activity
20202026
most citedPrivate Information Retrieval and Its Applications: An Introduction, Open Problems, Future Directions

2 citations · 3 across the 21 of their papers we have counts for

collaborators

22 papers

cs.IT2026

Feedback Coding Enables Inference-Time Covert Agentic Communication

Sidong Guo, Sajani Vithana, Atefeh Gilani +3

As large language models (LLMs) are increasingly used to automate digital interactions, users can leverage LLM-generated text as cover for covert communication within seemingly ben…

cs.IT2026

Optimal Domain-Aware Privacy Mechanisms for Synthetic Data Generation

Sajani Vithana, Sangwon Jung, Haoyang Hu +3

Differential privacy (DP) imposes fundamental trade-offs between privacy and statistical fidelity in synthetic data generation. While access to public data has been shown to improv…

cs.LG2026

ArcMark: Distortion-Free Multi-Byte LLM Watermark via Optimal Transport

Atefeh Gilani, Sajani Vithana, Carol Xuan Long +3

Watermarking is an important tool for promoting the responsible use of large language models (LLMs). Existing watermarks insert a signal into generated tokens that either flags LLM…

cs.CR2025

HeavyWater and SimplexWater: Distortion-Free LLM Watermarks for Low-Entropy Next-Token Predictions

Dor Tsur, Carol Xuan Long, Claudio Mayrink Verdun +5

Large language model (LLM) watermarks enable authentication of text provenance, curb misuse of machine-generated text, and promote trust in AI systems. Current watermarks operate b…

cs.CV2025

Multi-Group Proportional Representation for Text-to-Image Models

Sangwon Jung, Alex Oesterling, Claudio Mayrink Verdun +3

Text-to-image (T2I) generative models can create vivid, realistic images from textual descriptions. As these models proliferate, they expose new concerns about their ability to rep…

cs.AI2024

Multi-Group Proportional Representation in Retrieval

Alex Oesterling, Claudio Mayrink Verdun, Carol Xuan Long +5

Image search and retrieval tasks can perpetuate harmful stereotypes, erase cultural identities, and amplify social disparities. Current approaches to mitigate these representationa…

cs.IT2024

Correlated Privacy Mechanisms for Differentially Private Distributed Mean Estimation

Sajani Vithana, Viveck R. Cadambe, Flavio P. Calmon +1

Differentially private distributed mean estimation (DP-DME) is a fundamental building block in privacy-preserving federated learning, where a central server estimates the mean of $…

cs.IT2023

Private Membership Aggregation

Mohamed Nomeir, Sajani Vithana, Sennur Ulukus

We consider the problem of private membership aggregation (PMA), in which a user counts the number of times a certain element is stored in a system of independent parties that stor…

cs.IT2023

Quantum Symmetric Private Information Retrieval with Secure Storage and Eavesdroppers

Alptug Aytekin, Mohamed Nomeir, Sajani Vithana +1

We consider both the classical and quantum variations of -secure, -eavesdropped and -colluding symmetric private information retrieval (SPIR). This is the first work to st…

cs.IT2023

Information-Theoretically Private Federated Submodel Learning with Storage Constrained Databases

Sajani Vithana, Sennur Ulukus

In federated submodel learning (FSL), a machine learning model is divided into multiple submodels based on different types of data used for training. Each user involved in the trai…

cs.IT2023

Deceptive Information Retrieval

Sajani Vithana, Sennur Ulukus

We introduce the problem of deceptive information retrieval (DIR), in which a user wishes to download a required file out of multiple independent files stored in a system of databa…

cs.IT2023

Asymmetric -Secure -Private Information Retrieval: More Databases is Not Always Better

Mohamed Nomeir, Sajani Vithana, Sennur Ulukus

We consider a special case of -secure -private information retrieval (XSTPIR), where the security requirement is \emph{asymmetric} due to possible missing communication links…

cs.IT2023★ 2 cited

Private Information Retrieval and Its Applications: An Introduction, Open Problems, Future Directions

Sajani Vithana, Zhusheng Wang, Sennur Ulukus

Private information retrieval (PIR) is a privacy setting that allows a user to download a required message from a set of messages stored in a system of databases without revealing…

cs.IT2023

Private Read-Update-Write with Controllable Information Leakage for Storage-Efficient Federated Learning with Top Sparsification

Sajani Vithana, Sennur Ulukus

In federated learning (FL), a machine learning (ML) model is collectively trained by a large number of users, using their private data in their local devices. With top sparsifi…

cs.IT2023

Private Read Update Write (PRUW) With Heterogeneous Databases

Sajani Vithana, Sennur Ulukus

We investigate the problem of private read update write (PRUW) with heterogeneous storage constrained databases in federated submodel learning (FSL). In FSL a machine learning (ML)…

cs.IT2022

Model Segmentation for Storage Efficient Private Federated Learning with Top Sparsification

Sajani Vithana, Sennur Ulukus

In federated learning (FL) with top sparsification, millions of users collectively train a machine learning (ML) model locally, using their personal data by only communicating…

cs.IT2022

Rate-Privacy-Storage Tradeoff in Federated Learning with Top Sparsification

Sajani Vithana, Sennur Ulukus

We investigate the trade-off between rate, privacy and storage in federated learning (FL) with top sparsification, where the users and the servers in the FL system only share t…

cs.IT2022★ 1 cited

Private Read Update Write (PRUW) in Federated Submodel Learning (FSL): Communication Efficient Schemes With and Without Sparsification

Sajani Vithana, Sennur Ulukus

We investigate the problem of private read update write (PRUW) in relation to private federated submodel learning (FSL), where a machine learning model is divided into multiple sub…

cs.IT2022

Rate Distortion Tradeoff in Private Read Update Write in Federated Submodel Learning

Sajani Vithana, Sennur Ulukus

We investigate the rate distortion tradeoff in private read update write (PRUW) in relation to federated submodel learning (FSL). In FSL a machine learning (ML) model is divided in…

cs.IT2022

Private Federated Submodel Learning with Sparsification

Sajani Vithana, Sennur Ulukus

We investigate the problem of private read update write (PRUW) in federated submodel learning (FSL) with sparsification. In FSL, a machine learning model is divided into multiple s…

cs.IT2022

Private Read Update Write (PRUW) with Storage Constrained Databases

Sajani Vithana, Sennur Ulukus

We investigate the problem of private read update write (PRUW) in relation to federated submodel learning (FSL) with storage constrained databases. In PRUW, a user privately reads…

cs.IT2020

Semantic Private Information Retrieval

Sajani Vithana, Karim Banawan, Sennur Ulukus

We investigate the problem of semantic private information retrieval (semantic PIR). In semantic PIR, a user retrieves a message out of independent messages stored in repli…