Security 7 - Tracking

Computer security is a big and kind of dramatic area which lends itself to movie plots and fear. There are real threats our there, but staying safe is not that hard.

IP Addresses - Tracking

• Previously: every computer on the internet uses an IP address
  e.g. 171.64.64.110
• Each packet has from: and to: IP addresses
• That's how they get back and forth!
• IP address is assigned by the internet-provider
• IP address generally can be traced to a city or perhaps building
  (The service provider has the most info, not necessarily public)
• Geo ip http://www.geoipview.com/

Scenario 1 - Server Log IP

• Web browser contacts web server
• Both have IP addresses!
• A server logs the browser IP of every request it gets in "log files"
• e.g. criminals are using some server to communicate
  -The FBI gets the logs, tries to figure out who each IP is
  -IP address is not a person
  -FBI will need additional info to say who is behind an IP

Scenario 2 - VPN

• VPN - Virtual Private Network
• A tunnel for packets
• Hides the true source of a packet
• The packet appears to be from the VPN endpoint
• e.g. I am in Hawaii but want Stanford to think I'm in Palo Alto
  1. Establish VPN tunnel with end-1 in Hawaii and end-2 in Palo Alto
  2. From Hawaii packet goes through VPN tunnel and on to the server
  3. As seen by the server, the packet is from: end-2, hiding my location
• A VPN can also feature encryption
• However HTTPS does that more easily
• Many people in China use VPNs to get content from the internet at large
• Famous ironic example: creator of China firewall has web access blocked in talk
  has to use VPN
  Blocking the internet to shape people's thoughts is dumb!
  http://time.com/4283248/china-great-firewall-fang-binxing-censorship/

Scenario 3 - China

• China's government seeks to control what info is on the internet
• At the router level, government controls routers between china and the world
• A the simple step, block packets going to wikipedia, youtube, nytimes
• More intrusive: look inside packets, track down prohibited speech
  -https can protect the packets
  -but not if China requires citizens to use government controlled service
  -Orwellian!