Ask Alan Lane. In October, the president and CEO of Silvergate Bank in La Jolla, Calif., was up in Sacramento for a roundtable convened by the California Bankers Association and the state's Department of Business Oversight. Reading a laundry list of about a dozen issues on the department's radar, Commissioner Jan Lynn Owen mentioned Bitcoin — the Internet currency, payment system and technology that's been grabbing headlines, igniting controversy and inspiring innovation across the globe. Lane pricked up his ears, in part because the $616 million-asset Silvergate had been in discussions about banking a Bitcoin startup.