Steve Gibson first covered this back in February of 2011. Amazing how significant this has become.
List to the episode: https://media.grc.com/SN/sn-287-lq.mp3
Show notes: https://www.grc.com/sn/sn-287.htm
It was rebroadcast recently on TWIT.TV as the Story of Bitcoin. Really helps to better understand how it all works.