Jens Groth

Jens Groth
Department of Computer Science, UCL     
Gower Street
London WC1E 6BT
United Kingdom

Office: 6.21a (door phone: 33666)
E-mail: j.groth@ucl.ac.uk (e-mail best way to reach me)
Phone: +44 20 7679 3666
Fax: +44 20 7387 1397
Skype: jensois

Group

Working with me are Research Associates Essam Ghadafi, Sune Jakobsen and PhD students Jonathan Bootle, Andrea Cerulli, Pyrros Chaidos and Mary Maller. We are part of UCL's Information Security Group and UCL's Academic Centre of Excellence in Cyber Security Research.

Click on openings for information on open positions and other opportunities to come and work with us. We are currently looking for a Research Associate (Post-Doc) with a deadline for applications on November 6, 2016.

Publications

Jonathan Bootle, Andrea Cerulli, Pyrros Chaidos, Essam Ghadafi and Jens Groth: Foundations of Fully Dynamic Group Signatures. Applied Cryptography and Network Security - ACNS 2016, LNCS 9696, pages 117-136.
IACR ePrint   

Jens Groth: On the Size of Pairing-based Non-interactive Arguments. Advances in Cryptology - EUROCRYPT 2016, LNCS 9666, pages 305-326.
IACR ePrint    slides

Jonathan Bootle, Andrea Cerulli, Pyrros Chaidos, Jens Groth and Christophe Petit: Efficient Zero-Knowledge Arguments for Arithmetic Circuits in the Discrete Log Setting. Advances in Cryptology - EUROCRYPT 2016, LNCS 9666, pages 327-357.
IACR ePrint    slides

Masayuki Abe, Georg Fuchsbauer, Jens Groth, Kristiyan Haralambiev and Miyako Ohkubo: Structure-Preserving Signatures and Commitments to Group Elements. Journal of Cryptology 29(2): pages 363-421, 2016. (appeared earlier in CRYPTO 2011)

Jens Groth: Efficient Fully Structure-Preserving Signatures for Large Messages. Advances in Cryptology - ASIACRYPT 2015, LNCS 9452, pages 239-259.
IACR ePrint    slides

Craig Gentry, Jens Groth, Yuval Ishai, Chris Peikert, Amit Sahai and Adam Smith: Using Fully Homomorphic Hybrid Encryption to Minimize Non-interative Zero-Knowledge Proofs. Journal of Cryptology 28(4), pages 820-843, 2015.
pdf

Jonathan Bootle, Andrea Cerulli, Pyrros Chaidos, Essam Ghadafi, Jens Groth and Christophe Petit: Short Accountable Ring Signatures Based on DDH. Computer Security - ESORICS 2015, LNCS 9326, pages 243-265.
IACR ePrint   

Jens Groth and Markulf Kohlweiss: One-out-of-Many Proofs: Or How to Leak a Secret and Spend a Coin. Advances in Cryptology - EUROCRYPT 2015, LNCS 9057, pages 253-280.
IACR ePrint    slides

Pyrros Chaidos and Jens Groth: Making Sigma-Protocols Non-interactive without Random Oracles. Practice and Theory in Public Key Cryptography - PKC 2015, LNCS 9020, pages 650-670.

George Danezis, CÚdric Fournet, Jens Groth and Markulf Kohlweiss: Square Span Programs with Applications to Succinct NIZK Arguments. Advances in Cryptology -- ASIACRYPT 2014, LNCS 8873, pages 532-550.
IACR ePrint    slides

Masayuki Abe, Jens Groth, Miyako Ohkubo and Takeya Tango: Converting Cryptographic Schemes from Symmetric to Asymmetric Bilinear Groups. Advances in Cryptology -- CRYPTO 2014, LNCS 8616, pages 241-260.

Masayuki Abe, Jens Groth, Miyako Ohkubo and Mehdi Tibouchi: Structure-Preserving Signatures from Type II Pairings. Advances in Cryptology -- CRYPTO 2014, LNCS 8616, pages 390-407.
IACR ePrint    slides

Jens Groth and Rafail Ostrovsky: Cryptography in the Multi-string Model. Journal of Cryptology, vol. 27(3), pages 506-543, 2014.
pdf   

Alex Escala and Jens Groth: Fine-Tuning Groth-Sahai Proofs. Practice and Theory in Public Key Cryptography - PKC 2014, LNCS 8383, pages 630-649.
IACR ePrint    slides

Masayuki Abe, Jens Groth, Miyako Ohkubo and Mehdi Tibouchi: Unified, Minimal and Selectively Randomizable Structure-Preserving Signatures. Theory of Cryptography Conference - TCC 2014, LNCS 8349, pages 688-712.
IACR ePrint    slides

Stephanie Bayer and Jens Groth: Zero-knowledge Argument for Polynomial Evaluation with Application to Blacklists. Advances in Cryptology - EUROCRYPT 2013, LNCS 7881, pages 646-663.
pdf    slides

Jens Groth and Amit Sahai: Efficient Noninteractive Proof Systems for Bilinear Groups. SIAM Journal on Computing, vol. 41(5), pages 1193-1232.
pdf    slides    (appeared earlier in EUROCRYPT 2008)

Jens Groth, Rafail Ostrovsky and Amit Sahai: New Techniques for Noninteractive Zero-Knowledge. Journal of the ACM, vol. 59(3), pages 11:1-11:35, 2012.
pdf    (appeared earlier in EUROCRYPT 2006 and CRYPTO 2006)

Stephanie Bayer and Jens Groth: Efficient Zero-Knowledge Argument for Correctness of a Shuffle. Advances in Cryptology - EUROCRYPT 2012, LNCS 7237, 263-280.
pdf    slides    (full paper)

Jens Groth: Efficient Zero-Knowledge Arguments from Two-Tiered Homomorphic Commitments. Advances in Cryptology - ASIACRYPT 2011, LNCS 7073, 431-448.
pdf    slides    (full paper)

Masayuki Abe, Jens Groth and Miyako Ohkubo: Separating Short Structure Preserving Signatures from Non-Interactive Assumptions. Advances in Cryptology - ASIACRYPT 2011, LNCS 7073, 628-646.

Masayuki Abe, Jens Groth, Kristiyan Haralambiev and Miyako Ohkubo: Optimal Structure-Preserving Signatures in Asymmetric Bilinear Groups. Advances in Cryptology - CRYPTO 2011, LNCS 6841, pages 649-666.
pdf    slides     (full paper)

Jens Groth: Short Non-interactive Zero-Knowledge Proofs. Advances in Cryptology - ASIACRYPT 2010, LNCS 6477, pages 341-358.
pdf    slides    (full paper)

Jens Groth: Short Pairing-Based Non-interactive Zero-Knowledge Arguments. Advances in Cryptology - ASIACRYPT 2010, LNCS 6477, pages 321-340.
pdf    slides    (full paper)

Jens Groth: A Verifiable Secret Shuffle of Homomorphic Encryptions. Journal of Cryptology, vol. 23(4), pages 546-579, 2010.
pdf    slides    (appeared earlier in PKC 2003)

Jens Groth: Homomorphic Trapdoor Commitments to Group Elements.
pdf    (manuscript)
Merged paper Masayuki Abe, Georg Fuchsbauer, Jens Groth, Kristiyan Haralambiev and Miyako Ohkubo: Structure-Preserving Signatures and Commitments to Group Elements. Advances in Cryptology - CRYPTO 2010, LNCS 6223, pages 209-236. (see journal version above)

Jens Groth, Aggelos Kiayias and Helger Lipmaa: Multi-Query Computationally-Private Information Retrieval with Constant Communication Rate. Practice and Theory in Public Key Cryptography - PKC 2010, LNCS 6056, pages 107-123.
pdf    slides

Jens Groth: Linear Algebra with Sub-linear Size Zero-Knowledge Arguments. Advances in Cryptology - CRYPTO 2009, LNCS 5677, pages 192-208.
pdf    slides    more slides    (full paper)

Jens Groth and Yuval Ishai: Sub-linear Zero-Knowledge Argument for Correctness of a Shuffle. Advances in Cryptology - EUROCRYPT 2008, LNCS 4965, pages 379-396.
pdf    slides    (full paper)

Jens Groth and Steve Lu: A Non-interactive Shuffle with Pairing Based Verifiability. Advances in Cryptology - ASIACRYPT 2007, LNCS 4833, pages 51-67.
pdf    slides

Jens Groth: Fully Anonymous Group Signatures without Random Oracles. Advances in Cryptology - ASIACRYPT 2007, LNCS 4833, pages 164-180.
pdf    slides    (full paper)

Jens Groth and Rafail Ostrovsky: Cryptography in the Multi-string Model. Advances in Cryptology - CRYPTO 2007, LNCS 4622, pages 323-341.
(see journal version above)

Nishanth Chandran, Jens Groth and Amit Sahai: Ring Signatures of Sub-linear Size without Random Oracles. International Colloquium on Automata, Languages and Programming - ICALP 2007, LNCS 4596, pages 423-434.
pdf    slides

Jens Groth and Amit Sahai: Efficient Non-interactive Proof Systems for Bilinear Groups. Advances in Cryptology - EUROCRYPT 2008, LNCS 4965, pages 415-432.
pdf    slides    (see journal version above)

Jens Groth and Steve Lu: Verifiable Shuffle of Large Size Ciphertexts. Practice and Theory in Public Key Cryptography - PKC 2007, LNCS 4450, pages 377-392.
pdf    excel   

Jens Groth: Simulation-sound NIZK Proofs for a Practical Language and Constant Size Group Signatures. Advances in Cryptology - ASIACRYPT 2006, LNCS 4284, pages 444-459.
pdf    slides    (full paper)

Jens Groth, Rafail Ostrovsky and Amit Sahai: Non-interactive Zaps and New Techniques for NIZK. Advances in Cryptology - CRYPTO 2006, LNCS 4117, pages 97-111.
slides    (see journal version above)

Douglas Wikström and Jens Groth: An Adaptively Secure Mix-Net Without Erasures. International Colloquium on Automata, Languages and Programming - ICALP 2006, LNCS 4052, pages 276-287.

Jens Groth, Rafail Ostrovsky and Amit Sahai: Perfect Non-Interactive Zero-Knowledge for NP. Advances in Cryptology - EUROCRYPT 2006, LNCS 4004, pages 338-359.
slides    (see journal version above)

Jens Groth: Non-interactive Zero-Knowledge Arguments for Voting. Applied Cryptography and Network Security - ACNS 2005, LNCS 3531, pages 467-482.
pdf      slides   (full paper)

Jens Groth: Cryptography in Subgroups of Zn*. Theory of Cryptography Conference - TCC 2005, LNCS 3378, pages 50-65.
pdf    slides   (corrected paper)

Jan Camenisch and Jens Groth: Group Signatures: Better Efficiency and New Theoretical Aspects. Security in Communication Networks - SCN 2004, LNCS 3352, pages 120-133.
pdf    (full paper)

Jens Groth: Evaluating Security of Voting Schemes in the Universal Composability Framework. Applied Cryptography and Network Security - ACNS 2004, LNCS 3089, pages 46-60.
pdf    slides    (full paper)

Jens Groth: Rerandomizable and Replayable Adaptive Chosen Ciphertext Attack Secure Cryptosystems. Theory of Cryptography Conference - TCC 2004, LNCS 2951, pages 152-170.
pdf    slides

Jens Groth: Efficient Maximal Privacy in Boardroom Voting and Anonymous Broadcast. Financial Cryptography - FC 2004, LNCS 3110, pages 90-104.
pdf    slides

Ivan Damgård and Jens Groth: Non-interactive and Reusable Non-malleable Commitment Schemes. Symposium on Theory of Computation - STOC 2003, pages 426-437.
pdf   slides    (corrected paper)

Jens Groth: A Verifiable Secret Shuffle of Homomorphic Encryptions. Practice and Theory in Public Key Cryptography - PKC 2003, LNCS 2567, pages 145-160.
(see journal version above)

Ivan Damgård, Jens Groth and Gorm Salomonsen: The Theory and Implementation of an Electronic Voting System. D. Gritzalis (Ed.), Secure Electronic Voting, Kluwer Academic Publishers, 2002, pages 77-99.
pdf

Jens Groth and Gorm Salomonsen: Strong Privacy Protection in Electronic Voting. Invited talk at Trust and Privacy in Digital Business - TrustBus 2001. Full paper available as BRICS technical report RS-04-23.

Program Committees

ACNS 2006, EUROCRYPT 2007, PKC 2008, TCC 2008, SCN 2008, TCC 2009, Pairing 2009, CRYPTO 2009, ASIACRYPT 2009, TCC 2010, AFRICACRYPT 2011, VoteID 2011, ASIACRYPT 2011, EUROCRYPT 2012, PKC 2012, CRYPTO 2012, EUROCRYPT 2013, PKC 2014, TCC 2014, CT-RSA 2014, CT-RSA 2015, EUROCRYPT 2015, VoteID 2015, ASIACRYPT 2015, IMA Cryptography and Coding 2015, ACNS 2016, CRYPTO 2016, ASIACRYPT 2016, PKC 2017, AFRICACRYPT 2017.

Open access pledge

I believe in making research publicly and freely available to the world. I have made the following pledge on Research Without Walls:
Effective 1/21/2012, I will assist in the peer review process (as a reviewer, board/committee member, chair, editor, etc.) only for conferences, journals, and other publication venues that make all accepted publications available to the public for free via the web within 3 years of publication.

I want to share a simple strategy to make a conference de facto open access. Many conferences publish proceedings in Springer's Lecture Notes in Computer Science series. Springer's copyright form allows authors to make an online version of their paper available on their homepage or in an institutional repository. So if you are a program chair, you can make it a requirement in the call for papers that authors exercise this right. After decisions have been made on which papers to accept you can then collect the links from the authors. As an example, all the papers accepted to IMACC 2015 are available online here.

Curriculum Vitae

pdf

How to pronounce my name

English speakers can say Yens Grot. This captures the pronounciation of my first name quite well. Unfortunately, the Danish "o"-sound does not have an English equivalent. If you speak another language I suggest using that language's "o" and you may end up pronouncing my surname correctly as well.