Deanonymizing Tor hidden service users through Bitcoin transactions analysis

With the rapid increase of threats on the Internet, people are continuously seeking privacy and anonymity. Services such as Bitcoin and Tor were introduced to provide anonymity for online transactions and Web browsing. Due to its pseudonymity model, Bitcoin lacks retroactive operational security, which means historical pieces of information could be used to identify a certain user. By exploiting publicly available information, we show how relying on Bitcoin for payments on Tor hidden services could lead to deanonymization of these services’ users. Such linking is possible by finding at least one past transaction in the Blockchain that involves their publicly declared Bitcoin addresses.