| 摘要 |
PURPOSE:To generate an enciphering key which is hard to be enciphered by generating random numbers constituting an enciphering key by utilizing data which are stored in memory of an IC card and change whenever a card is used. CONSTITUTION:Transmission data M which are inputted through a keyboard 15 and have security are enciphered through an enciphering circuit 51 and turn out an enciphered text F(M,R1). It is supplied to the receiving side together with a discriminating code outputted from an IC card 31T and random numbers E outputted from a random number generator circuit 52. The random number E is read out from a random number memory 53 in accordance with the specified address from an address setting circuit 54, and an address from the circuit 54 is generated by initial address data RL outputted from the card 31T at the transmitting side. The data RL are the final enciphering key R1 through which an enciphered text is transmitted by utilizing the card 31T and has been stored in memory of the card, and the initial address varies at every time. Thus fixation of the random number generation can be prevented and an enciphering key which is hard to be deciphered can be generated. |
