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 research interests are broadly in theoretical and applied cryptography with a special 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

  1. Atomic and Fair Data Exchange via Blockchain
    Ertem Nusret Tas, István András Seres, Yinuo Zhang, Márk Melczer, Mahimna Kelkar, Joseph Bonneau, Valeria Nikolaenko
    2024
    [eprint]

  2. DAO Decentralization: Voting-Bloc Entropy, Bribery, and Dark DAOs
    James Austgen*, Andrés Fábrega*, Sarah Allen, Kushal Babel, Mahimna Kelkar, Ari Juels
    2023
    [arxiv]

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

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

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

  7. 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]

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

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

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

  11. 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]

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

  13. 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]

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

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

  16. 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)]

  17. 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)]

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

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