PENCIL - Workshop on Privacy ENhancing Cryptography In Ledgers

Darmstadt, Germany – May 18, 2019 – in conjunction with EUROCRYPT 2019

Thank you for all the participants and speakers! We are looking forward to seeing you again in the future events!

News and updates

The Workshop

Blockchain and distributed ledger technologies (DLTs) have emerged as one of the most revolutionary developments in recent years, with the goal of eliminating centralized intermediaries and installing distributed trusted services. They facilitate trustworthy trades and exchanges over the Internet, power cryptocurrencies, ensure transparency for documents, and much more.

Although based on cryptographic techniques at their core, the currently deployed DLTs do not address privacy. Indeed, the very idea of a public ledger that stores a verifiable record of transactions at first appears inherently incompatible with the privacy requirements of many potential applications, which handle sensitive data such as trade secrets and personal information. New cryptographic techniques and protocols are therefore needed to protect the data, facilitate these applications, and make DLTs deliver on their promises.

The purpose of the proposed workshop on Privacy-Enhancing Cryptography in Ledgers is to bring together researchers and practitioners working in cryptography, security, and distributed systems from academia and industry, who are interested in cryptographic techniques for improving the privacy of blockchains and their protocols. The main goal is to foster information exchange between attendees from the different areas, to present new developments in cryptographic schemes and protocols, as well as applications and challenges in order to stimulate both use of new cryptographic techniques to improve DLT-based systems as well as future cryptographic research targeting applications in DLT.


08:30-09:00 Registration

08:50-09:00 Welcome

09:00-09:45 Keynote 1: Juan Garay (Texas A&M University) 
"A Consensus Taxonomy in the Blockchain Era"

09:45-10:00 Afgjort – A Semi-Synchronous Finality Layer for Blockchains
  Bernardo Magri (Concordium Blockchain Research Center, Aarhus University)
  Jesper Buus Nielsen (Concordium Blockchain Research Center, Aarhus University)
  Daniel Tschudi (Concordium Blockchain Research Center, Aarhus University)

10:00-10:15 Pixel: Multi-Signatures for Consensus
  Manu Drijvers (DFINITY)
  Sergey Gorbunov (Algorand)
Gregory Neven (DFINITY)
Hoeteck Wee (Algorand)

10:15-10:30 A Framework for Anonymous Lottery-Based Protocols in the
  Proof-of-Stake Setting

  Foteini Baldimtsi (George Mason University) 
  Varun Rajeev Madathil (North Carolina State University)
  Alessandra Scafuro (North Carolina State University)
  Linfeng Zhou (North Carolina State University)

10:30-11:00 Coffee Break  

11:00-11:45 Keynote 2: Mateusz Tilewski (Concordium)
“A tale of a Blockchain Startup: How to survive in a science-based industry”

11:45-12:30 PRIViLEDGE Session
 11:45-12:00 Asymmetric Distributed Trust
  Christian Cachin (University of Bern)
  Björn Tackmann (IBM Research – Zurich)
  Presentation slides
 12:00-12:15 Publicly Verifiable Proofs from Blockchains and the Attacks of
Clones in Proof-of-Stake Blockchains
  Alessandra Scafuro (North Carolina State University)
  Luisa Siniscalchi (University of Salerno)
  Ivan Visconti (University of Salerno)
 12:15-12:30 Timed Signatures and Zero-Knowledge Proofs - Timestamping in the
  Blockchain Era

  Aydin Abadi (University of Edinburgh)
  Michele Ciampi (University of Edinburgh)
  Aggelos Kiayias (University of Edinburgh and IOHK)
  Vassilis Zikas (University of Edinburgh and IOHK)  

12:30-14:00 Lunch  

14:00-14:45 Keynote 3: Jens Groth (DFINITY)
"Why should I believe that?"

14:45-15:00 Fully Homomorphic NIZK and NIWI Proofs
  Prabhanjan Ananth (MIT)
  Apoorvaa Deshpande (Brown University)
  Yael Kalai (MSR and MIT)
  Anna Lysyanskaya (Brown University)

15:00-15:15 Zether: Towards Privacy in a Smart Contract World
  Benedikt Bünz (Stanford University)
  Shashank Agrawal (Visa Research)
  Mahdi Zamani (Visa Research)
  Dan Boneh (Stanford University)

15:15-15:30 Bootstrapping Online Trust: Timeline Activity Proofs
  over Public Ledgers

  Constantin Catalin Dragan (Surrey Centre for Cyber Security,
  University of Surrey, UK)
  Mark Manulis (Surrey Centre for Cyber Security,
  University of Surrey, UK)  

15:30-16:00 Coffee Break  

16:00-16:30 PRIViLEDGE Session
16:00-16:15 On QA-NIZK in the BPK Model
Behzad Abdolmaleki (University of Tartu)
  Helger Lipmaa (University of Tartu)
  Janno Siim (University of Tartu)
  Michal Zajac (Clearmatics)
  16:15-16:30 Verifiable MPC and DLT
  Berry Schoenmakers (TU Eindhoven)
  Toon Segers (TU Eindhoven) 
  Presentation slides

16:30-16:45 Quisquis: A New Design for Anonymous Cryptocurrencies
Prastudy Fauzi (Aarhus University)
  Claudio Orlandi (Aarhus University)
  Sarah Meiklejohn (University College London)
  Rebekah Mercer (Aarhus University)

16:45-17:00 Universally Composable and Privacy-Preserving Audit Logs
  Using Bulletin Board

  Jan Camenisch (DFINITY)
  Manu Drijvers (DFINITY)
  Maria Dubovitskaya (DFINITY)
  Anna Kaplan (Technical University of Munich)

17:00-17:15 Goodbye

Cancelled ZEXE: Enabling Decentralized Private Computation
Sean Bowe (Zcash)
Alessandro Chiesa (UC Berkeley)
Matthew Green (John Hopkins University)
Ian Miers (Cornell Tech)
Pratyush Mishra (UC Berkeley)
Howard Wu (UC Berkeley)
Presentation slides

16:45-17:00 Initial Public Offering (IPO) on Permissioned Blockchain using
  Secure Multiparty Computation
Fabrice Benhamouda (IBM Research)
  Angelo De Caro (IBM Research)
  Shai Halevi (IBM Research)
  Tzipora Halevi (Brooklyn College)
  Charanjit Jutla (IBM Research)
  Yacov Manevich (IBM Research)
  Qi Zhang (IBM Research)
  Presentation slides


Björn Tackmann (, IBM Research – Zurich, Switzerland
Ivan Visconti (, University of Salerno, Italy

Program Committee

Christian Badertscher
University of Edinburgh
Fabrice BenhamoudaIBM Research – Yorktown
Benedikt BünzStanford University
Christian CachinUniversity of Bern
Melissa ChaseMicrosoft Research
Sherman ChowChinese University of Hong Kong
Alexandra Dimitrienko
University of Würzburg
Maria Dubovitskaya
Sebastian FaustTU Darmstadt
Georg FuchsbauerENS Paris
Juan GarayTexas A&M University
Peter GažiIOHK Research
Vincenzo IovinoUniversity of Luxembourg
Aggelos KiayiasUniversity of Edinburgh
Markulf KohlweissUniversity of Edinburgh
Helger LipmaaUniversity of Tartu
Mark ManulisUniversity of Surrey
Ian MiersJohns Hopkins University
Jesper Buus NielsenAarhus University
Andres OjamaaGuardtime AS
Miyako OhkuboNICT
Alessandra ScafuroNorth Carolina State University 
Berry SchoenmakersTU Eindhoven
Björn Tackmann (co-chair)IBM Research – Zurich
Daniele VenturiSapienza University of Rome
Ivan Visconti (co-chair)University of Salerno
Hong-Sheng ZhouVirginia Commonwealth University

Registration and venue

The workshop takes place in connection with the EUROCRYPT 2019 conference. Registration is now open on the EUROCRYPT registration site.

PENCIL workshop takes place in Karo 5 building, TU Darmstadt (Karolinenpl. 5, 64289 Darmstadt, Deutschland).


Call for PAPERS (closed)

The workshop on Privacy-Enhancing Cryptography in Ledgers aims at discussing questions of confidentiality, privacy, scalability, and integrity in the context of distributed ledger technologies and cryptocurrencies. The workshop solicits submissions describing current work addressing decentralized cryptocurrencies and distributed ledger technologies, including cryptographic schemes and techniques, analytical results, work on systems, and/or position papers, with a focus on the area of privacy and confidentiality.

Topics of interest include, but are not limited to

Submissions should be written in English, formatted in single-column letter-sized or A4-sized format, and prepared as a PDF file. Submissions have to include: a title, author names and affiliations, and must not exceed eight pages, including references. Since there will be no proceedings, the eight pages are expected to give a precise idea of what will be presented at the workshop. Additional material such as a more detailed description or presentation slides may be added in an optional appendix. Papers must be submitted electronically.

Abstracts of the presentations will be distributed to the workshop participants. As there will be no proceedings, presenting work at PENCIL does not conflict with prior, concurrent, or subsequent publication of the material in any other conference or journal.

Keynote talks

The program of the workshop will include 3 keynote talks given by

Juan GarayTexas A&M University
Charles HoskinsonIOHK

Planned schedule

Submission server opensJanuary 2, 2019
Paper submission deadlineFebruary 15, 2019, 23:59:59 AoE (was Feb 10)
Notification of acceptanceMarch 18, 2019 (was March 3)
WorkshopMay 18, 2019