In particular, we leverage several emerging technologies, such as blockchains, smart contracts, and trusted execution environments to design and prototype a system called SmarTor. Our work aims at distributing the work of these trusted authorities, such increasing resilience against attacks on core infrastructure components of the Tor network. This centralization is concerning since a powerful adversary might compromise these servers and conceal information about honest nodes, leading to the full de-anonymization of all Tor users. In the Tor anonymity network, the distribution of topology information relies on the correct behavior of five out of the nine trusted directory authority servers. This review has been developed from a selection of 57 articles and presents main findings and advances regarding Tor hidden services, limitations found, and future issues to be investigated. In this article, we present a systematic literature review that aims to offer a comprehensive overview of the research made on THS by presenting the state-of-the-art and the different research challenges to be addressed.

However, there is a lack of reviews that sum up the main findings and research challenges. THS is an important research field in Tor.

Among them, we can mention that Tor can hide a user’s IP address when accessing to a service such as the Web, and it also supports Tor hidden services (THS) (now named onion services) as a mechanism to conceal the server’s IP address, used mainly to provide anonymity to websites. This anonymous communication network provides some interesting features. The most famous anonymous communication network is Tor. Anonymous communications networks were created to protect the privacy of communications, preventing censorship and traffic analysis.

Its .onion address on the tor network