As another example, a content right management system that determines whether or not the user has a legitimate right based on a result of specifying a person using any of the personal authentication devices described above may be provided. The system may include, in addition to the personal authentication device, means for determining whether or not the user has a legitimate right to content based on a specification result output from the personal authentication device, and means for providing a service such as content only in the case where the user has a legitimate right as a result of the determination.

As yet another example, a voice communication control system that performs voice communication only for a specific person based on a result of specifying a person using any of the personal authentication devices described above may be provided. The system may include, in addition to the personal authentication device, means for controlling voice communication such as permitting only a designated person to perform voice communication based on a specification result output from the personal authentication device. There is a possibility that voice communication is eavesdropped unless it is, for example, encrypted. Even when the voice communication is encrypted, there is a possibility that the voice communication is eavesdropped through leakage, theft, or the like of the cipher. For example, by encrypting voice using acoustic property extracted for each person by the personal authentication device, voice communication that has low possibility of leakage or theft can be realized. Moreover, for example, voice communication by secret key/public key cryptography may be realized using, as a secret key, acoustic property extracted for each person by the personal authentication device. Communication provided by the system is not limited to voice communication, and may be, for example, data communication.