| 摘要 |
<P>PROBLEM TO BE SOLVED: To allow a portable terminal device to use an encryption key without communicating with an authentication server, and prevent the encryption key from leaking when a terminal is lost or stolen. <P>SOLUTION: An encryption key 102 is stored in a non-volatile memory 404 before a portable terminal device 101 is switched on. The encryption key 102 is moved from the non-volatile memory 404 to a volatile memory 405 by an encryption key protection unit 401 when the portable terminal device 101 power supply is turned on. A user authentication unit 403 performs user authentication. If the user authentication is failed, the encryption key protection unit 401 erases the encryption key 102 from the volatile memory 405. <P>COPYRIGHT: (C)2012,JPO&INPIT |
