Jonathan LeBlanc, PayPal’s global head of developer evangelism, claims that these devices could include brain implants, wafer-thin silicon chips that can be embedded into the skin, and ingestible devices with batteries that are powered by stomach acid.

These devices would allow “natural body identification,” by monitoring internal body functions like heartbeat, glucose levels and vein recognition, Mr LeBlanc told the Wall Street Journal.

Over time they would come to replace passwords and even more advanced methods of identification, like fingerprint scanning and location verification, which he says are not always reliable.