Encryption puts a digital padlock on information so it can’t be viewed. But eventually the person with the keys has to unlock the information in order to see it. That’s why law enforcement agents had to catch Ulbricht while he was logged into the SIlk Road’s admin console.
Ulbricht occasionally took his laptop out in public to work. So agents staked out his San Francisco neighborhood until he showed up at the local library, set up his laptop and logged on. They arrested him before he could close the laptop lid, which would have logged him out and locked the contents. Ulbricht didn’t do himself any favors by working that day with his back turned to the rest of the room — something he had warned other Silk Road administrators not to do.
Because law enforcement agents snatched the laptop before Ulbricht had closed it, the contents of its hard drive were completely accessible to them, including the chat logs, a personal journal, Silk Road spreadsheets, and most importantly, Dread Pirate Roberts’ private encryption keys.
In the end, encryption did as much to betray Dread Pirate Roberts’ identity as to protect it.
Ulbricht had affixed Dread Pirate Roberts’ public encryption key to an untold number of Silk Road-related emails and forum posts. A public key allows someone to verify that a message comes from the person who claims to have sent it. On Ulbricht’s computer, in a folder marked “keys,” were the private keys used to sign Dread Pirate Roberts’ messages. Law enforcement had only to verify that the messages, many of them incriminating, came from Dread Pirate Roberts, by using the public key found on the laptop.