| 摘要 |
PURPOSE:To prevent 3rd party from pretending to be a mobile set having a correct identification number and uses a line while being exempted from the charge by allowing a base station to decode a ciphered identification data specific to a mobile set and received from the mobile set through the use of a decoding key by means of a decoding means so as to identify the mobile set thereby specifying the charging object. CONSTITUTION:A mobile set 10 is provided with a 1st storage means 16 storing an identification data specific to a mobile set, a 2nd storage means 12 storing the ciphered identification data specific to the mobile set and a ciphering means 22 ciphering a communication data to a base station 50 by means of the identification data stored in the 1st storage means 16 and specific to the mobile set. Then the mobile set sends the identification data ciphered and specific to the mobile set and the communication data ciphered by the cipher means 22. The base station 50 uses a decoding means 52 so as to decode the ciphered identification data received from the mobile set 10 and specific to the mobile set by using a ciphering key K1. Thus, it is prevented that a 3rd party monitors a communication message to recognize the information number illegally and the charging destination is specified without hindrance. |
