TOR: A Cool project from the Internet

TOR - The Onion Router, is an ingenious bit of collaborative work that produced a really interesting anonymity network.

I'd guess a lot of you reading my blog have probably heard of it already,

or you have stumbled across this site because you are looking up information about or doing homework on one of the following TOR's

• TOR: Large Outcrop of bedrock. in Granite country tors are typically round boulders: more info
• TOR: Transit of Rockland: moreinfo
• Written Requirements governing EIA implementation...: More Info
• TOR: Horrible Project management acronym for "total operational requirements" or something. no more info for that thanks.
  
• One of the Two Gods who created the earth and kept the light of truth shining in the Varg's life according to old Norse Mythology, (More Info)
• TOR, common name Mahseer a genera in the family Cyprinidae (carp those darn pesky fish)
• Tor, research station is a Norweigian Antarctic research station in Queen Maud LAnd, in the easternmost part of Princess Martha Coast at Svarthamaren, establish in 1993... (Wikipedia Article)
• Acronym for "Terms Of Reference"

However if you weren't looking for any of the above and you are still here then the TOR I am discussing is the Anonymous network based on "a free software implementation of of second - generation routing"

before I go much further I'll get past a few technical terms so that those who are less technically inclined can keep up.

At A glance, Onion routing is

Onion routing is effectively the the anonymous network version of pass the parcel where you have instructions or a task at each stop...
However I digress,  effectively onion routing is a technique wereby a message or "packet" is repeatly encrypted with layer after layer (think wrapping up the prize in pass the parcel), the message is then sent through multiple network "nodes".

A node is a computer that is attached to a network, sometimes called a host - coming from the original meaning of the word "node" which is the place on a  stem where the leaves are attached.

-Routing = Assigning a path for message or file delivery

These nodes are called "Onion Routers", the analogy comes by way of each router removes one layer of encryption to uncover routing instructions , based on the instructions it then sends the packet to the next router, which agains removes one layer, repeating the process over and over until reaching the final "exit node" which sends the packet on to its intended reciepient.

Whats so great about this way of doing things? in a short description it means that you can send a packet from point A to point B, but to avoid an eavesdropper or someone following the packet (assuming they don't have access to the whole network) it routes the packet via point C, Q, F, J, Z, N and P, before getting to point B.

The whole idea behind the concept of onion routing is to protect the privacy of both the sender and the recipient of a message - while at the same time providing protection for the message content as it is transmitted.

This feat is accomplished, according to the principal of Chaum's mix cascades, via a number of proxies which can then re-route messages in an unpredictable path.


The biggest advantage of onion routing and mix cascades? its not necessary to trust each cooperating router, even if one or more routers are compromised, communication can still be anonymous because each router accepts messages, re-encrypts them, and transmits to another router. only an attacker with the ability to monitor every onion router in a network would have the ability to trace the path of a message through the network.

without that any attacker would have difficulty even if they contral one or more routers on the messages path.


Downsides:

There are several technical, social and otherwise bad downsides to TOR,

technical:
 - DNS leaks: unless you route your dns requests via TOR as well as actual data, you could be compromised via unencrypted dns requests. - this has far reaching consequences, but too detailed to go into here.
- Eaves dropping by exit nodes, any exit node is in the position to capture trafic passing through that doesn't use end to end encryption.

Social:
- Due to the inherent anonymity, TOR has unfortunately been used for illegal purposes, such as child pornography and other illegal uses, this has lead to situations in the past where authorities have seized tor nodes due to this usage.



Applications:
There are a wide variety of applications available that make use of TOR.

Web  browsers with Tor

• OperaTor
• xB Browser - A firefox derivative with integrated tor.

IM / Chat with TOR

• ScatterChat - effectively GAIM with TOR

Theres plenty more both im/browser bundles, and full operating system sandboxes, and various tools. easy to find via google.





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