Prof. Dr. Alexander May Lehrstuhl für Kryptologie und IT-Sicherheit Horst Görtz Institut für IT-Sicherheit Ruhr-Universität Bochum Universitätsstraße 150 D-44780 Bochum NA 5/73 Tel.: +49 (0)234 32 23261 Fax.: +49 (0)234 32 14430 E-Mail: alex.may(at)ruhr-uni-bochum.de

Consulting Hour:

Do. 14:00

Research Interests

Public-key cryptography Lattice reduction RSA Algorithmic number theory Quantum algorithms Cryptographic protocols

Program Committee

Eurocrypt 2011, 2010, 2007, 2006 Asiacrypt 2007 PKC 2011, 2008, 2006 Africacrypt 2009, 2008 CT-RSA 2011, 2009 Cryptography and Coding 2007 SCC 2010 , 2008 Secrypt 2007, 2006 WeWoRC 2007

Membership

IACR, International Association for Cryptologic Research GI, Gesellschaft für Informatik

Conference Organization

Factoring 2009 September 11+12, Bochum Eurocrypt 2009 April 26-30, Cologne 2. Workshop "Kryptologie in Theorie und Praxis" in Bremen, on September 27, 2007 CLC2006 - Workshop on Codes and Lattices in Cryptography in Darmstadt, on September 25-27, 2006

Survey

Alexander May "Using LLL-Reduction for Solving RSA and Factorization Problems: A Survey" LLL+25 Conference in honour of the 25th birthday of the LLL algorithm, 2007.

Conference Publications

Wilko Henecka, Alexander May, Alexander Meurer "Correcting Errors in RSA Private Keys" In Advances in Cryptology (Crypto 2010), Lecture Notes in Computer Science, Springer-Verlag, 2010. Mathias Herrmann, Alexander May "Maximizing Small Root Bounds by Linearization and Applications to Small Secret Exponent RSA" In Practice and Theory in Public Key Cryptography (PKC 2010), Lecture Notes in Computer Science, Springer-Verlag, 2010. Mathias Herrmann, Alexander May "Attacking Power Generators Using Unravelled Linearization: When Do We Output Too Much?" In Advances in Cryptology (Asiacrypt 2009), Lecture Notes in Computer Science, Springer-Verlag, 2009. Alexander May, Maike Ritzenhofen "Implicit Factoring: On Polynomial Time Factoring Given Only an Implicit Hint" In Practice and Theory in Public Key Cryptography (PKC 2009), Lecture Notes in Computer Science, Springer-Verlag, 2009. Mathias Herrmann, Alexander May "Solving Linear Equations Modulo Divisors: On Factoring Given Any Bits" In Advances in Cryptology (Asiacrypt 2008), Lecture Notes in Computer Science, Springer-Verlag, 2008. Alexander May, Maike Ritzenhofen "Solving Systems of Modular Equations in One Variable: How Many RSA-Encrypted Messages Does Eve Need to Know?" In Practice and Theory in Public Key Cryptography (PKC 2008), Lecture Notes in Computer Science Volume 4939, pages 37-46, Springer-Verlag, 2008. Ellen Jochemz, Alexander May "A Polynomial Time Attack on RSA with Private CRT-Exponents Smaller Than N^0.073" In Advances in Cryptology (Crypto 2007), Lecture Notes in Computer Science, Springer-Verlag, 2007. Ellen Jochemz, Alexander May "A Strategy for Finding Roots of Multivariate Polynomials with New Applications in Attacking RSA Variants" In Advances in Cryptology (Asiacrypt 2006), Lecture Notes in Computer Science, Springer-Verlag, 2006. Daniel Bleichenbacher, Alexander May "New Attacks on RSA with Small Secret CRT-Exponents" In Practice and Theory in Public Key Cryptography (PKC 2006), Lecture Notes in Computer Science, Springer-Verlag, 2006. Johannes Blömer, Alexander May "A Tool Kit for Finding Small Roots of Bivariate Polynomials over the Integers" In Advances in Cryptology (Eurocrypt 2005), Lecture Notes in Computer Science Volume 3494, pages 251-267, Springer-Verlag, 2005. Matthias Ernst, Ellen Jochemsz, Alexander May and Benne de Weger "Partial Key Exposure Attacks on RSA up to Full Size Exponents" In Advances in Cryptology (Eurocrypt 2005), Lecture Notes in Computer Science Volume 3494, pages 371-386, Springer-Verlag, 2005. Alexander May "Computing the RSA Secret Key is Deterministic Polynomial Time Equivalent to Factoring" In Advances in Cryptology (Crypto 2004), Lecture Notes in Computer Science Volume 3152, pages 213-219, Springer Verlag, 2004. Alexander May "Secret Exponent Attacks on RSA-type Schemes with Moduli N=p^rq" In Practice and Theory in Public Key Cryptography (PKC 2004), Lecture Notes in Computer Science Volume 2947, pages 218-230, Springer-Verlag, 2004. Johannes Blömer, Alexander May "A Generalized Wiener Attack on RSA" In Practice and Theory in Public Key Cryptography (PKC 2004), Lecture Notes in Computer Science Volume 2947, pages 1-13, Springer-Verlag, 2004. Johannes Blömer, Alexander May "New Partial Key Exposure Attacks on RSA" In Advances in Cryptology (Crypto 2003), Lecture Notes in Computer Science Volume 2729, pages 27-43, Springer Verlag, 2003. Alexander May "Cryptanalysis of Unbalanced RSA with Small CRT-Exponent" In Advances in Cryptology (Crypto 2002), Lecture Notes in Computer Science Volume 2442, pages 242-256, Springer Verlag, 2002. Johannes Blömer, Alexander May "Key Revocation with Interval Cover Families" In Selected Areas in Cryptography (SAC 2001), Lecture Notes in Computer Science Volume 2259, pages 325-341, Springer-Verlag, 2001. Alexander May, Joseph H. Silverman "Dimension Reduction Methods for Convolution Modular Lattices" In Cryptography and Lattice Conference (CaLC 2001), Lecture Notes in Computer Science Volume 2146, pages 110-125, Springer-Verlag, 2001. Johannes Blömer, Alexander May "Low Secret Exponent RSA Revisited" In Cryptography and Lattice Conference (CaLC 2001), Lecture Notes in Computer Science Volume 2146, pages 4-19, Springer-Verlag, 2001. Alexander May "Cryptanalysis of NTRU-107" (Note: Preprint).

Journal Publications

Jean-Sébastien Coron, Alexander May "Deterministic Polynomial Time Equivalent of Computing the RSA Secret Key and Factoring" Journal of Cryptology, 2006 Johannes Buchmann, Alexander May, Ulrich Vollmer "Perspectives for Cryptographic Long-Term Security" Communications of the ACM, Vol. 94(9), 2006 Johannes Buchmann, Erik Dahmen, Alexander May, Ulrich Vollmer "Krypto 2020" KES - The Information Security Journal, Nr 5, 2006

PhD Thesis

"New RSA Vulnerabilities Using Lattice Reduction Methods", University of Paderborn, 2003.

Diploma Thesis

"Auf Polynomgleichungen basierende Public-Key-Kryptosysteme", University of Frankfurt/Main, 1999

Invited Talks

Workshop on Mathematical Cryptology WMC 2008, Santander, Oct 2008 Central European Conference on Cryptography CECC 2008, Graz, July 2008 LLL+25 Conference in honour of the 25th birthday of the LLL algorithm, Caen, June 2007 American Mathematical Society Sectional Meeting, Stevens Institute, New Jersey, April 2007 Workshop on Cryptography: Underlying Mathematics, Provability and Foundations, Fields Institute, Toronto, November 2006 Workshop: Number Theory and Cryptography - Open Problems, IPAM, University of California, October 2006 CLC2006 - Workshop on Codes and Lattices in Cryptography, Darmstadt, September 2006 Crypto seminar, Universite du Luxembourg, Juni 2005 Cryptologie & Algorithmique En Normandie (CAEN 2005) , Caen, Mai 2005 ECRYPT Cryptanalysis Summer School, Samos, Greece, Mai 2005 Pure Mathematics Seminars, Royal Holloway, University of London , Februar 2005 Séminaire Cryptographie, Codes et Algorithmique , ENSTA Paris, November 2004 Séminaire de Cryptographie, Université de Caen, November 2004 The 8th Workshop on Elliptic Curve Cryptography (ECC 2004) , Ruhr-Universität Bochum, September 2004 EIDMA Seminar Combinatorial Theory, Technische Universiteit Eindhoven, August 2004 SPACES Seminaire , Nancy, April 2004 Cryptologie & Algorithmique En Normandie (CAEN 2003) , Caen, Juni 2003

Awards

Best paper award PKC 2009 for "Implicit Factoring: On Polynomial Time Factoring Given Only an Implicit Hint" with Maike Ritzenhofen Best paper award PKC 2006 for "New Attacks on RSA with Small Secret CRT-Exponents" with Daniel Bleichenbacher Beste Lehre SS 2007, Preis der Fachschaft TU Darmstadt Beste Lehre WS05/06, Preis der Fachschaft TU Darmstadt Weierstraß-Preis 2004 der Universität Paderborn