I am working in CWI's Cryptology and Information Security Group headed by Ronald Cramer. My research interests include all sorts of theoretic cryptography, but in particular the design and analysis of cryptographic building blocks and multi-party protocols.
The versions that can be downloaded below are mostly extended versions. The published versions for some of these papers are available at the LNCS homepage of Springer, at the ACM homepage, or at the IEEE homepage.
Dennis Hofheinz, John Malone-Lee, and Martijn Stam. Obfuscation for cryptographic purposes. Journal of Cryptology, Springer, to appear (short version in Proc. TCC 2007, LNCS 4392, Springer 2007). pdf
Michael Backes, Dennis Hofheinz, and Dominique Unruh. CoSP : A general framework for computational soundness proofs. Proc. ACM CCS 2009, ACM 2009. pdf
Dennis Hofheinz and Eike Kiltz. The Group of Signed Quadratic Residues and Applications. Proc. CRYPTO 2009, LNCS 5677, Springer 2009. pdf
Mihir Bellare, Dennis Hofheinz, and Scott Yilek. Possibility and impossibility results for encryption and commitment secure under selective opening. Proc. EUROCRYPT 2009, LNCS 5479, pp. 1-35, Springer 2009. pdf
Dennis Hofheinz and Eike Kiltz. Practical Chosen Ciphertext Secure Encryption from Factoring. Proc. EUROCRYPT 2009, LNCS 5479, pp. 313-332, Springer 2009. pdf
Dennis Hofheinz, Jörn Müller-Quade, and Dominique Unruh. Polynomial runtime in simulatability definitions. Journal of Computer Security, 2009 (to appear; short version in Proc. IEEE CSFW 2005). pdf
Seung Geol Choi, Javier Herranz, Dennis Hofheinz, Jung Yeon Hwang, Eike Kiltz, Dong Hoon Lee, and Moti Yung. The Kurosawa-Desmedt key encapsulation mechanism is not chosen-ciphertext secure. Information Processing Letters (to appear).
Dennis Hofheinz and Eike Kiltz. Programmable Hash Functions and Their Applications. Proc. CRYPTO 2008, LNCS 5157, pp. 21-38, Springer 2008. pdf
Ivan Damgård, Dennis Hofheinz, Eike Kiltz, and Rune Thorbek. Public-Key Encryption with Non-interactive Opening. Proc. CT-RSA 2008, LNCS 4964, pp. 239-255, Springer 2008. pdf
Dennis Hofheinz and Dominique Unruh. Towards key-dependent message security in the standard model. Proc. EUROCRYPT 2008, LNCS 4965, pp. 108-126, Springer 2008. pdf
Michael Backes, Markus Dürmuth, Dennis Hofheinz, and Ralf Küsters. Conditional reactive simulatability. International Journal of Information Security 7(2):155-169, 2008 (short version in Proc. ESORICS 2006, LNCS 4189). pdf
Ronald Cramer, Goichiro Hanaoka, Dennis Hofheinz, Hideki Imai, Eike Kiltz, Rafael Pass, abhi shelat, and Vinod Vaikuntanathan. Bounded CCA2-secure encryption. Proc. ASIACRYPT 2007, LNCS 4833, pp. 502-518, Springer 2007. pdf
Dennis Hofheinz and Eike Kiltz. Secure hybrid encryption from weakened key encapsulation. Proc. CRYPTO 2007, LNCS 4622, pp. 553-571, Springer 2007. pdf
Dennis Hofheinz, Jörn Müller-Quade, and Dominique Unruh. Universally composable zero-knowledge arguments and commitments from signature cards. Tatra Mountains Mathematical Publications 37:93-103, 2007 (short version in Proc. MORAVIACRYPT'05). pdf
Dennis Hofheinz and Dominique Unruh. Simulatable security and polynomially bounded concurrent composition. Proc. IEEE S&P 2006, pp. 169-182, IEEE 2006. pdf
Dennis Hofheinz and Jörn Müller-Quade, and Dominique Unruh. On the (im-)possibility of extending coin toss. Proc. EUROCRYPT 2006, LNCS 4004, pp. 504-521, Springer 2006. pdf
Dennis Hofheinz, Jörn Müller-Quade, and Rainer Steinwandt. On modeling IND-CCA security in cryptographic protocols. Tatra Mountains Mathematical Publications 33:83-97, 2006 (short version in Proc. WARTACRYPT'04). pdf
Anja Groch, Dennis Hofheinz, and Rainer Steinwandt. A practical attack on the root problem in braid groups. Contemporary Mathematics 418, pp. 121-131, AMS 2006. pdf
Dennis Hofheinz and Dominique Unruh. An attack on a group-based cryptographic scheme. Contemporary Mathematics 418, pp. 133-140, AMS 2006. pdf
Michael Backes, Dennis Hofheinz, Jörn Müller-Quade, and Dominique Unruh. On fairness in simulatability-based cryptographic systems. Proc. FMSE 2005, pp. 13-22. ACM 2005. pdf
Dennis Hofheinz and Dominique Unruh. On the notion of statistical security in simulatability definitions. Proc. ISC 2005, LNCS 3650, pp. 118-133, Springer 2005. pdf
Dennis Hofheinz and Dominique Unruh. Comparing two notions of simulatability. Proc. TCC 2005, LNCS 3378, pp. 86-103, Springer 2005. pdf
Michael Backes and Dennis Hofheinz. How to break and repair a universally composable signature functionality. Proc. ISC 2004, LNCS 3225, pp. 61-72, Springer 2004. pdf
Dennis Hofheinz and Jörn Müller-Quade. A synchronous model for multi-party computation and the incompleteness of oblivious transfer. Proc. FCS 2004 (LICS'04/ICALP'04 affiliated workshop), TUCS general publications 31, pp. 117-130, 2004. pdf
María Isabel González Vasco, Dennis Hofheinz, Consuelo Martínez, and Rainer Steinwandt. On the security of two public key cryptosystems using non-abelian groups. Designs, Codes and Cryptography 32(1-3):207-216, 2004. pdf
Dennis Hofheinz and Jörn Müller-Quade. Universally composable commitments using random oracles. Proc. TCC 2004, LNCS 2951, pp. 58-76, Springer 2004. pdf
Dennis Hofheinz, Jörn Müller-Quade, and Rainer Steinwandt. Initiator-resilient universally composable key exchange. Proc. ESORICS 2003, LNCS 2808, pp. 61-84, Springer 2003. pdf
Dennis Hofheinz and Rainer Steinwandt. A practical attack on some braid group based cryptographic primitives. Proc. PKC 2003, pp. 187-198, Springer 2002. pdf
Dennis Hofheinz and Rainer Steinwandt. A "differential" attack on Polly Cracker. Proc. IEEE ISIT 2002, p. 211, IEEE 2002. pdf
In the winter 2005 term, I have taught a public key cryptography course at the University of Karlsruhe. Furthermore, I have been teaching assistant for a number of cryptography and algorithms classes, and I have co-organized cryptography seminars.
