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


Kasra Edalatnejad and Wouter Lueks, EPFL; Julien Pierre Martin; Soline Ledésert, Anne L'Hôte, and Bruno Thomas, ICIJ; Laurent Girod and Carmela Troncoso, EPFL


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. Using a prototype implementation, we show that DatashareNetwork is secure and scales to thousands of users and millions of documents.

Open Access Media

USENIX is committed to Open Access to the research presented at our events. Papers and proceedings are freely available to everyone once the event begins. Any video, audio, and/or slides that are posted after the event are also free and open to everyone. Support USENIX and our commitment to Open Access.

@inproceedings {255354,
author = {Kasra Edalatnejad and Wouter Lueks and Julien Pierre Martin and Soline Led{\'e}sert and Anne L{\textquoteright}H{\^o}te and Bruno Thomas and Laurent Girod and Carmela Troncoso},
title = {{DatashareNetwork}: A Decentralized {Privacy-Preserving} Search Engine for Investigative Journalists},
booktitle = {29th USENIX Security Symposium (USENIX Security 20)},
year = {2020},
isbn = {978-1-939133-17-5},
pages = {1911--1927},
url = {},
publisher = {USENIX Association},
month = aug

Presentation Video