| 摘要 |
PROBLEM TO BE SOLVED: To safely store transaction in a detachable medium, and to access the transaction by enciphering transaction data and alphanumeric character keys, generating recording constituted of the enciphered data and storing the data in a POS system. SOLUTION: The POS terminal of a POS terminal 100 or the like transmits a command to a medium stored by a customer such as a smart card 131 and starts receipt session. At that time, a series of parameters for selecting a proper random number generator, encipherment algorithm and a proper key for a specific receipt session can be included. Then, the medium stored by the customer generates one block of customer random data, enciphers the block of the customer random data by the selected key and the algorithm, and stores the customer random data and the enciphered customer random data in the medium. The medium stored by the customer transmits the data to the POS terminal constituted of the block of a command state indicator, a customer identifier and the customer random data and the block of the enciphered customer random data. |
