| 摘要 |
PURPOSE:To prevent the periodicity of a generated random number and to improve safety by generating the random number with the use of time information from a clock means in a system to mutually recognize an IC card and a terminal with the decoding of the random number transmitted between the IC card and the terminal and the returning it. CONSTITUTION:When a starting signal is transmitted to a CPU 27 of the IC card set with a terminal, clock information is tempolarily stored from a second clock circuit 323 to a reading data memory 30, supplied to a random number generating part 37, and random number information is generated by key information K. The random number information is decoded to the original time information by using the same key information K as the key information returned to the terminal and used in the random number generating part 37, and returned to the IC card. By receiving it, the CPU 27 compares and collates the decoding information with the time information in a data memory 30, communication is carried out, and it is judged whether or not the IC card is more on the terminal side. In the same way, on the terminal side, the communication is carried out, and whether or not the IC card is more on the IC card side is judged. |
