how tor works?
TRANSCRIPT
The Onion Router
How Works?
BMS College of Engineering, Bangalore
By :- ONKAR BADIGER
Overview How TOR works?
• Why use TOR?• Places of attack• Anonymity network(TOR design)• Chain of relays• Encryption • Bridges • Extensions
• https everywhere• Tor button• Noscript
Why use TOR?• Compromised ISP• Monitoring ISP• Monitored website• Monitored network• Filtered website(blocked)
ISP Destination(website)
This is how we connect to internet
ISPDestination(website)
Anonymity network
Anonymity network must be between ISP and our destination
ISPDestination(website)
Anonymity network
Places of attack
Compromised ISP(untrusted ISP)Monitored ISP
ISPDestination(website)
Anonymity network
Places of attack
Control parts of anonymity network may attack
ISPDestination(website)
Anonymity network
Places of attack
Website is monitoring to advertise, collect data
etc.
Anonymity network Proxy? VPN?
RELAY
Anonymity network Proxy? VPN?
RELAY
TRUST?
ATTACKER
ATTACKER
RELAY 1
RELAY 2
RELAY 3
ISP
TOR network
Can we trust relays?
RELAY 1
RELAY 2
RELAY 3
ISP
TOR network
What if entry/guard relay is corrupt?
RELAY 1
RELAY 2
RELAY 3
ISP
TOR network
What if exit relay is corrupt?
RELAY 1
RELAY 2
RELAY 3
ISP
TOR network
What if both entry & exit relay are corrupt?
Solution?
RELAY 1
RELAY 5
RELAY 2
RELAY 4
RELAY 3
ISP
TOR network
RELAY 7
RELAY 6 RELAY 8
RELAY 1
RELAY 5
RELAY 2
RELAY 4
RELAY 3
ISP
TOR networkKEY
KEY
KEY
Solution? ENCRYPTION
RELAY 1
RELAY 5
RELAY 2
RELAY 4
RELAY 3
ISP
TOR networkKEY
KEY
KEY
unencrypted
https everywhere
RELAY 1
RELAY 5
RELAY 2
RELAY 4
RELAY 3
ISP
TOR networkKEY
KEY
KEY unencrypte
d
How TOR manages relaying?
Tor button
Tor button
New tor circuit
Tor button is not all about relaying!
Tor button Not just relaying!
Security
Tor button Not just relaying!
Security
Bridges ?
• Entry relays
• Not listed in main TOR directory
Why use Bridges ?• ISP blocks TOR• You don’t want ISP to know that you are using TOR
Types of Bridges ?
Preconfigured bridge
Custom bridge
Tor button Not just relaying!
Network settings
No script
Blocks JavaScriptBlocks javaBlacks flashBlocks other pluginsProtects against clickjacking
How TOR works?
• Why use TOR?• Places of attack• Anonymity network(TOR design)• Chain of relays• Encryption • Bridges • Extensions
• https everywhere• Tor button• Noscript
Check these out…• How to setup tor relay?• How to setup non exit tor relay?• ORBOT (TOR for android)• TAILS (live OS routed through TOR)• Pluggable transports(fakes innocent traffic)• Unblock TOR in college!
The Onion Router
Source : https://www.torproject.org/docs/documentation.html.en
ONKAR BADIGER