The current state of anonymous file-sharing - Marc's Blog
The current state of anonymous file-sharing - Marc's Blog
The current state of anonymous file-sharing - Marc's Blog
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6 Current s<strong>of</strong>tware-implementations<br />
This section will go into detail about the <strong>current</strong> leading implementations <strong>of</strong> the different<br />
anonymity patterns discussed in Chapter 5 and what makes them special (e.g. in terms<br />
<strong>of</strong> scalability). Implementations like OFF (chapter 6.1) will be discussed in more detail<br />
because <strong>of</strong> the importance <strong>of</strong> their implementation in concern to the way the network<br />
works.<br />
6.1 OFF- the owner free <strong>file</strong>system - a brightnet<br />
As the brightnet pattern was a pretty high level approach to the whole subject <strong>of</strong> copy-<br />
right, the focus on the implementation <strong>of</strong> the client will go a bit more into detail.<br />
6.1.1 Structure <strong>of</strong> the network<br />
As discussed in chapter 4.1, there are different generations <strong>of</strong> <strong>file</strong>-<strong>sharing</strong> protocols, OFF<br />
itself is using a <strong>state</strong> <strong>of</strong> the art DHT based approach to structure the whole network<br />
and the data in it. <strong>The</strong> only purpose <strong>of</strong> the DHT structure in OFF is to store and<br />
locate blocks. According to its developers, OFF doesn’t represent the "traditional"<br />
DHT approach when it comes to the initial formed connections when joining the network.<br />
OFF does not maintain a regular node structure and there are no deterministic circles<br />
or chords. This means that there is no "structured" way to create connections inside the<br />
<strong>of</strong>f network, the network becomes connected arbitrarily as nodes search for blocks. This<br />
mechanism bares resemblance to the way Gnutella connects to other nodes (compare<br />
chapter 4.4). This leads to OFF being more highly connected than most other DHT<br />
based networks.<br />
<strong>The</strong> nodes usually have a large number <strong>of</strong> other nodes they "know about”, but they<br />
only are connected to a few <strong>of</strong> them. A node can adaptively add and close connections<br />
as far as it’s necessary for an efficient search in the DHT. <strong>The</strong> management <strong>of</strong> node<br />
connections is actually done in two separate lists, one for the inner-circle <strong>of</strong> nodes which<br />
return blocks consistently and quickly, and one for the outer-circle <strong>of</strong> nodes close to it<br />
(according to the DHT’s distance metric). This allows arbitrary nodes to be located by<br />
asking the closest node you know for the closest nodes it knows.<br />
When looking at the network as a whole, one could say that the network basically<br />
consists <strong>of</strong> three main building blocks: nodes,blocks and URLs.<br />
Nodes Every node on the network has a unique private/public key pair. Every node<br />
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