A key information issuing device (1, 1A, 1B) issuing key information to a key information retaining device (2, 2A, 2B) includes an authentication module (14, 3) authenticating an issuer of the key information, an output module (13) outputting the key information to the key information retaining unit,...http://www.google.com.tw/patents/US7561695?utm_source=gb-gplus-share專利 US7561695 - Key information issuing device, wireless device, and medium
