1. Tor Bruce Maggs relying on materials from http://www.torproject.org

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3. How Tor Works 3

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5. Tor Cryptography Each router maintains a TLS connection to every other node Each router has a long-term ``identity’’ public/private key pair used to sign TLS certificates Short term ``onion’’ keys are used to set up circuits, negotiate private keys 5

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7. How Tor Works 7

8. Bridge Relays (a.k.a. Bridges) Some ISPs/governments block all traffic to relays that appear in the Tor directory. Bridges are relays that don’t appear in the directory. User has to solve the problem of finding a bridge. 8

9. Solve a Captcha to get Bridge Address 9

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11. Growth of Tor Network 11

12. Growth of Tor Network 12

13. Spike in Number of Users 13

14. Possible Explanation for Spike Botnet “Mevade.A” a.k.a. “Sefnit” a.k.a. “SBC” is using Tor for connectivity http://blog.fox-it.com/2013/09/05/large- botnet-cause-of-recent-tor-network- overload/ 14

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16. Tor Exit Nodes See Plaintext! 16 http://archive.wired.com/politics/security/news/2007/09/embassy_hacks?currentPage=all

17. Tor Browser 17

18. Tor Browser 18

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20. Tor-Aware Web Servers 20 Connect directly to Tor, do not advertise their network addresses.

21. Using Tor as a SOCKS5 Proxy Can tunnel any TCP connection through Tor (and DNS requests) First run the Tor browser, it will also act as a SOCKS5 proxy and accept connections Configure your application, e.g., chat, to use 127.0.0.1 as SOCKS5 proxy 21

22. Configure HexChat to use Proxy 22

23. Now Chatting through Tor 23

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