI Amsterdam.

• November 25, 2009: "MD5 Considered Harmful Today", Securiosity, Nationaal Informatica Congres, Nijmegen.
• September 14, 2009: "The rogue CA attack - On the insecurity of MD5", Ecrypt II Workshop, Leuven.
• May 14, 2009: (met Marc Stevens): "Botsingen voor hashfuncties en de veiligheid van certificaten", Getronics, Zoetermeer.
• May 13, 2009: "Botsingen voor hashfuncties en de veiligheid van certificaten", GridForum Bedrijvendag, Amersfoort.
• April 24, 2009: "MD5 Considered Harmful Today", EiPSI First Anniversary, Eindhoven.
• April 6, 2009: "Alles onder controle op het Internet?", Veersymposium, Eindhoven.
• February 12, 2009: "Hashbotsingen - de stand van zaken", GovCert, Den Haag.
• February 6, 2009: "Voorspellen met een PlayStation3", Nederlandse Wiskunde Dagen, Noordwijkerhout.
• February 5, 2009: "Botsingen voor hashfuncties en de veiligheid van certificaten - de stand van zaken", GBO Overheid, Den Haag.
• January 7, 2009: "MD5 Considered Harmful Today", EiPSI Seminar, Eindhoven.

• December 12, 2008: "Hashfuncties: een wiskundige knoeiboel", TIASNimbas MSIT/MISM Diplomauitreiking, Eindhoven.
• May 20, 2008: "Hash-botsingen, de stand van zaken", NL-DEX 10, Digital Experts Exchange KLPD, Driebergen.

• March 15, 2007: "Hash collisions: an update", LogicaCMG SIG Security, Eindhoven.
• January 25, 2007: "Inleiding Cryptologie", dotNed, Utrecht.

• November 3, 2006: "Hash Collisions: A Crisis in Cryptography?", ITW Symposium, Delft.
• September 14, 2006: "Hash Collisions: A Crisis in Cryptography?", GOVCERT.NL Symposium, Scheveningen.
• June 13, 2006: "Recent Developments in Cryptanalysis of Hash Functions", with Arjen Lenstra, I4 Forum, Antwerp

• July 8, 2005: "Applications of Hash Collisions to Public Keys", Macquarie University, Sydney.
• July 5, 2005: "On the possibility of constructing meaningful hash collisions for public keys",
• June 29, 2005: "Partial Key Exposure Attacks on RSA", Macquarie University, Sydney.
• May 31, 2005: "Hash functies onder vuur", LogicaCMG, Amstelveen
• April 8, 2005: "Applications of Hash Collisions", EIDMA Cryptography Working Group, Utrecht

• October 28, 2004: "Internet-beveiliging", Congres "IT met het oog op de toekomst", Apeldoorn-IT
• April 17, 2004: "Cycles for the 3n+1-problem", Dutch-Belgian Mathematical Conference, Tilburg University
• April 2, 2004: "Partial Key Exposure Attacks on RSA", EIDMA Cryptography Working Group, Utrecht

• April 9, 2003: "The ICZ-attack on OpenPGP", Combinatorial Theory Seminar, TU Eindhoven
• February 5, 2003: "Cycles for the 3n+1-problem", Combinatorial Theory Seminar, TU Eindhoven

• October 4, 2002: "Weak RSA Key Pairs", EIDMA Cryptography Working Group, Utrecht

organisational

• co-organizer of the 3TU.AMI Opening Symposium, April 15, 2010
• co-organizer of the Lorentz Center Workshop Hash functions in cryptology: theory and practice, Leiden, June 2-6, 2008
• I have been a work group leader in Ecrypt-Aztec, co-organizing a number of "research retreats".
• As of September 1, 2011, the job of mediator (vertrouwenspersoon) for the PhD students in the TU/e Department of Mathematics has been taken up by Jacques Resing.

awards

• Crypto 2009 Best Paper Award for the paper "Short chosen-prefix collisions for MD5 and the creation of a rogue CA certificate" by Marc Stevens, Alex Sotirov, Jacob Appelbaum, Arjen Lenstra, David Molnar, Dag Arne Osvik and me.
• The "Rogue CA-attack" made it to number 1 of the Top Ten Web Hacking Techniques of 2009.

Erdös number

h-index