Deanonymization in social media

In today's modern society, communication is to an increasing extent carried out using Internet and social media. This also holds true for communication of unwanted nature, including but not restricted to anonymous threats on Twitter, terrorism propaganda on Telegram, and selling and buying of illegal drugs on Dark Web marketplaces. For this type of communication it is common to use social media user accounts which offer some degree of anonymity, rather than to tell explicitly who the individual behind the communication really is. This report presents various technical solutions for deanonymizing and extracting relevant information about the individuals who own social media user accounts using authorship attribution, alias matching and user profiling techniques. Technical possibilities and limitations with applying the presented techniques on real-world data for crimefighting and counter-terrorism purposes are presented, together with a discussion on ethical and legal problems with using these kind of techniques outside the research laboratory environment.