On February 4 , Ross Ulbricht was sentenced to a double life sentence for his role in creating and operating the Silk Road darknet marketplace. The Silk Road was groundbreaking in that it combined two privacy-preserving technologies: bitcoin and Tor to enable the seemingly anonymous trade of illicit goods and services. 

The Silk Road attracted close to , buyers and 4, vendors, and facilitated total sales of $ million. The FBI seized approximately , bitcoins from Ulbricht, worth around $ million by that time due to bitcoin’s growing value. These bitcoins were later sold at auction by the US government.

However, total commissions earned by the Silk Road are believed to have totaled around , bitcoins. If that is the case, what happened to the other , bitcoins, now worth some $6 billion? It’s unlikely that it would all have been kept by Ulbricht - he likely had significant expenses in running the marketplace and probably sold some of these bitcoins for US dollars on exchanges. However there has always been the suspicion that proceeds of the Silk Road may remain in circulation.

Fast forward to today and a notable bitcoin transaction has just taken place. 69, bitcoins, worth close to $1 billion, moved out of the bitcoin address 1HQ3Go3ggs8pFnXuHVHRytPCq5fGG8Hbhx, which until this point had the fourth highest balance of any bitcoin address. This address is also notable because an encrypted file has been circulating on hacker forums for the past year, which purportedly contains the cryptographic keys required to seize the bitcoins in this address. If genuine, cracking the password on this file would allow these bitcoins to be moved.

Who owns this address? Well through blockchain analysis we can determine that these funds likely originated from the Silk Road. They left the Silk Road’s wallet back on May 6th when they were worth around $, and then remained dormant for nearly a year, before being moved to the 1HQ address in April

Until today this address has been quiet, apart from bitcoin sent to BTC-e in BTC-e was a cryptocurrency exchange favoured by money launderers, and was taken down by US law enforcement in

The movement of these bitcoins today, now worth around $ million, may represent Ulbricht or a Silk Road vendor moving their funds. However it seems unlikely that Ulbricht would be able to conduct a bitcoin transaction from prison. Alternatively, the encrypted wallet file may have been real, and the password has now been cracked - allowing the bitcoins to be moved.

Either way, the funds are now on the move, and whoever now controls the bitcoins may want to cash them out. Exchanges should be on alert for bitcoin deposits originating from these wallets and use blockchain analytics tools such as Elliptic’s to monitor for this activity and fulfil their compliance obligations.