Evaluating retrieval and ranking strategies on the dark web: a focus on Tor search engines

Purpose In the dark web, information retrieval faces the challenge of locating what is to be hidden. The criteria for identifying and organizing the results are uncertain, as search engines must overcome some difficulties related to the particularities of content and anonymity preservation different from the surface web. The purpose of this study is to examine the extent to which search engines operating on the dark web implement web positioning strategies, with the aim of assessing their alignment with conventional SEO practices. Design/methodology/approach This paper analyzes the underlying factors in the Tor network search engines, focusing on information retrieval and ranking algorithms. For the evaluation, retrieval rates for different queries in three search engines were examined. Regarding positioning, SEO strategies of readability, accessibility, usability, credibility and use of metadata were considered. Findings The results reveal that Dark Web search engines apply search strategies and web positioning, although ineffectively, as a small number of documents of dubious relevance are retrieved. This study has identified positioning factors aimed at improving retrieval and user experience, detecting the need for an alternative approach to search for more relevant, up-to-date and secure results. Research limitations/implications The main limitations of the study are the characteristics of Tor addresses, which have high volatility in an environment that requires technological expertise to ensure security. Due to the need for a sufficiently large set of documents for analysis, no restrictions were applied to the type of questions and documents. Practical implications The main technical advantages presented by the study provide a foundation for establishing mechanisms to securely exchange noncriminal information on this network. Trust mechanisms from the visible web are not valid in this environment, so proposed solutions are needed to ensure sufficient trust in this context. An interesting aspect is understanding how information exchange occurs in an environment characterized by inherent distrust. Social implications The darknet emerged as a secure platform for the exchange of information among individuals threatened under dictatorial regimes, where freedom of expression is curtailed. Some countries that restrict the exchange of information by political dissidents have limited the dissidents' ability to report abuses. The malicious use by cybercriminals puts this network at risk, making it essential to understand the retrieval mechanisms and establish methods that facilitate reporting by persecuted groups and individuals. Originality/value The adaptation and exploration of SEO factors in such a distinct environment are part of what gives this study its novelty. This paper bridges the gap between theory and practice by discussing how findings could be used to improve search engine design, accessibility and credibility on the dark web.