Ziyang Jin

Computer Science Ph.D. Student at the University of Toronto

About

Portrait of Ziyang Jin

Hi there, welcome to my homepage!

I am a Ph.D. student studying theoretical computer science at the University of Toronto (UofT), where I am very fortunate to be supervised by Akshayaram Srinivasan to work on exciting topics in cryptography.

Previously, I completed my M.Sc. in computer science also at UofT, under great supervision of Mike Molloy in graph theory. Before that, I worked as a software enigneer. A few years ago, I obtained a B.Sc. in computer science at The University of British Columbia (UBC), where I was inspired by Will Evans and Nick Harvey to study theoretical computer science.

Specifically, my current research interests lie in:

  • Secure Multiparty Computation (MPC): Secure multiparty computation (MPC) is about constructing protocols for multiple parties to jointly compute a function while keeping each party's input private. If a subset of parties are corrupted by an adversary, the adversary should not learn anything beyond what can be inferred from corrupted parties' inputs and the function output. Some well-known MPC protocols are [Yao86], [GMW87], [BGW88], [CCD88].
  • Zero-Knowledge Proofs (ZKP): In a zero-knowledge proof system, there is a prover and a verifier. The prover has unbounded computation power while the verifier runs in probabilistic polynomial time. A zero-knowledge proof [GMR85] [Babai85] allows the prover to prove a statement to the verifier such that the verifier only learns that the statement is true, but not how it is proved.

I also like game theory and complexity theory in general. I am also interested in applying cryptography to real-world applications. Feel free to drop me an email for research ideas, or just say hi to me :=)

Contact: [first-name] [at] cs [dot] toronto [dot] edu | LinkedIn | GitHub | CV | ORCID: 0009-0004-6470-3490

Research

Conference Papers

Featured Publication
  1. Non-Interactive Secure Computation with Constant Communication Overhead [Eurocrypt 2026]
    with Yuval Ishai, Naty Peter, Akshayaram Srinivasan
    45th Annual International Conference on the Theory and Applications of Cryptographic Techniques
    Abstract
    We study the communication complexity of non-interactive secure computation (NISC) protocols with security against malicious adversaries. We give a general NISC protocol for any two-party function computed by a Boolean circuit C using only O(|C|λ) bits of communication, where λ is an exact security parameter. This protocol is unconditionally secure in the random oracle model, assuming a standard random OT correlations setup. Compared to Yao's semi-honest protocol, our protocol incurs only a constant communication overhead and achieves security against malicious parties with no additional interaction. Prior works achieved such constant overhead by either using a larger number of rounds or more structured correlations.

Thesis

Frugal Colouring of Graphs with Girth At Least Five
Master's Thesis, University of Toronto
Supervisor: Michael Molloy
Abstract
We proved that for any graph with girth at least five and maximum degree Δ, there exists a (1 + o(1))(Δ / ln Δ)-colouring such that for every vertex v, no colour appears more than polylog(Δ) times in the neighbourhood of v. Our work employs a technique called the semi-random method (a.k.a. the Rödl Nibble) and is based on the proof of [Kim95] for bounding the chromatic number of girth five graphs. We use a non-trivial lopsided Lovász Local Lemma to complete the colouring.

Other Write-ups

  1. Classical Verification of Quantum Computations (from Yael Kalai's talk)
    Fields Notes (Fields Institute Newsletter), 21:7 (Winter 2026), pp. 19-21. The Fields Institute for Research in Mathematical Sciences.

Selected Talks

DateInstitutionEventTitle
2026-03-27University of TorontoTheory SeminarNon-Interactive Secure Computation with Constant Communication Overhead [IJPS26]
2026-01-14University of TorontoCrypto Reading GroupA New Approach to Large Party Beaver-Style MPC with Small Computational Overhead [JLS25]
2025-02-27University of TorontoTheory Student SeminarPolishchuk-Spielman Bivariate Testing and An Application [PS94]
2025-01-17University of TorontoCrypto Reading GroupSNARGs under LWE via propositional proofs [JKLV24]
2025-01-10University of TorontoCrypto Reading GroupUniversal SNARGs for NP from Proofs of Correctness [JKLM24]
2024-06-13University of TorontoTheory Reading GroupPublic-Key Encryption, Local Pseudorandom Generators, and the Low-Degree Method [BKR23]
2024-01-24University of TorontoTheory Student SeminarFrugal Colouring of Graphs with Girth At Least Five
2023-10-11University of TorontoTheory Student SeminarGraph Colouring and the Rödl Nibble
2023-04-26University of TorontoTheory Student SeminarThe Probabilistic Method and Entropy Compression

Teaching

Course Instructor

TermCourseTitleNotes
2023 FallCSC 236Introduction to the Theory of ComputationLEC5101, 111 students
2023 WinterCSC 373Algorithm Design, Analysis, and ComplexityLEC0301, 95 students

Teaching Assistant

University of Toronto
TermCourseTitleNotes
2025 FallCSC 463Computational Complexity and Computability
2026 Winter & 2024 WinterCSC 373Algorithm Design, Analysis, and ComplexityLead TA in 2024 Winter
2025 FallCSC 364Foundations of Computer SecurityLead TA, helped develop assignments and course projects
2026 Winter & 2024 WinterCSC 310Information TheoryTutorial 1 Tutorial 2 Tutorial 4 Tutorial 5 Tutorial 6 Tutorial 12
2024 FallCSC 263Data Structures and Analysis
2023 SummerCSC 240Enriched Introduction to the Theory of ComputationPreparation TA
2025 WinterCSC 165Mathematical Expression and Reasoning for Computer ScienceLead TA
The University of British Columbia
TermCourseTitle
2019 WinterCPSC 320Intermediate Algorithm Design and Analysis
2018 FallCPSC 311Definition of Programming Languages
2018 WinterCPSC 313Computer Hardware and Operating Systems
2016 Summer, 2016 FallCPSC 221Basic Algorithms and Data Structures
2015 Summer, 2015 Fall, 2016 WinterCPSC 121Models of Computation

Supervising Reading Projects on MPC

If you are an undergraduate or master’s student at the University of Toronto and are interested in cryptography—especially secure multi-party computation (MPC)—I would be happy to supervise a reading project. Reading projects are often how theory students begin their research journey, by first learning the fundamental concepts and classical results.

I will provide a sequence of textbook chapters and research papers on MPC. We will meet for one hour each week, during which you will explain the material in your own words. If we happen to identify an interesting problem along the way, we can potentially extend it into a full research project.

If you are interested, feel free to send me an email.

Professional Services

Volunteer

  • I am a volunteer for the Undergraduate Student Research Program (USRP) organized by UofT's Computer Science Student Union (CSSU) on Feb 2, 2026.
  • I am a volunteer for the 2nd Ontario Cryptography Day on Nov 28, 2025.
  • I am a volunteer for the MSc/PhD booth in the 2025 DCS Graduate School Open House on Oct 25, 2025.
  • I am a student ambassador for 2025 Grad Visit Day and a current student panel speaker on Mar 18, 2025.
  • [GAAP 2024] The Toronto Graduate Application Assistance Program is a student-run, volunteer-led program to help students prepare applications to MSc and PhD program in computer science at UofT. I was a mentor in year 2024-2025, mainly for applicants who are interested in theoretical computer science.

Miscellaneous

Unpublished Write-ups

2024Non-Interactive Zero-Knowledge Proof of 3-ColouringNotes
2024Doubly Efficient Proof Systems [GKR08]Notes and Slides
2023Entropy Compression and Frugal ColouringNotes
2022The Puzzle Toad No. 39Our solution

Activities

  • I visited Yifan Song and his students Xiaoyu Ji and Junru Li at Institute for Interdisciplinary Information Sciences (IIIS), Tsinghua University during Feb-Mar 2026.
  • If you are applying for a CS PhD, especially for a theory group, then I recommend Roei Tell's suggestion on how to write the Statement of Purpose
  • [Theory Website Contribution] You are welcome to contribute to the theory group's official website. Having a modern, up-to-date website is crucial for us to attract students and researchers to our group.
  • [Theory Student Seminar] We are looking for speakers. If you are a researcher in theoretical computer science and would like to give a talk, feel free to email tssadmin@cs.toronto.edu
  • [Life in Toronto] My personal recommendations for living in Toronto.

Know-How

© 2026 Ziyang Jin. All rights reserved.