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Mohammad Hajiabadi

Bio: I am an Assistant Professor in the School of Computer Science at the University of Waterloo.

Before that, from 2020-2021, I was an Assistant Professor in the CSE Department at Pennsylvania State University (PSU). Prior to joining PSU, I was a postdoctoral researcher at UC Berkeley, hosted by Sanjam Garg. I spent January 2018-June 2018 visiting Mohammad Mahmoody at the University of Virginia.

I spent September 2016-June 2017 at University College London, hosted by Jens Groth. I completed my PhD at the University of Victoria, under the supervision of Bruce M. Kapron.

I received my BSc degree in Computer Science from Sharif University of Technology, Iran.

Research Interests: Foundations of Cryptography

Thanks to Meta, Mastercard, NSERC and NSF for their support!

News: I co-organized, together with Douglas Stebila, the first occurrence of Ontario Crypto Day, held on June 6, 2024 at the University of Waterloo. The next event is scheduled to take place at the University of Toronto in December 2025.

Students:

Postdoc: Roman Langrehr
PhD: Vahid Reza Asadi (joint with Richard Cleve), Zehou (Tiger) Wu
Master's (current): Karaneh Keypoor, Anas Ibrahim, Pranshu Kumar (joint with Douglas Stebila)
Master's (graduated): Ali Ghadirli, Alice Murphy, Sara Sarfaraz, Daniel Santana (joint with Rafael Oliveira)

Teaching

Computation on Encrypted Data CS 858 (Winter 2025, Winter 2023)
Foundations of Modern Cryptography CS 489/698 (Fall 2025, Fall 2023)
Privacy, Cryptography, Network and Data Security CS 489/698 (Winter 2024)
Introduction to the Theory of Computing CS 360 (Fall 2025, Winter 2023, Fall 2022)
Cryptography / Network Security CS 758 (Fall 2021)
Introduction to Cryptography (Fall 2020, Penn State University)

Program Committees

Eurocrypt 2026, Crypto 2026
Eurocrypt 2025, Asiacrypt 2025, ITC 2025
TCC 2024, Crypto 2024, SAC 2024
Asiacrypt 2023
Crypto 2022, Asiacrypt 2022 , ITC 2022
TCC 2021
TCC 2020, Eurocrypt 2020, ITC 2020.

Publications

Conferences

Sanjam Garg; Mohammad Hajiabadi; Dimitris Kolonelos; Abhiram Kothapalli; Guru Vamsi Policharla
A Framework for Witness Encryption from Linearly Verifiable SNARKs and Applications
Crypto 2025 (Full Version )
Mohammad Hajiabadi; Roman Langrehr; Adam O’Neill; Mingyuan Wang
On the Black-Box Complexity of Private-Key Inner-Product Functional Encryption
TCC 2024 (Full Version)
Jesko Dujmovic; Mohammad Hajiabadi
Lower-Bounds on Public-Key Operations in PIR
Eurocrypt 2024 (Full Version)

Sanjam Garg; Mohammad Hajiabadi; Peihan Miao; Alice Murphy
Laconic Branching Programs from the Diffie-Hellman Assumption
PKC 2024 (Full Version)
Mohammad Hajiabadi; Mohammad Mahmoody; Wei Qi; Sara Sarfaraz
Lower Bounds on Assumptions Behind Registration-Based Encryption
TCC 2023
Mohammad Hajiabadi; Shahram Khazaei; Behzad Vahdani:
Randomness Recoverable Secret Sharing Schemes
ITC 2023 (Full Version). Accepted to Journal of Cryptology 2024.
Sanjam Garg; Mohammad Hajiabadi; Abhishek Jain; Zhengzhong Jin; Omkant Pandey; Sina Shiehian
Credibility in Private Set Membership
PKC 2023 (Full Version)

Alexander Bienstock; Yevgeniy Dodis; Sanjam Garg; Garrison Grogan; Mohammad Hajiabadi; Paul Rösler
On the Worst-Case Inefficiency of CGKA
TCC 2022 (Full version)

Divesh Aggarwal; Nico Döttling; Jesko Dujmovic; Mohammad Hajiabadi; Giulio Malavolta; Maciej Obremski
Algebraic Restriction Codes and their Applications. Accepted to Algorithmica 2023.
ITCS 2022 (Full version).
Melissa Chase; Sanjam Garg; Mohammad Hajiabadi; Jialin Li; Peihan Miao
Amortizing Rate-1 OT and Applications to PIR and PSI
TCC 2021 (Full version).
Navid Alamati; Pedro Branco; Nico Döttling; Sanjam Garg; Mohammad Hajiabadi; Sihang Pu
Laconic Private Set Intersection and Applications
TCC 2021 (Full version).
Sanjam Garg; Mohammad Hajiabadi; Giulio Malavolta; Rafail Ostrovsky
How to Build a Trapdoor Function from an Encryption Scheme
Asiacrypt 2021
Rohit Chatterjee; Sanjam Garg; Mohammad Hajiabadi; Dakshita Khurana; Xiao Liang; Giulio Malavolta; Omkant Pandey; Sina Shiehian
Compact Ring Signatures from Learning with Errors
Crypto 2021 (Full version).
Sanjam Garg; Mohammad Hajiabadi; Rafail Ostrovsky
Efficient Range-Trapdoor Functions and Applications: Rate-1 OT and More
TCC 2020 (Full version).

Nico Döttling; Sanjam Garg; Mohammad Hajiabadi; Daniel Masny; Daniel Wichs
Two-Round Oblivious Transfer from CDH or LPN
Eurocrypt 2020 (Full version).
Sanjam Garg; Romain Gay; Mohammad Hajiabadi
Master-Key KDM-Secure IBE from Pairings
PKC 2020 (Full version). Invited to the Journal of Cryptology.
Nico Döttling; Sanjam Garg; Mohammad Hajiabadi; Kevin Liu; Giulio Malavolta
Rate-1 Trapdoor Functions from the Diffie-Hellman Problem
Asiacrypt 2019 (Full version).
Sanjam Garg; Romain Gay; Mohammad Hajiabadi
New Techniques for Efficient Trapdoor Functions and Applications
Eurocrypt 2019 (Full version).
Sanjam Garg; Mohammad Hajiabadi; Mohammad Mahmoody; Ahmadreza Rahimi; Sruthi Sekar
Registration-Based Encryption from Standard Assumptions
PKC 2019 (Full version).
Mohammad Hajiabadi
Enhancements Are Black-box Non-Trivial: Impossibility of Enhanced Trapdoor Permutations from Standard Trapdoor Permutations
TCC 2018 (Full version).
Sanjam Garg; Mohammad Hajiabadi; Mohammad Mahmoody; Ahmadreza Rahimi
Registration-Based Encryption: Removing Private-Key Generator from IBE
TCC 2018 (Full version).
Sanjam Garg and Mohammad Hajiabadi
Trapdoor Functions from the Computational Diffie-Hellman Assumption
Crypto 2018 (Full version).
Sanjam Garg; Mohammad Hajiabadi; Mohammad Mahmoody; Ameer Mohammed
Limits on the Power of Garbling Techniques for Public-Key Encryption
Crypto 2018 (Full version).
Nico Döttling, Sanjam Garg, Mohammad Hajiabadi and Daniel Masny
New Constructions of Identity-Based and Key-Dependent Message Secure Encryption Schemes
PKC 2018 (Full version).
Jonathan Bootle; Andrea Cerulli, Essam Ghadafi, Jens Groth, Mohammad Hajiabadi, Sune K. Jakobsen
Linear-Time Zero-Knowledge Proofs for Arithmetic Circuit Satisfiability
Asiacrypt 2017 (Full version).
Mohammad Hajiabadi and Bruce M. Kapron
Toward Fine-Grained Blackbox Separations Between Semantic and Circular-Security Notions
Eurocrypt 2017 (Full version).
Mohammad Hajiabadi, Bruce M. Kapron and Venkatesh Srinivasan
On Generic Constructions of Circularly-Secure, Leakage-Resilient Public-Key Encryption Schemes
PKC 2016 (Full version).
Mohammad Hajiabadi and Bruce M. Kapron
Reproducible Circularly-Secure Bit Encryption: Applications and Realizations
Crypto 2015 (Full version). Accepted to Journal of Cryptology 2017.
Mohammad Hajiabadi and Bruce M. Kapron
Gambling, Computational Information and Encryption Security
ICITS 2015 (Full version).
Mohammad Hajiabadi and Bruce M. Kapron
Computational Soundness of Coinductive Symbolic Security under Active Attacks
TCC 2013 (Full version).

Journals

Mohammad Hajiabadi; Shahram Khazaei; Behzad Vahdani:
Randomness Recoverable Secret Sharing Schemes
Journal of Cryptology 2024.
Divesh Aggarwal; Nico Döttling; Jesko Dujmovic; Mohammad Hajiabadi; Giulio Malavolta; Maciej Obremski
Algebraic Restriction Codes and their Applications
Algorithmica 2023.
Mohammad Hajiabadi and Bruce M. Kapron
Reproducible Circularly-Secure Bit Encryption: Applications and Realizations
Journal of Cryptology, 2017.

Recent Invited Talks

Lower-Bounds on Public-Key Operations in PIR. Secure Computation Workshop, Simons Institute, Berkeley, August 2025.
Laconic MPC, PIR and Public-Key Operations. Invited Talk at TPLC: Theory and Practice of Laconic Cryptography Workshop, Eurocrypt 2025, Madrid, May 2025.
Laconic Function Evaluation for Branching Programs. Invited Talk at TPLC: Theory and Practice of Laconic Cryptography Workshop, Eurocrypt 2024, Zurich, May 2024.
Limits on the Power of Garbling Techniques for Public-Key Encryption. Workshop: Lowerbounds in Cryptography, Bertinoro, Italy (July 2019).
New Techniques for Trapdoor Functions and Applications. Bay Area Crypto Day (November 2018).
Trapdoor Functions from the Computational Diffie-Hellman Assumption. IST Austria (October 2018), DC Area Crypto Day (May 2018), Georgetown University (March 2018).
Can public-key encryption be based on one-way functions via non-blackbox garbling techniques? Bay Area Crypto Day (November 2017).
Limitations of Black-Box Constructions in Cryptography. Information Security Group, University College London (February 2017).
New constructions and applications of KDM-secure schemes. Microsoft Research, Redmond (August 2015).
How encryption with standard security copes under stronger forms of attack, with applications to computational soundness, Stanford Security Seminar and UCSD Theory Seminar (December 2013).

Contact Information

Email Address: Email me at XYZmdhajiabadi@uwaterloo.ca, after removing the first three letters.

Cheriton School of Computer Science, University of Waterloo

200 University Avenue West, Waterloo, ON

Canada N2L 3G1

Office: DC 2629

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