Hi all,
Our proposed defenses (Counter-RAPTOR) against active routing attacks on Tor will soon appear at IEEE S&P in May. It's also available here: https://arxiv.org/abs/1704.00843
In short, we have two lines of defenses: (1) Entry Guard Selection (proactive defense, https://github.com/inspire-group/Counter-Raptor-Tor-Client) (2) BGP Monitoring on Tor relays (reactive defense, in progress of making it public)
Please let us know if you have any questions/comments.
Thanks! Yixin