How can people remain anonymous online?
Using a distributed, anonymous network, TOR.
What is TOR (Onion Routing)?
Tor is a distributed anonymous communication service using an overlay network that allows people and groups to improve their privacy and security on the internet.
Why would people use TOR?
To keep websites from tracking them, or to connect to those internet services blocked by their local Internet providers.
What is the design of a Tor Networks?
- Overlay network on the user level
- User creates a “circuit” leading to their destination
- All traffic is then routed through the circuit
- Protocol level identification information is removed when passed through each relay
- The destination can not determine the source of the traffic
- Uses TCP with TLS
What does Tor’s hidden services let users do?
Publish web sites and other services without need to revel the location of the site.
How do you establish a circuit?
- Client gets a list of relays from a directory server
- For each connection, the client selects 3 or more relays at random
- An encrypted connection to the first relay is established
- Subsequent connection are established by piping them through the previous relays.
- The final relay performs a TCP handshake with the destination server.
What attacks are circuits vulnerable to?
- Colluding Relays
- Sybil Attacks
- Exit node vulnerability
What is the dark web (Invisible Web)?
All information that cannot be indexed using general web search engines
How do spiders work?
- Start by searching heavily used servers and most popular web pages
- Visits all the links found in the webpages and sends them to the search engine’s indexer (crawling)
- To be discovered, a webpage must be static and linked to.
What are items not found by a search engine’s spider program a part of?
The invisible web
What is the surface web?
Indexed Content. Can be found via traditional search engines like Google
What is the Deep Web?
Indexed and unindexed content. Content which can’t be found using typical search engines. Might require passwords or network permissions.
What is the dark web?
Intentionally hidden content. Can only be accessed with special software like Tor. Might require passwords or permissions.
How is the dark web accessed?
Using Tor, which supports access to .onion pages.
How does onion routing work?
Same as circuit routing.
- When a user sends data it is encrypted in multiple layers.
- Each layer corresponds to a node in the network
- As the data passes through each node, one layer of encryption is peeled off, revealing the next destination
- Process is repeated until destination is reached
What are colluding relays?
It’s when relays co-operate and expose plaintext being sent across a circuit
What is a sybil attack?
Many nodes colluding and user’s create circuits within these nodes.
What is exit node vulnerabillity?
Exit node can read plaintext, which may identify users.
