In a plurality of described embodiments, various modules of an application for a client device may operate to enhance personal security for an individual user, as well as public safety in general. In one embodiment, monitoring classes are used to collect monitoring data from at least one PersistenceUnit and at least one PersistenceContext associated with the PU of an application the uses an in implementation of a Java Persistence Application Programming Interface. The reproducing unit carries out mutual authentication between itself and the removable medium and, when the authentication is successful, acquires rights information recorded on the removable medium to thereby decrypt the encrypted content item delivered by the content server on the basis of the rights information, and subject the decrypted content item to streaming reproduction.