SkypeMorph: Protocol Obfuscation for Tor Bridges Hooman Mohajeri Moghaddam Baiyu Li  Mohammad Derakhshani. Ian Goldberg Presented by Ganbi

Outline Overview Problem Solution Questions

Anonymity Is it Important? Answer: Tor People’s lives depend on it Authoritative Government vs. Activist Groups Syria, Egypt, China Answer: Tor

Tor Overview

Tor Overview

Tor Overview

Tor Problem The public list of Tor relay nodes can give away all the IP addresses. To fix, developers added “bridge”

Tor Problem

Tor Problem Bridge

4 Ways to get Bridge IP https://Bridges.torproject.org will tell you few based on your IP address and location Mail bridges@torproject.org Via social network You can set up your own and tell your target users directly

Problem Slowly China was able to block most Bridges by probing DPI (deep packet inspection) is still possible

Solution/Paper Pluggable transports SkypeMorph Disguise the Tor packets to look like Skype traffic by using already existing Skype VoIP protocol and user authentication system.

Solution Bridge

Advantages Anyone can use, it’s free! Can transfer reasonable size of data = no bottleneck Encryption already built in In order to stop Tor, they also have to stop legitimate Skype calls, which is highly unlikely Another big advantage: Harder to block bridges even after they are found

Two Methods

Two Methods

Works Cited Moghaddam, Li, Derakhshani, and Goldberg "SkypeMorph: Protocol Obfuscation for Tor Bridges" (n.d.): n. pag. Print. https://www.torproject.org/about/overview.html.en