Tim Draper, sole winner of an auction last week of 30,000 bitcoins by the U.S. Marshals Service, called the sale a vote of confidence by the government in the nascent crypto-currency. The well-known Silicon Valleyinvestor partnered with Palo Alto-based Vaurum, which facilitates over-the-counter bitcoin trading, for the sale but would not discuss how much he paid. Draper, a major backer of Vaurum, will partner with the startup to use the coins as a liquidity source for Vaurum's trading platforms in emerging markets, Draper told reporters in Palo Alto on Wednesday. The bitcoins, a virtual currency that is "mined" by computers solving complex algorithms, were seized last year by the Marshals Service in a crackdown on illegal online activity. Acceptance of bitcoin has been growing as more merchants allow customers to pay for goods and services with the currency. The U.S. Marshals Serviceauctioned off 29,655 bitcoins at an estimated worth of about $18 millionin an online, sealed-bid auction that drew more than 40 bidders, including a number of well-known players in the crypto-currency. Terms of the sale have not been disclosed, but the success gives the virtual currency more legitimacy as a means of exchange. The bitcoins auctioned off were part of 144,000 bitcoins seized in October in a raid on Silk Road, an Internet black-market bazaar that authorities said had been used for illegal drug transactions and other goods. A spokeswoman for the U.S. Marshals Servicesaid it will not conduct another auction of bitcoins unless there is a court order for the agency to do so.