A research paper speculating Bitcoin's creator may have transferred US$60,000 to the Silk Road marketplace has been dispelled, as the account holder in question came forward on Tuesday, denying he is the mysterious Satoshi Nakamoto.
Dustin Trammell, a security researcher who is CEO of the vulnerability marketplace ExploitHub, wrote in a blog post that the Israeli researchers failed in their analysis, which was subject to blistering criticism from the bitcoin community.
"I hope this puts to rest any further speculation regarding whether or not I am Satoshi Nakamoto and whether or not I have had any involvement with the Silk Road," Trammell wrote. "I am not and have not."
The paper was written by Adi Shamir and Dorit Ron of the Weizmann Institute of Science in Israel. Shamir is a noted cryptographer credited with co-creating the RSA encryption algorithm, which is widely used to protect corporate data.
In an email to IDG News Service, Shamir defended their work, writing that "we were extremely careful in our choice of words and repeatedly stressed that we have no proof."
But later on Wednesday, Shamir wrote in an email that after reading Trammell's blog post, the paper would be revised.
In four paragraphs at the end of their 13-page paper, Shamir and Ron described a 1,000-bitcoin transaction, worth around $60,000 at the time, sent in March. It came from a bitcoin account established just a week after the system launched in 2009, a so-called "founder" account.
Many of the early bitcoin accounts are believed to be controlled by the person who supposedly created Bitcoin, who used "Satoshi Nakamoto" as a pseudonym.
Their analysis claimed the virtual currency eventually ended up in another account belonging to DPR, short for "Dread Pirate Roberts," who controlled the Silk Road marketplace. U.S. federal prosecutors allege DPR is 29-year-old Ross William Ulbricht, who faces murder-for-hire, narcotics trafficking and computer hacking charges.
Trammell wrote that he sent the 1,000 bitcoins to Mt. Gox, the Tokyo-based bitcoin exchange, "for trading purposes."
"Mt. Gox should be able to easily confirm that they indeed control this destination address," he wrote.
Trammell's explanation is "completely believable, and thus we no longer believe that the very early founder account we identified in the full bitcoin transaction graph belongs to Satoshi Nakamoto," Shamir wrote. "We will revise our paper accordingly."
Although the researchers hedged on the claim, their wording in the paper was strong enough to suggest that they might have spotted something stunning.
"The short path we found suggests (but does not prove) the existence of a surprising link between the two mysterious figures of the Bitcoin community, Satoshi Nakamoto and DPR."
The paper touched off a firestorm of criticism on Reddit. By studying Bitcoin's public ledger of transactions, called the "blockchain," commentators quickly cast doubt on it.
"The paper is complete crap," wrote Jeff Garzik, a software engineer who has extensive experience with Bitcoin, in an email to IDG.
Bitcoin's blockchain is public and transparent, showing all transactions since the system was launched. But following the flow of bitcoins can get tricky, especially if "mixing" services are used, which create spider web-like transaction trails.
Gavin Andresen, chief scientist for the Bitcoin Foundation, said the FBI likely has deeper information on the Silk Road's transactions, some of which may not have been illegal.
"If I was an evil mastermind designing a bitcoin mixing service, I would certainly try to mix in perfectly innocent bitcoin transactions to try to hide the illegal activity," he wrote in an email.
Shamir said he and Ron followed well-established approaches in social science research for describing correlations, clearly stating "what is a scientific fact and what is an unproven conjecture."
But controversy over those last four paragraphs unfortunately undermined one of the paper's most interesting conclusions: that the FBI has only seized about 22 percent of the 633,000 or so bitcoins the Silk Road collected in commissions from facilitating contraband sales.
In his email, Shamir said Bitcoin enthusiasts do not like analyses that do "not fully support their beliefs." He also took a swipe at the media.
"It was the media reporting, and not our paper, which made this side issue a cornerstone of our paper," he wrote.
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