Download Tor Network: Understanding Anonymity and Security - Prof. Rachel A. Greenstadt and more Study notes Cryptography and System Security in PDF only on Docsity! SK eee Ce (oes Can
Roger Dingledine
The Tor Project
https://www.torproject.org/
2 Tor: Big Picture ● Freely available (Open Source), unencumbered. ● Comes with a spec and full documentation: Dresden, Aachen, Yale groups implemented their own compatible Java Tor clients; researchers use it to study anonymity. ● 1500 active relays, 200000+ active users, >1Gbit/s. ● Official US 501(c)(3) nonprofit. Seven funded developers, dozens more dedicated volunteers. ● Funding from U.S. Naval Research Lab, Electronic Frontier Foundation, Voice of America, Human Rights Watch, NLnet, Google, ...you? 5 Anonymity isn't just wishful thinking... “You can't prove it was me!” “Promise you won't look!” “Promise you won't remember!” “Promise you won't tell!” “I didn't write my name on it!” “Isn't the Internet already anonymous?” 6 Anonymity serves different interests for different user groups. Anonymity Private citizens“It's privacy!” 7 Anonymity serves different interests for different user groups. Anonymity Private citizens Businesses “It's network security!” “It's privacy!” 10 Regular citizens don't want to be watched and tracked. (the network can track too) Hostile Bob Incompetent Bob Indifferent Bob “Oops, I lost the logs.” “I sell the logs.” “Hey, they aren't my secrets.” Name, address, age, friends, interests (medical, financial, etc), unpopular opinions, illegal opinions.... Blogger Alice 8-year-old Alice Sick Alice Consumer Alice Oppressed Alice .... 11 Businesses need to keep trade secrets. AliceCorp Competitor Competitor Compromised network “Oh, your employees are reading our patents/jobs page/product sheets?” “Hey, it's Alice! Give her the 'Alice' version!” “Wanna buy a list of Alice's suppliers? What about her customers? What about her engineering department's favorite search terms?” 12 Law enforcement needs anonymity to get the job done. Officer Alice Investigated suspect Sting target Anonymous tips “Why is alice.localpolice.gov reading my website?” “Why no, alice.localpolice.gov! I would never sell counterfeits on ebay!” Witness/informer Alice “Is my family safe if I go after these guys?” Organized Crime “Are they really going to ensure my anonymity?” 15 ... so, anonymity loves company! Officer Alice Investigated suspect ... AliceCorp Competitor Citizen Alice Shared anonymity net “???” “???” “???” 16 Yes, bad people need anonymity too. But they are already doing well. Evil Criminal Alice Stolen mobile phones Compromised botnet Open wireless nets ..... 17 Current situation: Bad people on the Internet are doing fine Trojans Viruses Exploits PhishingSpam Botnets Zombies Espionage DDoS Extortion 20 So, add multiple relays so that no single one can betray Alice. BobAlice R1 R2 R3 R4 R5 21 A corrupt first hop can tell that Alice is talking, but not to whom. BobAlice R1 R2 R3 R4 R5 22 A corrupt final hop can tell that somebody is talking to Bob, but not who. BobAlice R1 R2 R3 R4 R5 25 Governments and other firewalls can just block the whole Tor network. Alice Alice S S S S X X 26 R4 R2 R1 R3 Bob Alice Alice Alice Alice Alice Blocked User Blocked User Blocked User Blocked User Blocked User Alice Alice Alice Alice Alice Alice Alice Alice Alice 27 Law enforcement ● We really need to teach law enforcement officers more about Tor -- and about Internet security in general. ● Please introduce me to your favorite law enforcement officers/groups!
