To preserve the context privacy, the health monitoring
system is organized by a trusted authority (TA). The system
model includes the registered patients, physicians, electric
health record (EHR) database in the monitoring server and TA,
as shown in Fig. 1. Patient Alice, after registering herself to TA,
can get the body sensor devices suitable to her, and then deploy
a BAN at home so that PHI can be collected and sent to the
EHR database and physicians.