Circuit shaping

- [Instruction] Circuit reconstruction attacks … depend upon an adversary compromising large portions … of the Tor network … and then hoping that their target selects a circuit … that uses only to those compromised nodes. … But what if an attacker could control the nodes … that a victim selects … and instead of using random nodes, … the victim chooses to use only compromised nodes? … This is an attack known as circuit shaping. … The attacker compromises the victim's computer in some way … and then tampers with their Tor software … causing them to select circuits … built exclusively from nodes that are under … the attacker's control. … Now circuit shaping isn't easy. … It requires either hacking into the victim's computer … and altering the Tor software that's already there. … Or tricking the end user into installing … a compromised version of Tor, … but if it's successful … this attack will completely undermine the security … of all Tor communications from that system. … As an end user, the best protection against circuit shaping …