arXiv subjects

Sujaya Maiyya

Publications and source records attributed to Sujaya Maiyya.

5 recordsLinked to original sources

arXiv2026

Cloak: Heuristic ORAM Optimization Through Fixed Temporal Distribution

Encrypted cloud storage can hide data contents but still leak sensitive information through access patterns. ORAM addresses this by hiding access patterns, but existing ORAM systems are too inefficient to deploy in practice. We present Cloak, an oblivious storage system that dramatically improves performance by leveraging a simple, widely observed property of real workloads: temporal locality, where recently accessed items are more likely to be accessed again soon. Instead of trying to make server accesses look perfectly uniform, Cloak makes server traffic follow a fixed, "recentness-biased" pattern and then uses real queries to fill as much of that traffic as possible. When the workload exhibits temporal locality, Cloak achieves overheads as low as $1.1\times$ over a non-oblivious and unencrypted baseline. Importantly, this heuristic affects only performance, not security. We evaluate Cloak on Netflix click-stream and Ethereum transaction traces, achieving 165,000 and 157,000 operations per second, respectively, on a single machine.

cs.CR↗

arXiv2026

Health+: Empowering Individuals via Unifying Health Data

Managing personal health data is a challenge in today's fragmented and institution-centric healthcare ecosystem. Individuals often lack meaningful control over their medical records, which are scattered across incompatible systems and formats. This vision paper presents Health+, a user-centric, multimodal health data management system that empowers individuals (including those with limited technical expertise) to upload, query, and share their data across modalities (e.g., text, images, reports). Rather than aiming for institutional overhaul, Health+ emphasizes individual agency by providing intuitive interfaces and intelligent recommendations for data access and sharing. At the system level, it tackles the complexity of storing, integrating, and securing heterogeneous health records, ensuring both efficiency and privacy. By unifying multimodal data and prioritizing patients, Health+ lays the foundation for a more connected, interpretable, and user-controlled health information ecosystem.

cs.MM↗

arXiv2020

Fides: Managing Data on Untrusted Infrastructure

Significant amounts of data are currently being stored and managed on third-party servers. It is impractical for many small scale enterprises to own their private datacenters, hence renting third-party servers is a viable solution for such businesses. But the increasing number of malicious attacks, both internal and external, as well as buggy software on third-party servers is causing clients to lose their trust in these external infrastructures. While small enterprises cannot avoid using external infrastructures, they need the right set of protocols to manage their data on untrusted infrastructures. In this paper, we propose TFCommit, a novel atomic commitment protocol that executes transactions on data stored across multiple untrusted servers. To our knowledge, TFCommit is the first atomic commitment protocol to execute transactions in an untrusted environment without using expensive Byzantine replication. Using TFCommit, we propose an auditable data management system, Fides, residing completely on untrustworthy infrastructure. As an auditable system, Fides guarantees the detection of potentially malicious failures occurring on untrusted servers using tamper-resistant logs with the support of cryptographic techniques. The experimental evaluation demonstrates the scalability and the relatively low overhead of our approach that allows executing transactions on untrusted infrastructure.

cs.DB↗

arXiv2019

SeeMoRe: A Fault-Tolerant Protocol for Hybrid Cloud Environments

Large scale data management systems utilize State Machine Replication to provide fault tolerance and to enhance performance. Fault-tolerant protocols are extensively used in the distributed database infrastructure of large enterprises such as Google, Amazon, and Facebook, as well as permissioned blockchain systems like IBM's Hyperledger Fabric. However, and in spite of years of intensive research, existing fault-tolerant protocols do not adequately address all the characteristics of distributed system applications. In particular, hybrid cloud environments consisting of private and public clouds are widely used by enterprises. However, fault-tolerant protocols have not been adapted for such environments. In this paper, we introduce SeeMoRe, a hybrid State Machine Replication protocol to handle both crash and malicious failures in a public/private cloud environment. SeeMoRe considers a private cloud consisting of nonmalicious nodes (either correct or crash) and a public cloud with both Byzantine faulty and correct nodes. SeeMoRe has three different modes which can be used depending on the private cloud load and the communication latency between the public and the private cloud. We also introduce a dynamic mode switching technique to transition from one mode to another. Furthermore, we evaluate SeeMoRe using a series of benchmarks. The experiments reveal that SeeMoRe's performance is close to the state of the art crash fault-tolerant protocols while tolerating malicious failures.

cs.DC↗

arXiv2019

Towards Global Asset Management in Blockchain Systems

Permissionless blockchains (e.g., Bitcoin, Ethereum, etc) have shown a wide success in implementing global scale peer-to-peer cryptocurrency systems. In such blockchains, new currency units are generated through the mining process and are used in addition to transaction fees to incentivize miners to maintain the blockchain. Although it is clear how currency units are generated and transacted on, it is unclear how to use the infrastructure of permissionless blockchains to manage other assets than the blockchain's currency units (e.g., cars, houses, etc). In this paper, we propose a global asset management system by unifying permissioned and permissionless blockchains. A governmental permissioned blockchain authenticates the registration of end-user assets through smart contract deployments on a permissionless blockchain. Afterwards, end-users can transact on their assets through smart contract function calls (e.g., sell a car, rent a room in a house, etc). In return, end-users get paid in currency units of the same blockchain or other blockchains through atomic cross-chain transactions and governmental offices receive taxes on these transactions in cryptocurrency units.

cs.DB↗