Julia Hesse

Publications

2021

• Security analysis of protocols sharing state (via a blockchain, or a PKI) is tricky. Better look at our paper before proving security of your blockchain application!
  On the (Ir)Replaceability of Global Setups, or How (Not) to Use a Global Ledger
  TCC 2021, with Christian Badertscher and Vassilis Zikas
  (Full Version)
• NIKEs with optimal security reductions have remained elusive so far. This paper gives the first one, with trade-offs in key sizes.
  Towards Tight Adaptive Security of Non-Interactive Key Exchange
  TCC 2021, with Dennis Hofheinz, Lisa Kohl and Roman Langrehr
  (Full Version)
• The IRTF is currently standardizing a lightweight PAKE protocol, and we analyze security of its many implementation variants using a new cool and concise modularization technique.
  Security Analysis of CPace
  Asiacrypt 2021, with Michel Abdalla and Björn Haase
  (Full Version)
• We can use fuzzy PAKE to securely connect personal electronics automatically, by turning sensor readings into cryptographic keys!
  FastZIP: Faster and More Secure Zero-Interaction Pairing
  ACM MobiSys 2021, with Mikhail Fomichev, Lars Almon, Timm Lippert, Jun Han and Matthias Hollick
  (Full Version)

2020

• The Universal Composability Framework (Canetti, FOCS 2001) can't handle global setups? Yes it can!
  Universal Composition with Global Subroutines: Capturing Global Setup within plain UC
  TCC 2020, with Christian Badertscher, Ran Canetti, Björn Tackmann and Vassilis Zikas
  (Full Version)
• The beloved fuzzy PAKE goes asymmetric! This is a tricky task with room for improvement. Have a look, get challenged and try to improve upon our protocols!
  Fuzzy Asymmetric Password-Authenticated Key Exchange
  Asiacrypt 2020, with Andreas Erwig, Maximilian Orlt and Siavash Riahi
  (Full Version)
• It is time to revisit the security model for asymmetric PAKE.
  Separating Symmetric and Asymmetric Password-Authenticated Key Exchange
  SCN 2020
  (Full Version)
• Log in with Google and Facebook and Instagram, and rest assured that none of them learn your password.
  PESTO: Proactively Secure Distributed Single Sign-On, how How to Trust a Hacked Server
  IEEE EuroS&P, with Carsten Baum, Tore Kasper Frederiksen, Anja Lehmann and Avishay Yanai
  (Full Version)

2019

• Your blockchain is too slow? This paper introduces protocols and formal foundations for fairly routing off-chain transactions between multiple parties and intermediaries.
  Multi-Party Virtual State Channels
  Eurocrypt 2019, with Stefan Dziembowski, Lisa Eckey, Sebastian Faust and Kristina Hostáková
  (Full Version)
• Identity Management: State of the Art, Challenges and Perspectives
  Privacy and Identity Management 2019, with Tore Kasper Frederiksen, Anja Lehmann and Rafael Torres Moreno
  (SpringerLink)

2018

• Diffie-Hellman key exchange has a suboptimal security reduction with quadratic loss in the number of users. This loss was proven optimal in 2002 (Coron, Eurocrypt). We introduce a simple non-interactive key exchange from Hash Proof System that circumvents this 15 year old bound with only linear loss.
  On Tightly Secure Non-Interactive Key Exchange
  Crypto 2018, with Dennis Hofheinz and Lisa Kohl
  (Full Version)
• Fuzzy PAKE is the first AKE that can handle both low entropy and noisy authentication data.
  Fuzzy Password-Authenticated Key Exchange
  Eurocrypt 2018, with Pierre-Alain Dupont, David Pointcheval, Leonid Reyzin and Sophia Yakoubov
  (Full Version)
• On the relation between two extremely powerful primitives in cryptography.
  Graded Encoding Schemes from Obfuscation
  PKC 2018, with Pooya Farshim, Dennis Hofheinz and Enrique Larraia
  (Full Version)

2016

• Revoking enrolled cryptography is tedious, but sometimes necessary when the underlying groups (e.g., elliptic curves) become outdated and too insecure. Is it possible to increase the security (parameter) of a scheme after it is enrolled? Believe it or not - it is possible!
  Reconfigurable Cryptography: A flexible approach to long-term security
  TCC 2016-A, with Dennis Hofheinz and Andy Rupp
  (Full Version)

2014

• Computations in composite-order groups are slow. We show how to emulate them with prime-order groups, including not only group operations but also complex structures such as pairings or even multilinear maps. Spoiler: this work makes Groth-Sahai proofs in composite-order groups twice as efficient as before.
  Polynomial Spaces: A New Framework for Composite-to-Prime-Order Transformations
  CRYPTO 2014, with Gottfried Herold, Dennis Hofheinz, Carla Ràfols and Andy Rupp
  (Full Version) (Slides)
• Introducing a strong security notion for the Diffie-Hellman key exchange, including feasibility as well as impossibility results.
  Universally Composable Non-Interactive Key Exchange. SCN 2014, with Eduarda S.V. Freire and Dennis Hofheinz
  (Full Version)

Organized Events

• Future of PI: Challenges and Perspectives of Personal Identification, co-located with EuroS&P 2021, Vienna, Austria
• Identity Management: State of the Art, Challenges and Perspectives, at IFIP Summer School on Privacy and Identity Management, 2019, Brugg, Switzerland
• CrossFyre 2019, co-located with Eurocrypt 2019 at TU Darmstadt