Dread Pirate Roberts (DPR) is the alias used by Ross Ulbricht, the creator of darknet market Silk Road. The pseudonym is a reference to the fictional character of the same name from the novel The Princess Bride, which was later turned into a film.

The Silk Road, best known for selling illegal drugs, operated as a Tor hidden service that would enable the users to browse it anonymously and securely from 2011 to 2013. Transactions on the site were carried out with bitcoin for privacy. Before it was shut down in 2013, the Silk Road handled over $1.2 billion worth of illegal goods and services, with over $79.2 million in commissions, according to the criminal complaint against Ulbricht. Following the closure of the site, the FBI seized 144,000 BTC (worth around $28.5 million at the time) which it said belonged to Ulbricht. The U.S. Marshals Service later sold off the bitcoin in four separate auctions. 

The Dread Pirate Roberts (often abbreviated DPR) alias was created not by Ulbricht but by a still-unidentified Silk Road marijuana seed dealer who utilized the names Variety Jones and Cimon, and whom Ulbricht called a “mentor.” In 2016, Ulbricht’s lawyers said they had found evidence that someone had logged into the Dread Pirate Roberts account six weeks after Ulbricht’s arrest, when he was in federal custody. They posited that more than one person could have been using the account.

Internal Revenue Service (IRS) agent Gary Alford first linked Ulricht to the alias in June of 2013 through a post on the internet forum Bitcointalk from a user called "altoid," who sought a bitcoin “IT pro” to be the lead developer for a “venture backed bitcoin startup company.” The post listed an email address with Ulbricht’s full name in it, and the name “altoid” was later used elsewhere to promote the Silk Road shortly after its launch. Ulbricht was arrested later that year.

In 2015, Ulbricht/DPR was convicted of four narcotics charges and three charges related to money laundering, computer hacking and trafficking fraudulent identity documents. Furthermore, the original criminal complaints alleged he paid to have two people murdered. The complaint accuses Ulbricht of hiring a Silk Road user to kill another user who threatened to expose the identities of thousands of the site’s customers. It also alleges he sought to have another person murdered whom he feared would give his information to the FBI.

Ulbricht was sentenced to life in prison without the possibility of parole later in 2015, and is serving his sentence at the United States Penitentiary in Tucson, Arizona.