Ricerc@Sapienza

According to Freedom on the Net 2017 report [15] more than 60% of World’s Internet users are not completely free from censorship. Solutions like Tor allow users to gain more freedom, bypassing these restrictions. For this reason they are continuously under deep observation to detect vulnerabilities that would compromise users anonymity. The aim of this work is showing that Tor is vulnerable to app deanonymization attacks on Android devices through network traffic analysis.

Dark Web platforms like the infamous Silk Road market, or other cyber-criminal or terrorism related forums, are only accessible by using anonymity mechanisms like Tor. In this paper we are concerned with geolocating the crowds accessing Dark Web forums. We do not focus on single users. We aim at uncovering the geographical distribution of groups of visitors into time-zones as a whole. Our approach, to the best of our knowledge, is the first of its kind applied to the Dark Web. The idea is to exploit the time of all posts in the Dark Web forums to build profiles of the visiting crowds.

We introduce a new form of encryption that we name matchmaking encryption (ME). Using ME, sender S and receiver R (each with its own attributes) can both specify policies the other party must satisfy in order for the message to be revealed. The main security guarantee is that of privacy-preserving policy matching: During decryption nothing is leaked beyond the fact that a match occurred/did not occur. ME opens up new ways of secretly communicating, and enables several new applications where both participants can specify fine-grained access policies to encrypted data.