| 摘要 |
The tariff is recorded within the card, enabling tariff computation without reference to the network itself.- DETAILED DESCRIPTION - The mobile telephone uses a prepaid card, with the card (18) containing rate fixing parameters used by the mobile telephone (16). This allows computation of the amounts to be debited against the counter which records the number of prepaid units held by the card. The message exchanges between the mobile phone and the card are encrypted to ensure the security of transactions, preferably using a cryptographic certificate. The mobile phone also includes a memory for storing the rate parameters for computation, these rates having been read from the card. The cryptographic process used for security is initiated by a random number provided by the telephone network (14) |
