Sarah Meiklejohn

Bio

I am a Professor in Cryptography and Security at University College London (UCL) and a Staff Research Scientist at Google. At UCL, I am affiliated with the Information Security Group in the Computer Science department. I am also an Associate Director of the Initiative for Cryptocurrencies and Contracts (IC3).

I received a PhD in Computer Science from the University of California, San Diego under the joint supervision of Mihir Bellare and Stefan Savage. During my PhD, I spent the summers of 2011 and 2013 at MSR Redmond, working in the cryptography group with Melissa Chase. I obtained an Sc.M. in Computer Science from Brown University under the guidance of Anna Lysyanskaya in 2009, and an Sc.B. in Mathematics from Brown in 2008.

Contact

s.meiklejohn [at] ucl [dot] ac [dot] uk

Department of Computer Science
University College London
Gower Street
London WC1E 6BT

Projects

TITANIUM: Tools for the Investigation of Transactions in Underground Markets (May 2017 – May 2020)
Glass Houses: Transparency and Privacy in Information Economies (November 2016 – March 2021)

Supervision

I am not working full-time at UCL, which means I am not taking on any postdocs, PhD students, or interns for now. This means that if you email me asking for such a position I will not respond. Thanks for understanding!

I am fortunate to have worked with the following people in the past:

Maria Corte-Real Santos (PhD student → postdoc at ENS de Lyon)
George Kappos (PhD student → Chainalysis)
Haaroon Yousaf (PhD student → Pometry)
Sarah Azouvi (PhD student → Protocol Labs)
Elizabeth Crites (postdoc → postdoc at University of Edinburgh → Web3 Foundation)
Mustafa Al-Bassam (PhD student → Celestia)
Kruakae Pothong (postdoc → 5Rights Foundation)
Mary Maller (PhD student → Ethereum Foundation)
Sergi Delgado Segura (postdoc → Talaia Labs → Chaincode Labs)
Shehar Bano (postdoc → Facebook)
Patrick McCorry (postdoc → faculty at King's College London → PISA Research → Arbitrum)

Publications

(Click year to show/hide)

2025

[C : NeurIPS]	Privacy Reasoning in Ambiguous Contexts Ren Yi, Octavian Suciu, Adrià Gascón, Sarah Meiklejohn, Eugene Bagdasarian, and Marco Gruteser Annual Conference on Neural Information Processing Systems
[C : CCS]	Founding Zero-Knowledge Proofs of Training on Optimum Vicinity Gefei Tan, Adrià Gascón, Sarah Meiklejohn, Mariana Raykova, Xiao Wang, and Ning Luo ACM Conference on Computer and Communications Security
[C : ICML]	Machine Learning Models Have a Supply Chain Problem Sarah Meiklejohn, Hayden Blauzvern, Mihai Maruseac, Spencer Schrock, Laurent Simon, and Ilia Shumailov International Conference on Machine Learning
[C : Oakland]	Supporting Human Raters with the Detection of Harmful Content Using Large Language Models Kurt Thomas, Patrick Gage Kelley, David Tao, Sarah Meiklejohn, Owen Vallis, Shunwen Tan, Blaž Bratanič, Felipe Tiengo Ferreira, Vijay Kumar Eranti, and Elie Bursztein IEEE Symposium on Security and Privacy

2024

[C : IMC]	Give and Take: An End-to-End Investigation of Giveaway Scam Conversion Rates Enze Liu, George Kappos, Eric Mugnier, Luca Invernizzi, Stefan Savage, David Tao, Kurt Thomas, Geoffrey M. Voelker, and Sarah Meiklejohn Internet Measurement Conference
[C : USENIX Security]	Understanding Help-Seeking and Help-Giving on Social Media for Image-Based Sexual Abuse Miranda Wei, Sunny Consolvo, Patrick Gage Kelley, Tadayoshi Kohno, Tara Matthews, Sarah Meiklejohn, Franziska Roesner, Renee Shelby, Kurt Thomas, and Rebecca Umbach USENIX Security Symposium

2023

[C : Crypto]	Bingo: Adaptivity and Asynchrony in Verifiable Secret Sharing and Distributed Key Generation (slides) Ittai Abraham, Philipp Jovanovic, Sarah Meiklejohn, Mary Maller, and Gilad Stern Crypto
[C : USENIX Security]	ACORN: Input Validation for Secure Aggregation James Bell, Adrià Gascón, Tancrède Lepoint, Baiyu Li, Sarah Meiklejohn, Mariana Raykova, and Cathie Yun USENIX Security Symposium
[C : USENIX Security]	One Server for the Price of Two: Simple and Fast Single-Server Private Information Retrieval Alexandra Henzinger, Matthew M. Hong, Henry Corrigan-Gibbs, Sarah Meiklejohn, and Vinod Vaikuntanathan USENIX Security Symposium (The source code for this project can be found here.)
[C : FC]	Forsage: Anatomy of a Smart-Contract Pyramid Scheme Tyler Kell, Haaroon Yousaf, Sarah Allen, Sarah Meiklejohn, and Ari Juels Financial Cryptography and Data Security (The blog post for this project can be found here.)

2022

[C : USENIX Security]	How to Peel a Million: Validating and Expanding Bitcoin Clusters (slides) George Kappos, Haaroon Yousaf, Rainer Stütz, Sofia Rollet, Bernhard Haslhofer, and Sarah Meiklejohn USENIX Security Symposium
[J : PETS]	SoK: SCT Auditing in Certificate Transparency (slides) Sarah Meiklejohn, Joe DeBlasio, Devon O'Brien, Chris Thompson, Kevin Yeo, and Emily Stark Proceedings on Privacy Enhancing Technologies

2021

[C : PODC]	Reaching Consensus for Asynchronous Distributed Key Generation Gilad Stern, Ittai Abraham, Philipp Jovanovic, Sarah Meiklejohn, Alin Tomescu, and Mary Maller ACM Symposium on Principles of Distributed Computing
[C : Eurocrypt]	Aggregatable Distributed Key Generation Kobi Gurkan, Philipp Jovanovic, Mary Maller, Sarah Meiklejohn, Gilad Stern, and Alin Tomescu Eurocrypt (The blog post for this project can be found here.)
[C : DIS]	Problematising Transparency Through LARP And Deliberation Kruakae Pothong, Larissa Pschetz, Ruth Catlow, and Sarah Meiklejohn Designing Interactive Systems (This paper received an Honorable Mention Award!)
[C : Oakland]	SoK: Hate, Harassment, and the Changing Landscape of Online Abuse Kurt Thomas, Devdatta Akhawe, Michael Bailey, Dan Boneh, Elie Bursztein, Sunny Consolvo, Nicki Dell, Zakir Durumeric, Patrick Gage Kelley, Deepak Kumar, Damon McCoy, Sarah Meiklejohn, Thomas Ristenpart, and Gianluca Stringhini IEEE Symposium on Security and Privacy
[W : WTSC]	Pay to Win: Cheap, Cross-Chain Bribing Attacks on PoW Cryptocurrencies Aljosha Judmayer, Nicholas Stifter, Alexei Zamyatin, Itay Tsabary, Ittay Eyal, Peter Gaži, Sarah Meiklejohn and Edgar Weippl The Fifth Workshop on Trusted Smart Contracts
[W : WTSC]	SoK: Algorithmic Incentive Manipulation Attacks on Permissionless PoW Cryptocurrencies Aljosha Judmayer, Nicholas Stifter, Alexei Zamyatin, Itay Tsabary, Ittay Eyal, Peter Gaži, Sarah Meiklejohn and Edgar Weippl The Fifth Workshop on Trusted Smart Contracts
[C : FC]	An Empirical Analysis of Privacy in the Lightning Network George Kappos, Haaroon Yousaf, Ania M. Piotrowska, Sanket Kanjalkar, Sergi Delgado-Segura, Andrew Miller, and Sarah Meiklejohn Financial Cryptography and Data Security

2020

[M : Brookings]	Design Choices for Central Bank Digital Currency: Policy and Technical Considerations Sarah Allen, Srdjan Čapkun, Ittay Eyal, Giulia Fanti, Bryan Ford, James Grimmelman, Ari Juels, Kari Kostianien, Sarah Meiklejohn, Andrew Miller, Eswar Prasad, Karl Wüst, and Fan Zhang Brookings Institute Working Paper
[J : PETS]	Reputable List Curation from Decentralized Voting (concurrent version) Elizabeth Crites, Mary Maller, Sarah Meiklejohn, and Rebekah Mercer Proceedings on Privacy Enhancing Technologies (The source code for this project can be found here.)

2019

[C : Asiacrypt]	Quisquis: A New Design for Anonymous Cryptocurrencies Prastudy Fauzi, Claudio Orlandi, Sarah Meiklejohn, and Rebekah Mercer Asiacrypt
[C : CCS]	Sonic: Zero-Knowledge SNARKs from Linear-Size Universal and Updatable Structured Reference Strings Mary Maller, Sean Bowe, Markulf Kohlweiss, and Sarah Meiklejohn ACM Conference on Computer and Communications Security (The source code for this project can be found here, and the blog post here.)
[C : AFT]	SoK: Consensus in the Age of Blockchains Shehar Bano, Alberto Sonnino, Mustafa Al-Bassam, Sarah Azouvi, Patrick McCorry, Sarah Meiklejohn, and George Danezis ACM Conference on Advances in Financial Technology
[C : AFT]	PISA: Arbitration Outsourcing for State Channels Patrick McCorry, Surya Bakshi, Iddo Bentov, Sarah Meiklejohn, and Andrew Miller ACM Conference on Advances in Financial Technology (The blog post for this project can be found here.)
[C : USENIX Security]	Tracing Transactions Across Cryptocurrency Ledgers Haaroon Yousaf, George Kappos, and Sarah Meiklejohn USENIX Security Symposium (The blog post for this project can be found here, and it was featured in MIT Technology Review.)
[C : FC]	Why is a Ravencoin Like a TokenDesk? An Exploration of Code Diversity in the Cryptocurrency Landscape (short version) (slides) Pierre Reibel, Haaroon Yousaf, and Sarah Meiklejohn Financial Cryptography and Data Security
[C : NDSS]	Coconut: Threshold Issuance Selective Disclosure Credentials with Applications to Distributed Ledgers Alberto Sonnino, Mustafa Al-Bassam, Shehar Bano, Sarah Meiklejohn, and George Danezis Network and Distributed System Security Symposium (The source code for this project can be found here, and the blog post here.)

2018

[W : CBT]	Contour: A Practical System for Binary Transparency Mustafa Al-Bassam and Sarah Meiklejohn International Workshop on Cryptocurrencies and Blockchain Technology (The source code for this project can be found here.)
[C : Crypto]	Updatable and Universal Common Reference Strings with Applications to zk-SNARKs Jens Groth, Markulf Kohlweiss, Mary Maller, Sarah Meiklejohn, and Ian Miers Crypto
[C : USENIX Security]	An Empirical Analysis of Anonymity in Zcash George Kappos, Haaroon Yousaf, Mary Maller, and Sarah Meiklejohn USENIX Security Symposium (The source code for this project can be found here, and the blog post here.)
[J : S&P]	Top Ten Obstacles along Distributed Ledgers' Path to Adoption (slides) Sarah Meiklejohn IEEE Security & Privacy Magazine, July/August 2018 (The blog post for this project can be found here.)
[J : PETS]	Möbius: Trustless Tumbling for Transaction Privacy Sarah Meiklejohn and Rebekah Mercer Proceedings on Privacy Enhancing Technologies (The source code for this project can be found here.)
[W : BITCOIN]	Egalitarian Society or Benevolent Dictatorship? The State of Cryptocurrency Governance Sarah Azouvi, Mary Maller, and Sarah Meiklejohn The Fifth Workshop on Bitcoin and Blockchain Research
[W : BITCOIN]	Smart Contracts for Bribing Miners Patrick McCorry, Alexander Hicks, and Sarah Meiklejohn The Fifth Workshop on Bitcoin and Blockchain Research (The source code for this project can be found here, and the blog post here.)

2017

[W : CBT]

Who Am I? Secure Identity Registration on Distributed Ledgers

Sarah Azouvi, Mustafa Al-Bassam, and Sarah Meiklejohn
International Workshop on Cryptocurrencies and Blockchain Technology

2016

[C : Asiacrypt]	Déjà Q All Over Again: Tighter and Broader Reductions of q-Type Assumptions Melissa Chase, Mary Maller, and Sarah Meiklejohn Asiacrypt
[C : CCS]	Transparency Overlays and Applications (slides) Melissa Chase and Sarah Meiklejohn ACM Conference on Computer and Communications Security
[J : CACM]	A Fistful of Bitcoins: Characterizing Payments Among Men with No Names Sarah Meiklejohn, Marjori Pomarole, Grant Jordan, Kirill Levchenko, Damon McCoy, Geoffrey M. Voelker, and Stefan Savage Communications of the Association for Computing Machinery
[C : NDSS]	Centrally Banked Cryptocurrencies (slides) George Danezis and Sarah Meiklejohn Network and Distributed System Security Symposium (This work was featured in MIT Technology Review.) (The source code for this project can be found here.)

2015

[C : PKC]	A Profitable Sub-Prime Loan: Obtaining the Advantages of Composite Order in Prime-Order Bilinear Groups Allison Lewko and Sarah Meiklejohn IACR International Conference on Practice and Theory of Public-Key Cryptography
[W : BITCOIN]	Privacy-Enhancing Overlays in Bitcoin (slides) Sarah Meiklejohn and Claudio Orlandi The Second Workshop on Bitcoin Research

2014

[C : CCS]	Algebraic MACs and Keyed-Verification Anonymous Credentials Melissa Chase, Sarah Meiklejohn, and Greg Zaverucha ACM Conference on Computer and Communications Security
[J : TCAD]	Leveraging Gate-Level Properties to Identify Hardware Timing Channels Jason Oberg, Sarah Meiklejohn, Timothy Sherwood, and Ryan Kastner IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems, September 2014
[C : CSF]	Malleable Signatures: New Definitions and Delegatable Anonymous Credentials Melissa Chase, Markulf Kohlweiss, Anna Lysyanskaya, and Sarah Meiklejohn Computer Science Foundations Symposium
[C : Eurocrypt]	Key-Versatile Signatures and Applications: RKA, KDM, and Joint Enc/Sig Mihir Bellare, Sarah Meiklejohn, and Susan Thomson Eurocrypt
[C : Eurocrypt]	Déjà Q: Using Dual Systems to Revisit q-Type Assumptions (slides) Melissa Chase and Sarah Meiklejohn Eurocrypt
[M : Thesis]	Flexible Models for Secure Systems (slides) UCSD Dissertation, April 2014 (This won UCSD's 2015 Chancellor's Dissertation Medal (see here and here). Thanks!)
[C : NDSS]	Botcoin: Monetizing Stolen Cycles Danny Yuxing Huang, Hitesh Dharmdasani, Sarah Meiklejohn, Vacha Dave, Chris Grier, Damon McCoy, Stefan Savage, Nicholas Weaver, Alex C. Snoeren, and Kirill Levchenko Network and Distributed System Security Symposium
[C : CT-RSA]	Rethinking Verifiably Encrypted Signatures: A Gap in Functionality and Potential Solutions (slides) Theresa Calderon, Sarah Meiklejohn, Hovav Shacham, and Brent Waters Cryptographer's Track at the RSA Conference

2013

[J : login]	A Fistful of Bitcoins: Characterizing Payments Among Men with No Names Sarah Meiklejohn, Marjori Pomarole, Grant Jordan, Kirill Levchenko, Damon McCoy, Geoffrey M. Voelker, and Stefan Savage USENIX ;login:, December 2013 (Se puede leer este artículo en español aquí.)
[C : IMC]	A Fistful of Bitcoins: Characterizing Payments Among Men with No Names (slides) Sarah Meiklejohn, Marjori Pomarole, Grant Jordan, Kirill Levchenko, Damon McCoy, Geoffrey M. Voelker, and Stefan Savage Internet Measurement Conference (This work won a Test of Time Award at IMC 2024. It was also featured in Andy Greenberg's fantastic book, Tracers in the Dark. Thanks!) (This work was featured in The New York Times, Wired, The Economist, Forbes, The Washington Post, and more.) Business Week Coindesk (×2) The Economist (×2) Forbes (×2, ×3) Foreign Policy (×2) KPBS (×2) Krebs on Security (×2) MIT Technology Review (×2) The New York Times PC World Slashdot (×2) Vice The Washington Post Wired (×2, ×3, ×4) (One of two IMC papers fast-tracked for Transactions on Networking.)
[C : DATE]	A Practical Testing Framework for Isolating Hardware Timing Channels Jason Oberg, Sarah Meiklejohn, Timothy Sherwood, and Ryan Kastner Design, Automation, and Test in Europe
[C : TCC]	Succinct Malleable NIZKs and an Application to Compact Shuffles (slides) Melissa Chase, Markulf Kohlweiss, Anna Lysyanskaya, and Sarah Meiklejohn Theory of Cryptography Conference
[C : PKC]	Verifiable Elections That Scale for Free (slides) Melissa Chase, Markulf Kohlweiss, Anna Lysyanskaya, and Sarah Meiklejohn International Conference on Practice and Theory of Public-Key Cryptography

2012

[C : Eurocrypt]

Malleable Proof Systems and Applications (slides)

Melissa Chase, Markulf Kohlweiss, Anna Lysyanskaya, and Sarah Meiklejohn
Eurocrypt

2011

[C : USENIX Security]	The Phantom Tollbooth: Privacy-Preserving Electronic Toll Collection in the Presence of Driver Collusion (slides) Sarah Meiklejohn, Keaton Mowery, Stephen Checkoway, and Hovav Shacham USENIX Security Symposium
[W : WOOT]	Heat of the Moment: Characterizing the Efficacy of Thermal Camera-Based Attacks (slides) Keaton Mowery, Sarah Meiklejohn, and Stefan Savage USENIX Workshop on Offensive Technologies

2010

[C : Asiacrypt]	Limitations on Transformations from Composite-Order to Prime-Order Groups: The Case of Round-Optimal Blind Signatures (slides) Sarah Meiklejohn, Hovav Shacham, and David Mandell Freeman Asiacrypt
[C : USENIX Security]	ZKPDL: A Language-Based System for Efficient Zero-Knowledge Proofs and Electronic Cash (slides) Sarah Meiklejohn, C. Chris Erway, Alptekin Küpçü, Theodora Hinkle, and Anna Lysyanskaya USENIX Security Symposium (The source code for this project can be found here, and the project homepage here.)