http://www.forbes.com/sites/valleyvoices/2015/01/15/how-prosecutors-might-nail-ross-ulbricht-using-the-supposedly-anonymous-bitcoin/When the FBI seized the Silk Road server and the associated bitcoin wallets, they didn’t just gain the ability to move the bitcoins, they also gained an index into history. The private keys contained in this file can generate a near infinite universe of distinct public addresses, but capturing the private key enables computing all these addresses. This acts as an index into the blockchain, the public ledger which records every bitcoin transaction. By seizing the wallet, the FBI now knows every bitcoin transaction involving the Silk Road wallets: payments sent, payments received, and even internal transactions designed to confuse outside analysis.
