  Current anonymizing networks have become an important tool for guaranteeing
users' privacy. However, these platforms can be used to perform illegitimate
actions, which sometimes makes service providers see traffic coming from these
networks as a probable threat. In order to solve this problem, we propose to
add support for fairness mechanisms to the Tor network. Specifically, by
introducing a slight modification to the key negotiation process with the entry
and exit nodes, in the shape of group signatures. By means of these signatures,
we set up an access control method to prevent misbehaving users to make use of
the Tor network. Additionally, we establish a predefined method for denouncing
illegitimate actions, which impedes the application of the proposed fairness
mechanisms as a threat eroding users' privacy. As a direct consequence, traffic
coming from Tor would be considered less suspicious by service providers.
