Headquartered in Seattle, Dangerous Things and VivoKey Technologies use NFC and RFID technology to launch cryptocurrency wallets that can be implanted under the human skin to enable secure cryptocurrency transactions. "These wallets are hardware wallets for sending cryptocurrencies," according to officials. "Your phone app is your interface, but it doesn't have any private keys. Both the private keys and the actual signatures for bitcoin transactions or encrypted transactions are done in the chip." The implantable device, the Apex Flex, retails for $349. Founded in 2013 and 2017, respectively, Dangerous Things and VivoKey specialize in near field communication (NFC) and radio frequency identification (RFID) technologies that are custom-installed in the human body.