The Obfsproxy project exists to achieve the benefits of Tor’s bridges together with traffic obfuscation.

Use cases

Censorship circumvention

Since bridges are easily detected and blocked in some areas (in particular China, but also places where wholesale SSL blocking is used), something like obfsproxy is needed in Tails.

Hiding Tor usage

In situations where both reliability and obfuscation are required despite an adversary having control of the user’s local network traffic obfuscation must also be employed. This traffic obfuscation is imperative where the user’s welfare or liberty my be jeopardised by her use of Tor.

Implementation

The branch feature/obfsproxy currently adds rudimentary support for obfsproxy. It’s possible to just add a bridge like obfs2 $IP:$PORT through Vidalia’s settings and it works (also works with bridge-mode so that even in its current implementation (which doesn’t use DisableNetwork), Tails prevents Tor from talking to the network, and makes Vidalia prompt the user for bridges, obfs2 or not).

Merged in Tails 0.15.

Next steps

• obfsproxy design documentation
• preconfigured obfs2 bridges?