International Association
for Cryptologic Research

The Bitcoin scheme is one of the most popular and talked about alternative payment schemes. It was conceived in 2008 by the mysterious Satoshi Nakamoto, whose real identity remains unknown even

though his bitcoin holdings are believed to be worth several hundred

million dollars. One of the most active parts of the Bitcoin ecosystem was the Silk Road marketplace, in which highly illegal substances and services were traded. It was run by another mysterious person who called himself Dread Pirate Roberts (DPR), whose bitcoin holdings are also estimated to be worth hundreds of millions of dollars at today\'s exchange rate. On October 1-st 2013, the FBI arrested a 29 year old person named Ross William Ulbricht, claiming that he is DPR, and seizing a small fraction of his bitcoin wealth. In this paper we use the publicly available record to trace the evolution of his holdings in order to find how he acquired and how he tried to hide them from the authorities. For example, we show that all his income from the months of May, June and September 2013, along with numerous other amounts, were not seized by the FBI. One of the most surprising discoveries we made during our analysis was the existence of a recent substantial transfer (which was worth more than 60,000 dollars when made on March 20-th 2013, and close to a million dollars at today\'s exchange rate) which may link these two mysterious figures.