TOR(anonymity network) much like an onion wrapped in layers..

Tor, also known as the Tor Project or the Onion Router, is an online anonymity network designed to conceal its user’s identity and online activities. It does this by first encrypting the user’s communications, and then routing these communications through a network of relays located around the world.Using Tor makes it more difficult for Internet activity to be traced back to the user which includes visits to Web sites, online posts, instant messages, and other communication forms.Tor's use is intended to protect the personal privacy of users, as well as their freedom and ability to conduct confidential communication by keeping their Internet activities from being monitored.
The concept of Onion Routing was first proposed in mid 90s, where it was first funded by the Office of Naval Research and later helped out by DARPA in 1997.The alpha version of Tor, developed by Syverson and computer scientists Roger Dingledine and Nick Mathewson and then called The Onion Routing project, or TOR project, launched on 20 September 2002. Then the first public release occurred a year later on 13 August 2004. Since then, funding for the Tor Project has been provided by a number of different sponsors.

In my previous story i have already talked about how connections are routed through relays.Now we will talk about how repays won't track who are connecting to the network.Tor is designed to put as little trust in relays as possible. It does this through the use of encryption.
let’s take a high-level look at how the encryption works when a client makes a connection through the Tor network.

1. The client encrypts the original data in such a way that only the exit relay can decrypt it.
2. This encrypted data is then encrypted again in such a way that only the middle relay can decrypt it.
3. Finally, this encrypted data is encrypted once more in such a way that only the guard relay can decrypt it.
   This means that we have wrapped our original data in layers of encryption, much like an onion is wrapped in layers.
   

Now lets talk about domain,All the hidden websites use .onion surfix same as .com used in regular website.The .onion domain uses a special naming convention made up of a 16 character alphanumeric string that is generated from a public key. This public key is automatically generated when a new service is configured. For example, a domain name could be “jv6gg3ghd6f7gs8d.onion”. It is primarily due to this unique naming convention that the Hidden Wiki was created in 2008, to help users find their way to ‘important’ and ‘useful’ websites. The Hidden Wiki is split into categories such as Mail Services and Financial Services.
Some of the popular websites of tor are:The hidden wiki, Alpha Bay,Silk Road,torch etc..

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