And he could be reading your ecg continuously in real time when he wants and there is an anomaly or a problem , then he will just download the data from the sensor the last day 's worth of information , check if this was an anomaly or whether there was a consistent problem .
As a proof of concept , lin 's system currently takes the user 's ecg reading from each palm once , and a key based on that reading is stored and used for all later decryptions .