Any serious Bitcoin user will preach the benefits of cold storage: keeping the bulk of your bitcoins offline somewhere, like on an encrypted USB stick, or even printed on a piece of paper. The idea is that by keeping that data offline, it’s far less susceptible to being hacked. So, the theory goes: what could be safer than keeping it inside your own body? For the last 10 days, Martijn Wismeijer, a Dutch entrepreneur and Bitcoin enthusiast, has lived with an NFC chip embedded in each hand. 

“Mr. Bitcoin” will never forget where he left his wallet. It’s implanted under his skin. The Amsterdam-based Bitcoin entrepreneur, whose real name Martijn Wismeijer, turned himself into a real-life cyborg by having a miniature digital communications chip implanted in his hand. Wismeijer and his compatriots got tiny NFC chips injected into their hands. NFC, which stands for near-field communications, is the same type of technology built into the Apple Pay digital payment system and numerous Android devices. NFC is a short-range wireless system that allows devices to send data back and forth, enabling the user to make mobile payments or send commands to other smart devices. The chip that “Mr. Bitcoin” used was developed by a company called Dangerous Things. According to the company’s Indiegogo campaign, its inventor, Amal Graafstra, had the first model implanted into his own hand by a surgeon in 2005, and got a second upgraded model injected a couple of months later using a pet chip injector assembly. Wismeijer used the same type of injector to have the miniature device slipped under his skin.