Lecture 25: Anonymity, Tor

• Slides
• Playlist (length: 42:58)

Anonymity Demo

(True/False) Picking a random student to share a memory with was primarily to prevent someone from being able to trace the memory back to you.

True.

Anonymity

(True/False) Anonymity can be easily obtained by using TLS since it encrypts all of your communication

False. Anonymity is about concealing identity, not necessarily the contents.

Proxies

(True/False) If you use a proxy, noone can trace a webpage request back to you.

False. The proxy itself still knows your identity and your request.

Onion Routing

(True/False) If you use two intermediate non-colluding proxies, no single proxy knows both your identity and the site you visited.

True. One proxy knows your identity, while the other knows the site being visited.

Onion Routing Issues

(True/False) If you are using 5 intermediate proxies, and 4 of those nodes maliciously collude, your anonymity is still guaranteed.

True. Assuming that there is other traffic going on through the honest node, the 4 nodes won’t be able to tell which traffic corresponds to you

Internet Censorship

Evasion

(True/False) Encryption is an effective way to evade censorship

False. Censors can do analysis to recognize and block encrypted messages. Also encryption doesn’t help you if you are accessing a blacklisted IP