Anh's blog: How far anonymity can be abused ?

Well, as far as P2P file sharing is concern, anonymity is probably the most desirable feature. With all the current news headlines of individual sharers getting busted, more users become aware of this anonymity thing.

While providing anonymity for P2P is still an active research field, several infrastructures that offer users' anonymity already existed. TOR is perhaps the most well-known system. It was designed as a low-latency anonymous communication channel. In other words, ones can use TOR to gain pretty strong anonymity while doing interactive communications such as Web browsing, chat, online game, etc.. (which require low-latency/fast communication).

One side-effect of TOR, as well as many other anonymous system, is the so-called reply-block. Long story short, it allows service providers (Web, streaming..) to offer their services anonymously. You may ask how it could be possible, because all the online services that have been used today was identified by an IP address (for message routing). This concept stemed from David Chumn's design back in the 80s, where a reply-block was acting like an anonymous email address, and that identity of the owner was extremely difficult to reveal. In context of TOR, a service can be identified by its reply-block, and TOR infrastructure will be routing any message destined to this address correctly. You can imagine that TOR infrasturcture is something similar to the current Internet infrastructure, but hosts are not labelled by a IP address, and identity of the address can not be revealed (in constrast, one can take a subpoena to an ISP and demands account information of the owner).

The good thing about TOR is that it is open source and freely available for Linux community (it may have a Windows version as well). I was quite intrigued to give it a try and to my suprise:
1. It seems to works correctly. Even though i did not look at it at the deepest level of communication, i can check that my IP address that was seen by some online services (that i was connecting to) was different from my real one. For example, typing google.com would send me to the google.de site, which meant that the last point of my anonymous tunnel was located in Germany.

2. Slow. It took about 7 seconds more in average to connects to wikipedia. That is not low-latency to me. However, with everything going on uder the surface, especially with public key encryption/decryption being very costly, it was good already.

3. I found out a whold new world, the hidden world that have been existing for a while on the Internet. They are named hidden services. By using reply-block mechanism, many people can publish their stuff on the Internet anonymously. I was excited to explore how people would use such censorship-resistant, anonymous communication for. Censoring documents involves preventing them from being published. For example, Chinese goverment was believed to have forced Google to censor some pictures/documents. However, this thing is far from international, you stop people publishing in one place, they can hire a server at a different country and make it public. Different jurisdication in different countries prevent censorship from being effective.
Anonymity, however is at a different level (much higher). Some stuff on the Internet should be internationally considered as illegal, such as drugs, weapons, child pornography ... With strong anonymity, these thing can happen.

Because those hidden services require proper configuration to access, i will shows some screenshot here, just for you to get some idea (to see them more clearly, you would have to click to the pictures):

This one is somebody's expression on the abuse of languages, services on hidden Websites, forums and other services.