Mahimna Kelkar

mahimna [at] cs {dot} cornell (dot) edu



I am a PhD student in Computer Science at Cornell University advised by Ari Juels.
My current research interests are broadly in theoretical and applied cryptography with some emphasis on blockchains.

I completed my undergrad at Purdue, where I majored in Computer Science, Mathematics, and Statistics.
At Purdue, I was advised by Aniket Kate and Elias Bareinboim.

I previously helped organize the Security and Privacy Discussion Group (SecDG) at Cornell.

Publications and Preprints

  • Complete Knowledge: Preventing Encumbrance of Cryptographic Secrets
    Mahimna Kelkar*, Kushal Babel*, Philip Daian*, James Austgen, Vitalik Buterin, Ari Juels (*equal contribution)
    2023
    [eprint]

  • Interactive Authentication
    Deepak Maram, Mahimna Kelkar, Ittay Eyal
    2022
    [eprint]
  • GoAT: File Geolocation via Anchor Timestamping
    Deepak Maram, Iddo Bentov, Mahimna Kelkar, Ari Juels
    FC 2024 (to appear)
    [eprint]

  • Truncator: Time-space Tradeoff of Cryptographic Primitives
    (alphabetical ordering) Foteini Baldimtsi, Konstantinos Chalkias, Panagiotis Chatzigiannis, Mahimna Kelkar
    FC 2024 (to appear)
    [eprint]

  • Lanturn: Measuring Economic Security of Smart Contracts Through Adaptive Learning
    Kushal Babel*, Mojan Javaheripi*, Yan Ji, Mahimna Kelkar, Farinaz Koushanfar, Ari Juels
    ACM CCS 2023
    [proc] [eprint]

  • Themis: Fast, Strong Order-Fairness in Byzantine Consensus
    Mahimna Kelkar, Soubhik Deb, Sishan Long, Ari Juels, Sreeram Kannan
    ACM CCS 2023
    [proc] [eprint]

  • Zef: Low-latency, Scalable, Private Payments
    Mathieu Baudet, Alberto Sonnino, Mahimna Kelkar, George Danezis
    WPES 2023
    [proc] [eprint]

  • Buying Time: Latency Racing vs. Bidding for Transaction Ordering
    Akaki Mamageishvili, Mahimna Kelkar, Jan Christoph Schlegel, Edward Felten
    AFT 2023
    [proc] [arxiv]

  • STROBE: Streaming Threshold Random Beacons
    (alphabetical ordering) Donald Beaver, Konstantinos Chalkias, Mahimna Kelkar, Lefteris Kokoris Kogias, Kevin Lewi, Ladi de Naurois, Valeria Nikolaenko, Arnab Roy, Alberto Sonnino
    AFT 2023
    [proc] [eprint]

  • One-Message Secure Reductions: On the Cost of Converting Correlations
    (alphabetical ordering) Yuval Ishai, Mahimna Kelkar, Varun Narayanan, Liav Zafar
    CRYPTO 2023
    [proc] [eprint]

  • Clockwork Finance: Automated Analysis of Economic Security in Smart Contracts
    Kushal Babel*, Philip Daian*, Mahimna Kelkar*, Ari Juels (*equal contribution)
    IEEE S&P (Oakland) 2023
    SCRF Research Impact Award
    [proc] [eprint]

  • Order-Fair Consensus in the Permissionless Setting
    Mahimna Kelkar, Soubhik Deb, Sreeram Kannan
    Short version in APKC 2022
    Best Paper Award
    [proc] [eprint]

  • Secure Poisson Regression
    Mahimna Kelkar, Phi Hung Le, Mariana Raykova, Karn Seth
    USENIX Security 2022
    [proc] [eprint]
    [Usenix Talk (15 min)]

  • MPC-Friendly Symmetric Cryptography from Alternating Moduli: Candidates, Protocols, and Applications
    (alphabetical ordering) Itai Dinur, Steven Goldfeder, Tzipora Halevi, Yuval Ishai, Mahimna Kelkar, Vivek Sharma, Greg Zaverucha
    CRYPTO 2021
    [proc] [eprint]
    [CRYPTO Talk (25 min)]

  • Order-Fairness for Byzantine Consensus
    Mahimna Kelkar, Fan Zhang, Steven Goldfeder, Ari Juels
    CRYPTO 2020
    [proc] [eprint]
    [IC3 Talk (15 min)] [CRYPTO Talk (25 min)] [Chainlink Talk (45 min)]

  • Flexible Signatures: Towards Making Authentication Suitable for Real-Time Environments
    Duc V. Le, Mahimna Kelkar, Aniket Kate
    ESORICS 2019
    [proc] [eprint] [poster]

Other Undergraduate Research

  • Sequence Embeddings using LSTM Networks: Applications to Cyber Security
    Apurva Gandhi*, Mahimna Kelkar*, Joey Ingram, Shawn Martin
    Sandia MLDL 2018
    [poster]

  • Counterfeit Mitigation using Blockchain Technology**
    Aniket Kate, Mahimna Kelkar, Donghang Lu, Easwar Vivek Mangipudi, Pedro Moreno-Sanchez, Krutarth Rao
    CERIAS 2018
    Second Place Best Poster Award
    [poster]

  • Regret Decision Theory
    Undergraduate Honors Project (Supervised by Elias Bareinboim)

* denotes equal contribution
** denotes alphabetical author ordering

Teaching

  • (Spring 2019) - CS 5433: Blockchains, Cryptocurrencies, and Smart Contracts (Cornell)
  • (Fall 2018) - CS 2800: Discrete Structures (Cornell)
  • (Spring 2017 - Fall 2017) - CS 25200: Systems Programming (Purdue)

Internships and Visits

  • (Summer 2023) a16z crypto research - Hosted by Joseph Bonneau, Valeria Nikolaenko, and Tim Roughgarden
  • (Spring 2022) Technion - Hosted by Yuval Ishai
  • (Summer 2021) Facebook Research - Novi Blockchain Cryptography Team
  • (Summer 2020) Google Research - Private Computing Team hosted by Karn Seth and Mariana Raykova
  • (Summer 2018) Sandia National Laboratories: Research Intern
  • (Summer 2017) Amazon: Software Engineering Intern - AWS Lambda
  • (2016 - 2018) FlightProfiler LLC: Chief Technology Officer

Academic Service

  • Program Committee - DeFi Workshop @ FC 2023
  • External Reviewer - CCS 2022, DISC 2022, Eurocrypt 2022, DES Journal (2021), CRYPTO {2020, 2021}, FC 2020, USENIX Security 2020
  • Shadow Program Committee - IEEE S&P 2020