DatashareNetwork: A Decentralized Privacy-Preserving Search Engine for Investigative Journalists

TL;DR

DatashareNetwork is a decentralized, privacy-preserving search engine designed for investigative journalists to securely find and share sensitive documents across a peer-to-peer network without compromising confidentiality.

Contribution

It introduces a novel decentralized search system combining anonymous authentication, communication, and a new multi-set private set intersection protocol for secure document discovery.

Findings

Proves security of the system

Scales to thousands of users and millions of documents

Demonstrates practical prototype implementation

Abstract

Investigative journalists collect large numbers of digital documents during their investigations. These documents can greatly benefit other journalists' work. However, many of these documents contain sensitive information. Hence, possessing such documents can endanger reporters, their stories, and their sources. Consequently, many documents are used only for single, local, investigations. We present DatashareNetwork, a decentralized and privacy-preserving search system that enables journalists worldwide to find documents via a dedicated network of peers. DatashareNetwork combines well-known anonymous authentication mechanisms and anonymous communication primitives, a novel asynchronous messaging system, and a novel multi-set private set intersection protocol (MS-PSI) into a *decentralized peer-to-peer private document search engine*. We prove that DatashareNetwork is secure; and show using a prototype implementation that it scales to thousands of users and millions of documents.