Judge Rejects Bitcoin Expert Testimony in Silk Road Trial

​The judge in the trial against Ross Ulbricht, the accused mastermind behind internet drug market Silk Road, issued an order Monday to block two witnesses the defense sought to call, including a Bitcoin expert and a computer and internet security expert.

Judge Katherine Forrest explained her decision to preclude the testimony of these witnesses in a strongly worded order filed in the court docket, outlining apparent missteps from the defense in the trial, including that its announcement of expert witnesses did not comply with with Rule 16, which requires the defendant to sufficiently disclose the substance of the expert witness testimony in advance.

"As of the start of trial, the defense had failed to disclose its intention to call any expert witness," Forrest wrote. "Proper expert disclosures are not a mere technicality with which compliance may be made or not—they are required by Rule 16 of the Federal Rules of Criminal Procedure."

The defense announced on Friday that it planned to call Andreas Antonopoulos, a coder and Bitcoin entrepreneur, and Steven Bellovin, a computer science professor at Columbia University, as expert witnesses in the trial.

According to the filed documents, Bellovin was called to testify about "General principles of internet security and vulnerabilities; the operation of timestamps in UNIX-based operating systems; the import of some lines of PHP code provided to defense counsel in discovery; forensic memory analysis; general principles of public-key cryptography; general issues related to linux-based operating systems, including security, implications of various linux kernel versions, differing methods of software installation, etc."

Antonopoulos was to testify about "the origins of Bitcoin and the various purposes and uses of Bitcoin."

The prosecution filed a request to preclude both of these testimonies, saying the notice of Bellovin's expert testimony did not comply with Rule 16, as it was announced with too little notice, and with too little detail as to what he would testify about.

"The notice provided by the defendant regarding Mr. Bellovin is vague, open-ended, and plainly insufficient under the Federal Rules of Criminal Procedure, as it merely provides a list of topics the defense seeks for Mr. Bellovin to testify about, without indicating anything regarding the 'opinions' plans to offer on those topics, or 'the bases and reasons for those opinions,'" the letter to Judge Forrest said. "Merely identifying the general topics about which the expert will testify is insufficient; rather, the summary must reveal the expert's actual opinions."

In its motion to preclude the testimony of Antonopoulos, the prosecution said the topics he planned to testify about were not relevant to the case.

"The first two subjects that the defense intends to have Mr. Antonopoulos testify about are 'the origins of Bitcoin' and 'the various purposes and uses of Bitcoin.' Neither topic is relevant to this case," the letter said. "Presumably, the defense plans to elicit testimony from Mr. Antonopoulos that Bitcoin has a legitimate origin and legitimate purposes and uses. However, neither point is in dispute here. None of the Government's witnesses have testified to the effect that Bitcoin is inherently illegitimate; indeed, both Special Agent DerYeghiayan and former Special Agent Yum specifically testified, on direct, that using Bitcoins is not illegal in and of itself."

With the expert witnesses precluded, the defense was left with its five character witnesses and one expert witness. Three of the character witnesses were called Monday, all old friends of Ulbricht who knew him from childhood and testified to his "peacefulness and non-violence." Ulbricht told the judge on Monday he will not testify, but he is allowed to make an application to testify if he changes his mind.

"Ross has a good reputation," Daniel Davis, a 30-year-old employee of the city of Austin who has known Ulbricht since middle school testified. "He is one of the most peaceful people I know."

Also on Monday, the government wrapped up its final witness, Brian Shaw, a government contractor who analyzed the Silk Road servers. He laid out the amounts of drugs sold on Silk Road, testifying that between January 2011 and October 2013, there were more than 1.5 million transactions on Silk Road, amounting to about 9.9 million BTC, or nearly $214 million in US dollars, according to the government's conversion.

The prosecution and defense are expected to make their closing arguments Tuesday, and the jury could begin its deliberation as early as Wednesday. Motherboard will continue to cover the trial, so check back here for updates.