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.

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@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,

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