Prism: Private Verifiable Set Computation over Multi-Owner Outsourced Databases

TL;DR

Prism is a secret sharing-based system enabling efficient, private, and verifiable set operations over multi-owner outsourced databases with minimal communication and scalability.

Contribution

It introduces Prism, a novel secret sharing approach that supports private set operations with verification, scalability, and no server-to-server communication.

Findings

Supports private intersection and union with verification.

Scales efficiently with number of owners and database size.

Operates in at most two communication rounds.

Abstract

This paper proposes Prism, a secret sharing based approach to compute private set operations (i.e., intersection and union), as well as aggregates over outsourced databases belonging to multiple owners. Prism enables data owners to pre-load the data onto non-colluding servers and exploits the additive and multiplicative properties of secret-shares to compute the above-listed operations in (at most) two rounds of communication between the servers (storing the secret-shares) and the querier, resulting in a very efficient implementation. Also, Prism does not require communication among the servers and supports result verification techniques for each operation to detect malicious adversaries. Experimental results show that Prism scales both in terms of the number of data owners and database sizes, to which prior approaches do not scale.