13 January 2012

Surf Internet Anonymously and break the Country Barriers for Contents

Today I would like to give you an introduction about TOR network. You may think what make me to write this post today. Wel, Indian authorities warned facebook and google that they gonna block and shutdown their sites as China did, if they allow the content to users which government doesn't want their citizens know.. (But they are naming those as abusive contents.) But, my personal opinion is, every person has the right to know the information. And everyone has the sense to decide which are true and which are not.

On other hand, there are already barriers on country based, community based, etc. But we, as computer geeks, need not to worry about those things. We always have an alternative way to get our things done.

TOR network helps users to surf internet anonymously and encrypt all the data flow through the network except the last exit point. Which means no one can make out what page you gonna browse or what data you are sending through, not even your Internet Service Provider.

Before I give you a link to download, I would like to explain how TOR works.


Tor (short for The onion router) is a system intended to enable online anonymity. Tor client software routes Internet traffic through a worldwide volunteer network of servers in order to conceal a user's location or usage from anyone conducting network surveillance or traffic analysis. Using Tor makes it more difficult to trace Internet activity, including "visits to Web sites, online posts, instant messages and other communication forms", back to the user and is intended to protect users' personal freedom, privacy, and ability to conduct confidential business by keeping their internet activities from being monitored.

"Onion routing" refers to the layered nature of the encryption service: The original data are encrypted and re-encrypted multiple times, then sent through successive Tor relays, each one of which decrypts a "layer" of encryption before passing the data on to the next relay and, ultimately, its destination. This reduces the possibility of the original data being unscrambled or understood in transit.

A routing onion (or just onion) is a data structure formed by 'wrapping' a plaintext message with successive layers of encryption, such that each layer can be 'unwrapped' (decrypted) like the layer of an onion by one intermediary in a succession of intermediaries, with the original plaintext message only being viewable by at most:
  1. the sender
  2. the last intermediary
  3. the recipient
If there is end-to-end encryption between the sender and the recipient, then not even the last intermediary can view the original message; this is similar to a game of 'pass the parcel'.
An intermediary is traditionally called a node or router.
To create and transmit an onion, the following steps are taken:
  1. The sender picks nodes from a list provided by a special node called the directory node (traffic between the sender and the directory node may also be encrypted or otherwise anonymised or decentralised); the chosen nodes are ordered to provide a path through which the message may be transmitted; this ordering of the nodes is called a chain or a circuit.
  2. Using asymmetric key cryptography, the sender uses the public key of each chosen node to wrap the plaintext message in the necessary layers of encryption: The public keys are retrieved from an advertised list or by on-the-spot negotiation for temporary use, and the layers are applied in reverse order of the message's path from sender to receiver; with each layer, the client includes information for the corresponding node regarding the next node to which the onion should be transmitted.
  3. As the onion passes to each node in the chain, a layer of encryption is peeled away by the receiving node (using the private key that corresponds to the public key with which the layer was encrypted), and then the newly diminished onion is transmitted to the next node in the chain.
  4. The last node in the chain peels off the last layer and transmits the original message to the intended recipient.
Using this approach means each node in the chain is ideally aware of only 2 other nodes:
  1. the preceding node from which the onion was transmitted.
  2. the proceeding node to which the onion should next be transmitted.
The peeling away of each layer of the onion makes it difficult or impossible to track the onion without compromising a significant number of nodes.

Ok. Enough of information. Now I'll give you the link to TOR client. Download it. Play with it.. Ask us if you have any doubts or questions. You can download it from the official TOR website