Research Output

Publications

Source code for these papers is not public. For access, email me.

2026

CRSP-FL: Efficiently Scaling Private Frequency Estimation to Resolve Data Heterogeneity in Federated Learning

Harish Karthikeyan

Under Submission Preprint Cryptography Security
Code: contact

SHARP-FL: Single-Round Global Frequency Reweighting for Private Federated Learning

Harish Karthikeyan

Under Submission Preprint Cryptography Security
Code: contact

SESAME: Communication-Optimal Secure Aggregation for Sign-Based Federated Learning

Harish Karthikeyan

Under Submission Preprint Cryptography Security
Code: contact

Maliciously Secure Federated U-Statistics with Non-Interactive Verifiable Noise

Harish Karthikeyan

Under Submission Preprint Cryptography Security
Code: contact

TAPAS: Efficient Two-Server Asymmetric Private Aggregation Beyond Prio(+)

Harish Karthikeyan and Antigoni Polychroniadou

Contributed talk: TPMPC 2026

Under Submission Preprint Cryptography
PDF Code: contact

HashMark: Watermarking Tabular (Synthetic) Data For Machine Learning Via Cryptographic Hash Functions

Harish Karthikeyan, Leo de Castro, Antigoni Polychroniadou, Manuela Veloso, Tucker Balch

Regulatable ML @NeurIPS2025, NeurIPS 2025 Workshop on GenAI in Finance

Under Submission ML Preprint NeurIPS ’25 Workshop
PDF Code: contact

AgentCrypt: Advancing Privacy and Secure Computation in AI Agent Collaboration

Harish Karthikeyan, Yue Guo, Leo de Castro, Antigoni Polychroniadou, Leo Ardon, Udari Madhushani Sehwag, Sumitra Ganesh, Manuela Veloso

Regulatable ML @NeurIPS2025,NeurIPS 2025 Workshop on Scaling Environments for Agents

Under Submission Cryptography ML / Agents Preprint NeurIPS ’25 Workshop
ePrint arXiv Code: contact

Updatable Public-Key Encryption from Class Groups: New Constructions with Better Efficiency

Harish Karthikeyan and Antigoni Polychroniadou

Financial Cryptography 2026 Cryptography
PDF
2025

Armadillo: Robust Secure Aggregation for Federated Learning with Input Validation

Yiping Ma, Yue Guo, Harish Karthikeyan, Antigoni Polychroniadou

Early version: NeurIPS 2024 AIM-FM Workshop

ACM CCS 2025 Federated Learning Security Cryptography
arXiv ACM DL Code: contact

OPA: One-shot Private Aggregation with Single Client Interaction and its Applications to Federated Learning

Harish Karthikeyan and Antigoni Polychroniadou

Early versions: TPMPC ’25 · NeurIPS ’24 Workshop · AAAI ’25 Workshop

CRYPTO 2025 Cryptography Federated Learning
ePrint Code: contact
2024

PriDeCT: Towards Public Consensus, Private Transactions, and Forward Secrecy in Decentralized Payments

Yue Guo, Harish Karthikeyan, Antigoni Polychroniadou, Chaddy Huussin

IEEE S&P 2024 Cryptography Security
ePrint IEEE Code: contact

Method and System for Private Decentralized Forward-Secure Confidential Transactions

Yue Guo, Antigoni Polychroniadou, Harish Karthikeyan

Published as US20240177150A1 (May 2024) · Granted Feb 2026

US Patent 12,555,107 Cryptography
Patent
2023

Forward Security Under Leakage Resilience, Revisited

Suvradip Chakraborty, Harish Karthikeyan, Adam O'Neill, C. Pandu Rangan

CANS 2023 Cryptography Theory
ePrint Springer
2022

Forward-Secure Encryption with Fast Forwarding

Yevgeniy Dodis, Daniel Jost, and Harish Karthikeyan

TCC 2022 Cryptography Theory
ePrint

On Seedless PRNGs and Premature Next

Sandro Coretti, Yevgeniy Dodis, Harish Karthikeyan, Noah Stephens-Davidowitz, Stefano Tessaro

ITC 2022 Theory
ePrint LIPIcs

Encapsulated Search Index: Public-Key, Sub-linear, Distributed, and Delegatable

Erik Aronesty, David Cash, Yevgeniy Dodis, Daniel H. Gallancy, Christopher Higley, Harish Karthikeyan, Oren Tysor

PKC 2022 Cryptography
PDF

Small-Box Cryptography

Yevgeniy Dodis, Harish Karthikeyan, and Daniel Wichs

ITCS 2022 Cryptography Theory
PDF
2021

Updatable Public Key Encryption in the Standard Model

Yevgeniy Dodis, Harish Karthikeyan, and Daniel Wichs

TCC 2021 Cryptography
PDF
2019

Seedless Fruit is the Sweetest: Random Number Generation, Revisited

Sandro Coretti, Yevgeniy Dodis, Harish Karthikeyan, Stefano Tessaro

CRYPTO 2019 Theory Cryptography
PDF
2015

An Efficient Multiple PKG Compatible Identity Based Authenticated Key Agreement Protocol

Harish Karthikeyan, Suvradip Chakraborty, Kunwar Singh, C. Pandu Rangan

Inscrypt 2015 Cryptography
ePrint