I am a computer scientist interested in cryptography and security. BS from Iowa State University ↝ PhD from University of Illinois ↝ Assistant Prof at University of Montana (2009-2013) ↝ Assistant Prof at Oregon State (2013-2019) ↝ Associate Prof at Oregon State (2019-present). I am the only faculty member at Oregon State University whose name contains the substring "OSU".
News
Sep 2023
Congrats to Jaspal Singh and Ian McQuoid, who both successfully defended their PhDs this week! ✓ Jaspal will head to Purdue for a postdoc and Ian will start at MIT Lincoln Labs. Condolences to myself: the sabbatical is finished! ✘
June 2023
Congrats to Gayathri Garimella, who successfully defended her PhD! ✓. She will head to Brown University for a postdoc.
May 2023
VDAF paper accepted to PETS ✓; structure-aware PSI paper accepted to Crypto ✓; and one other other submission rejected from Crypto! ✘
Jan 2023
I think I'll try listing both good ✓ and bad news ✘ here. Both submissions rejected from Eurocrypt 2023!
Oct 2022
Congrats to Lawrence Roy for successfully defending his PhD! Later this month he will join Aarhus University for a postdoc.
Sep 2022
Paper on obfuscating MPC inputs accepted to TCC 2022.
Jun 2022
Paper on structure-aware PSI was accepted to Crypto 2022, and paper on finding a common item in the intersection was accepted to SCN 2022!
May 2022
Paper improving public-key based authentication for SSH was accepted to USENIX Security 2022.
Dec 2021
Paper on symbolic characterization of block cipher modes accepted to CSF 2022!
Aug 2021
Paper on batching base OTs for OT extension accepted to Asiacrypt 2021!
Jul 2021
Paper on malicious PSI for small sets is accepted to CCS 2021.
Jun 2021
Wow!! Our new garbled circuits paper is an honorable mention for best paper at Crypto 2021!
May 2021
Two papers accepted to Crypto 2021:
Oblivious key-value stores for PSI, and beating the half-gates lower bound for garbled circuits.
Feb 2021
Paper on private set operations accepted to PKC 2021.
Sep 2020
Two papers accepted to CCS 2020! PAKE & 1-out-of-N OT and joins on secret-shared data.
May 2020
New paper on private K-means clustering accepted to PETS 2020.
Mar 2020
Congrats to Ni Trieu for defending her PhD and starting a postdoc at UC Berkeley!
Jan 2020
New paper on linear-time malicious PSI accepted to Eurocrypt 2020.
Aug 2019
Several new (and old) papers accepted: secure data exchange to CCSW 2019, private set union to Asiacrypt 2019, and collision resistance in Linicrypt to TCC 2019.
May 2019
I have been promoted to Associate Professor with indefinite tenure!
May 2019
New paper on PSI and sparse OT extension is accepted to Crypto 2019.
Apr 2019
Paper on garbled neural networks now on eprint.
Feb 2019
Paper on speeding up PSI via differentially-private leakage accepted to PETS 2019.
Dec 2018
I will be area chair for cryptography at CCS 2019, so please submit your coolest results! We will have 3 submission deadlines: in Feburary, May, and September.
Dec 2018
Together with David Evans and Vlad Kolesnikov, we wrote a book about MPC. It gives an overview of the current state of the art and main constructions.
Dec 2018
Paper on thumbnail-preserving encryption accepted to NDSS 2019.
Sep 2018
I have started collecting some materials for new grad students and their mentors related to graduate study, so that I can refer to it easily for new students.
Aug 2018
Paper on post-quantum signatures accepted to CCS 2018, and paper on UC hybrid protocols accepted to TCC 2018. Also find me featured in this Oregonion article where I offer some skepticism about bunk cryptanalysis.
May 2018
Paper on authenticated garbling accepted to Crypto 2018. Paper on private contact discovery accepted to PETS 2018.
Apr 2018
I will be delivering a lecture series on 2PC techniques at the crypt@b-it summer school. Come to Germany for a week in July and learn 2PC!
Dec 2017
Slides from Indocrypt tutorial and gate-hiding GC paper now posted.
Nov 2017
Paper on wildcard pattern matching accepted to Financial Cryptography 2018.
Oct 2017
Paper on gate-hiding garbled circuits accepted to Indocrypt 2017. CCS workshop paper on thumbnail-preserving encryption now on eprint.
Sep 2017
This quarter I'm teaching an honors section and traditional section of CS 321, Theory of computation.
Aug 2017
OSU takeover of ACM CCS 2017 has been successful: 3 papers for me (malicious PSI, Duplo, multi-party PSI), 5 for my group members, 6 for Oregon State! Addendum Sep 2017: plus 1 paper at a CCS-affiliated workshop
Jul 2017
I will be on the program committee for Eurocrypt 2018, so get your best results in order for the Sep 19 deadline!
May 2017
Paper on UC hybrid protocols now on eprint.
Mar 2017
I'll be on the program committees for CCS 2017 and Indocrypt 2017. Please submit your best work!
Jan 2017
Hat trick! 3 papers accepted to Eurocrypt 2017! (ZK for RAM programs, malicious PSI, non-interactive 2PC)
Teaching
Typically I teach CS 321 (Theory of Computation) in fall, CS 427 (Intro to Cryptography) in winter, and CS 517 (Computational Complexity) in spring.
Textbook
I am writing an undergraduate textbook on cryptography called The Joy of Cryptography. The book is free and will continue to be free, thanks to support from Oregon State's open textbook initiative.
Mentoring
Current advisees:
- Naman Kumar (PhD, co-advised with Jiayu Xu)
- Jake Januzelli (MS, co-advised with Jiayu Xu)
- David Richardson (MS, co-advised with Jiayu Xu)
- Alice Murphy (PhD)
- Junxin Liu (PhD)
Former advisees:
- Perry Hooker (MS, 2012) → Oracle
- Zhangxiang Hu (MS, 2015) → PhD program U Oregon
- Morgan Shirley (MS, 2017) → PhD program Toronto
- Peter Rindal (PhD, 2018) → Visa Research
- Brent Carmer (PhD, 2018) → Galois
- Naimisha Saireddy (MS, 2019)
- Tommy Hollenberg (MS, 2019)
- Ni Trieu (PhD, 2019 ★) → Berkeley postdoc → Arizona State faculty
- Lawrence Roy (PhD, 2022 ★) → Aarhus postdoc
- Gayathri Garimella (PhD, 2023) → Brown postdoc
- Jaspal Singh (PhD, 2023) → Purdue postdoc
- Ian McQuoid (PhD, 2023) → MIT Lincoln Labs
I have started collecting some materials for new grad students (and their mentors) related to graduate study, so that I can refer to it easily for new students. The materials are biased towards my area of research, but there is also plenty of advice about grad school in general.
2PC Course
In Summer 2018 I was an invited lecturer at the crypt@b-it summer school in Bonn, Germany. I delivered a week-long course on efficient secure computation techniques. The focus was on things that I actually know about: 2PC based on garbled circuits, and PSI.
- Day 1: Overview of secure computation (applications and definitions) and textbook Yao's protocol. slides
- Day 2: Optimizations to garbled circuits (point-permute, free-XOR, half-gates, arithmetic garbling). slides
- Day 3: Optimizations to oblivious transfer (Beaver precomputation, OT extension, IKNP protocol and variants). slides
- Day 4: Protecting Yao's protocol from malicious attacks (cut-and-choose & its subtleties, cheating punishment, dual execution variants, batch cut-and-choose) slides
- Day 5: Private set intersection (classic DH protocol, OT-based equality tests, hashing techniques) slides
- Homework problems for all days
Research
My main research focus is on cryptographic protocols for secure computation. These tools allow parties to perform computations on private data, so that they learn the outcome of the computation but nothing else. I am interested in both theoretical and practical aspects of secure computation techniques.
More specifically, my recent research has focused on:
- Private set intersection: Two parties each hold a set of items, and wish to learn which items they have in common, without revealing anything else about their sets. This special case of secure computation has many real-world applications.
- Garbled circuits: Garbled circuits are one of the few ways to achieve general-purpose secure computation protocols with just a few rounds of communication. I'm interested in making this core technique more efficient.
- Secure computation against malicious adversaries: My group has developed new techniques for hardening secure computation protocols against malicious participants, who may deviate arbitrarily from the protocol.
My research is supported by the NSF, including an NSF CAREER award, and faculty research awards from Google and Visa Research.
Publications
Various bean counting can be found on my Google scholar page and DBLP page. Below I include a link to a free version of almost all articles. Send me email or take advantage of sci-hub if you would like a copy of any paywalled publications.
Malicious Secure, Structure-Aware Private Set Intersection
Crypto 2023 article
Verifiable Distributed Aggregation Functions
PETS 2023 article
How to Obfuscate MPC Inputs
TCC 2022 article
Structure-Aware Private Set Intersection, with Applications to Fuzzy Matching
Finding One Common Item, Privately
SCN 2022 article
A Complete Characterization of Security for Linicrypt Block Cipher Modes
CSF 2022 article
Batching Base Oblivious Transfers
Asiacrypt 2021 article
Three Halves Make a Whole? Beating the Half-Gates Lower Bound for Garbled Circuits
★ best paper honorable mention ★
Crypto 2021 article
Oblivious Key-Value Stores and Amplification for Private Set Intersection
Crypto 2021 article
Private Set Operations from Oblivious Switching
PKC 2021 article
On the (Im)Practicality of Adversarial Perturbation for Image Privacy
PETS 2021 article
Minimal Symmetric PAKE and 1-out-of-N OT
from Programmable-Once Public Functions
CCS 2020 article
Fast Database Joins and PSI for Secret Shared Data
CCS 2020 article
Practical Privacy-Preserving K-means Clustering
PETS 2020 article
Scalable Private Set Union from Symmetric-Key Techniques
Asiacrypt 2019 article
Characterizing Collision and Second-Preimage Resistance in Linicrypt
TCC 2019 article
Secure Data Exchange: A Marketplace in the Cloud
CCSW 2019 article
Cheaper Private Set Intersection via Differentially Private Leakage
PETS 2019 article
Balancing Image Privacy and Usability with Thumbnail-Preserving Encryption
NDSS 2019 article
A Pragmatic Introduction to Secure Multi-Party Computation
Monograph, NOW Publishers (2018) author version
On the Structure of Unconditional UC Hybrid Protocols
TCC 2018 article
TACHYON: Fast Signatures from Compact Knapsack
CCS 2018 article
Optimizing Authenticated Garbling for Faster Secure Two-Party Computation
Crypto 2018 article
PIR-PSI: Scaling Private Contact Discovery
PETS 2018 article
Approximate Thumbnail Preserving Encryption
Workshop on Multimedia Privacy and Security 2017 article
Non-Interactive Secure 2PC in the Offline/Online and Batch Settings
Eurocrypt 2017 article
Sublinear Zero-Knowledge Arguments for RAM Programs
Eurocrypt 2017 article
Reconciling Non-malleability with Homomorphic Encryption
Journal of Cryptology 2017 article
Faster Malicious 2-party Secure Computation with Online/Offline Dual Execution
Fast and Secure Three-party Computation: The Garbled Circuit Approach
CCS 2015 article
Efficient Zero-Knowledge Proofs of Non-Algebraic Statements with Sublinear Amortized Cost
CRYPTO 2015 article
Two Halves Make a Whole: Reducing Data Transfer in Garbled Circuits using Half Gates
Eurocrypt 2015 article
Multi-Party Computation for Polynomials and Branching Programs without Simultaneous Interaction
Eurocrypt 2013 article
Characterizing the Cryptographic Properties of Reactive 2-Party Functionalities
TCC 2013 article
A Unified Characterization of Completeness and Triviality for Secure Function Evaluation
Indocrypt 2012 article
Complexity of Multi-Party Computation Functionalities
Book chapter, IOS Press chapter
Exploring the Limits of Common Coins Using Frontier Analysis of Protocols
TCC 2011 article
Attribute-Based Signatures
CT-RSA 2011 article
A Zero-One Law for Cryptographic Complexity with Respect to Computational UC Security
CRYPTO 2010 article
Cryptographic Complexity Classes and Computational Intractability Assumptions
ICS 2010 article
Complexity of Multiparty Computation Problems: The Case of 2-Party Symmetric Secure Function Evaluation
TCC 2009 article
Cryptographic Complexity of Multi-party Computation Problems: Classifications and Separations
Harvesting Credentials in Trust Negotiation as an Honest-But-Curious Adversary
WPES 2007 article
Unpublished manuscripts & other writings
Fuzzy PSI via Oblivious Protocol Routing
Manuscript 2024 article
Efficient Maliciously Secure Two Party Computation for Mixed Programs
Manuscript 2017 article
Secure Your Data and Compute on It, Too
XRDS: Crossroads, the ACM Magazine for Students, 2015 article
Correspondences regarding cryptography between John Nash and the NSA
The Structure of Secure Multi-Party Computation
University of Illinois PhD dissertation, 2009 pdf
Selected talks
Garbled Circuits for Secure Computation
Indocrypt Tutorial, December 2017 slides
Towards Optimal Garbled Circuit Constructions
Allerton Conference, October 2015 slides
A Brief History of Practical Garbled Circuit Optimizations
Zero-Knowledge Proofs, with Applications to Sudoku and Where's Waldo
Educational talk, University of Montana, December 2008 slides
Other Things
Projects
An Annotated Bibliography of Practical Secure Computation
A reference for researchers in secure computationwebsite
Vamonos
A browser-based platform for algorithm visualizationwebsite
Professional Service
I have served on the following program committees:
- 2026: Crypto (program co-chair)
- 2025: Crypto (area chair), RWC
- 2024: CFail
- 2023: CT-RSA (program chair)
- 2022: PETS (senior PC), CT-RSA, SCN
- 2021: Crypto, RWC, CFail
- 2020: Crypto, Indocrypt, SCN, CFail
- 2019: ACM CCS (area chair), IEEE S&P, Indocrypt, CCSW
- 2018: Crypto, Eurocrypt, TCC
- 2017: ACM CCS, Indocrypt
- 2016: Crypto, PETS
- 2015: PETS, ACNS
- 2014: Eurocrypt, TCC
- 2012: TCC
- 2011: PKC
I have been an associate editor for ACM Transactions on Privacy and Security (TOPS) since Dec 2020.
I am on the organizing committee for TPMPC: Theory and Practice of Multi-Party Computation Workshops and for CFAIL: Conference for Failed Approaches and Insightful Losses in Cryptology.
From 2014 to 2019 I served as communications secretary for the International Association for Cryptologic Research.
Miscellany
I have a personal website (never updated), a Flickr page, a Github page, and a few Youtube videos.