I am a computer science PhD student at Columbia University, where I am a member of the Theory Group and the Crypto Lab. I am fortunate to be co-advised by Tal Malkin and Mihalis Yannakakis. I'm interested in practically motivated theoretical problems in cryptography. Recently I've been especially interested in the intersection of cryptography and machine learning, and have worked on watermarks for AI-generated content.
I earned an Sc.B. in Mathematics-Computer Science from Brown University, where I was very lucky to work with Megumi Ando and Eli Upfal.
Below, authors are listed in alphabetical order unless it's otherwise noted.
You can also find my papers on my dblp and Google Scholar pages.
Interactive Proofs for Verifying Smooth Strategies in Bandits and Games. M. Christ, D. Reichman, J. Shafer. [coming soon!]
Merkle Mountain Ranges are Optimal: On witness update frequency for cryptographic accumulators. J. Bonneau, J. Chen, M. Christ, I. Karantaidou. [ePrint]
Provably Robust Watermarks for Open-Source Language Models. M. Christ, S. Gunn, T. Malkin, M. Raykova. [ePrint, arxiv]
How Much Public Randomness Do Modern Consensus Protocols Need? J. Bonneau, B. Bünz, M. Christ, Y. Efron. [ePrint]
Ideal Pseudorandom Codes. O. Alrabiah, P. Ananth, M. Christ, Y. Dodis, S. Gunn. STOC 2025. [arxiv]
SoK: Watermarking for AI-Generated Content. X. Zhao, S. Gunn, M. Christ, J. Fairoze, A. Fabrega, N. Carlini, S. Garg, S. Hong, M. Nasr, F. Tramer, S. Jha, L. Li, Y. Wang, D. Song. IEEE S&P 2025. [arxiv]
Good things come to those who wait: Dishonest-Majority Coin-Flipping Requires Delay Functions. J. Bonneau, B. Bünz, M. Christ, Y. Efron. EUROCRYPT 2025. [ePrint]
Pseudorandom Error-Correcting Codes. M. Christ, S. Gunn. CRYPTO 2024. [ePrint, arxiv]
Cornucopia: Distributed Randomness Beacons at Scale. M. Christ, K. Choi, J. Bonneau. AFT 2024. [ePrint] (non-alphabetical)
Accountable Secret Leader Election. M. Christ, K. Choi, W. McKelvie, J. Bonneau, T. Malkin. AFT 2024. (non-alphabetical)
SoK: Zero-Knowledge Range Proofs. M. Christ, F. Baldimtsi, K. Chalkias, D. Maram, A. Roy, J. Wang. AFT 2024. [ePrint] (non-alphabetical)
Undetectable Watermarks for Language Models. M. Christ, S. Gunn, O. Zamir. RWC 2024, COLT 2024. [ePrint, arxiv, RWC talk, Slides]
Limits on Revocable Proof Systems, with Applications to Stateless Blockchains. M. Christ, J. Bonneau, Financial Cryptography 2023. [ePrint, a16z crypto talk, a16z crypto blog post] (non-alphabetical)
The Smoothed Complexity of Policy Iteration for Markov Decision Processes. M. Christ, M. Yannakakis, STOC 2023. [arxiv, STOC talk]
Differential Privacy and Swapping: Examining De-Identification's Impact on Minority Representation and Privacy Preservation in the U.S. Census. M. Christ*, S. Radway*, S.M. Bellovin, IEEE S&P 2022. [pdf, IEEE, Columbia Engineering article] (* denotes equal contribution; non-alphabetical)
Poly Onions: Achieving Anonymity in the Presence of Churn. M. Ando, M. Christ, A. Lysyanskaya, T. Malkin, TCC 2022. [ePrint, TCC talk]
Google: Research Intern, supervised by Mariana Raykova and Jonathan Katz. Fall 2024.
CIFRA Institute, Bocconi University: Visiting Student, hosted by Alon Rosen. September 2024.
Google: Student Researcher, supervised by Mariana Raykova. Spring 2024, Summer 2024, and Spring 2025.
Mysten Labs: Intern, cryptography group. Summer 2023.
Simons Institute, Meta-Complexity Program: Visiting Student. Spring 2023.
a16z crypto research: Intern. Summer and Fall 2022.
The Impact of De-Identification on Single-Year-of-Age Counts in the U.S. Census. S. Radway, M. Christ, TPDP 2023. (non-alphabetical)
Differential Privacy and Swapping: Examining De-Identification's Impact on Minority Representation and Privacy Preservation in the U.S. Census. M. Christ*, S. Radway*, S.M. Bellovin, TPDP 2022. (* denotes equal contribution; non-alphabetical)
Counting Kindergarteners: De-identification's Impact on Student Representation. M. Christ, S. Radway, 2020 Census Data Products: Workshop on the Demographic and Housing Characteristics Files 2022 (hosted by the National Academies and Committee on National Statistics).
On the impossibility of stateless blockchains. M. Christ, J. Bonneau. a16z crypto blog 2023.
Zero-Knowledge Range Proofs: Proving Where Your Secret Lies. M. Christ, F. Baldimtsi, K. Chalkias, D. Maram, A. Roy, J. Wang. Mysten Labs blog 2023.
Leader Election from Randomness Beacons and Other Strategies. M. Christ, V. Nikolaenko, J. Bonneau. a16z crypto blog 2022.
Theory of Cryptography Conference '22: Field Notes. M. Christ. a16z crypto blog 2022.
Email: mchrist at cs dot columbia dot edu
If I'm not doing research, I'm probably rock climbing.
