The development of IT in the last twenty years has affected each aspect of human life. People’s health and financial data are interconnected through the Internet. In order to allow a secure data exchange, sensible information have to be protected. For this reason, passwords must be non-reproducible and intrinsically linked to their owners. Nowadays there are different kinds of ID systems from finger prints to the simplest passwords. Are they a really secure way to protect sensitive data? Of course not. Actually, all these credentials could be stolen or replicated. However, each person has biometrical parameters different from one to another. One of them satisfies all our requirements: HEART SIGNAL. From this idea we have built a system which is able to use this signal as a password.