david gerad doesn't buy all the height. he's one of the most outspoken critics and skeptics of block chain technology. it's not very good as a payment system. this small claimant use case if you want to trade in things the government doesn't want you to trade in vets. david's polite way of saying illegal stuff in 2011, most of my talking to colleagues was saying 3 things here. so without the drugs pornography on sale, the silk road was a black market on the dock with, with buyers and sellers, use big coins to fly under the radar of the authorities. it had 1000000 uses until the f b. i showed up and shut it down. they called this guy for running it and confiscated the coins held in escrow by snatching his computer. and then they locked him away for life. no doubt crypto currencies can be a tool for criminal activity, but still on the bills, all the banking system. and let's not forget, the block chain is a public let you, that it's actually been quite useful for uncovering crimes. a former federal prosecutor named catherine