> There has been research into circumvention systems, particularly for censorship circumvention, that is related this work, but not sufficient for surveillance circumvention. Tor is an anonymity system that uses three relays and layered encryption to allow users to communicate anonymously [19]. VPNGate is a public VPN relay system aimed at circumventing national firewalls [40]. Unfortunately, VPNGate does not allow a client to choose any available VPN, which makes surveillance avoidance harder.

That's damn cursory.