Some notes
Mix-based systems🟨
Created in 1981 by David Chaum. Very similar to the previous one, in practice, in the end, it acts as a proxy but not only does it take and receive, but it also mixes together the packets it has received from the sources, applying its key.
Disadvantage: The public-private mixing system is very slow. For this reason, a network of nodes is established, each having a symmetric key, making it much faster.
The important thing to note is that this system has been influential in modern tor networks.
Fullz dataleak
A fullz dataleak has the minimum indispensable to create bank accounts or pay with credit cards
- Name and Surname
- birthdate
- fiscal code
- phone number
- residence address
So its very important to keep this information private!
The Tor Ecosystem
This system tries to anonymize the user with principles similar to #Anonymity by proxy. The initial user message goes through different relays before reaching the end destination. The system is a little bit more complex than this, so we are breaking down a connection example
It’s called onion because each relay has only an outer layer of the onion. The core is what the end user receives.
How Tor Works
The Tor network sends the payload through three random relay servers in the network. Information about what we are accessing, from who, is not accessible. But some information is still accessible, for example:
- Our ISP knows that we are trying to access the Tor network, because we need a listing of tor nodes.
- The exit relay knows to whom we are talking to, as this information is needed to send the message.
As the exit node is often public, they are often blocked by institutions, like banks.
#### Overlay networks
> Rete “overlay”. Una rete **chiusa** al quale interno vengono distribuiti dati in **forma anonima**. Questo è il principio dei servizi onion.
Service setup
When a service is put onto this network it connects to some intro nodes whose role is to introduce clients to the servers. The map server->intro nodes is then saved into another node, which is called the directory node. This node contain mappings from services and intro points.
Client Connection
The client that wants to connect to an anonymous service needs to know who are the intro nodes.
He asks the directory node who gives him the connections. Directory gives him a descriptor, that is verified with the original .onion address who acts as a secure key.
The the client asks a secret string from a rendezvous node. The secret string and rendezvous are then sent to the intro nodes, and these sent it to the original service that decides whether to accept or not that service.
If it accepts, it sends the secret to the rendezvous, who then creates a circuit between the client and the server. Now everything can be sent and received anonymously.