I'm interested in how this chapter will fit in - what is the real thesis topic?


In any case for the chapter you should consider doing a review of bitcoin mining profitability in the past since it greatly influenced the current state of the bitcoin economy - especially since it widely distributed coins to those that were willing to turn their cpu and then later gpu cycles to it.  You could discuss the current state where it requires dedicated ASIC (application-specific integrated circuits) to have profitability and the hardware that is profitable generally requires a pre-order gamble to acquire in a timely manner.  Then I suggest you turn an eye towards the future.  The total computational power of the network has grown exponentially - fueled in my opinion somewhat by increased bitcoin value and somewhat by technology that is more efficient - can this continue for the long term?  While moore's law has stunned some by holding true with exponential growth in computing power over more than 40 years - the limited pool of resources for bitcoin (the remaining coins to be minted + transaction fees) will likely mean mining power growth will likely become linear and logarithmic after a time.  But you certainly shouldn't try to predict that timeframe too accurately - the error bars are probably measured in tens of months.  Not to mention the exit of the home miner - soon typical household electric circuits will be sufficient to host the required juice to keep relevant miners powered.

You could look at the cost of such a large bitcoin computation network.  Both the social cost in current electric consumption which has some environmental implications and in terms of how much investment at current prices would be required to increase difficulty.  If everyone adding computation to the network is paying the pre-order retail price of $3 per GH/s how much capital was spent acquiring minng hardware last month?  Is that sustainable?

Lots of great avenues for topics, I hope you've carved out a good one.  I also encourage you to use analogies to relate the at times tediously technical details of bitcoin operation.  Things like What is difficulty?  What is one bitcoin?  Why is it secure?  Analogy is a technique often leaned upon by the great physicists to translate the technical into the everyday - think http://en.wikipedia.org/wiki/Schr%C3%B6dinger%27s_cat