| 摘要 |
PROBLEM TO BE SOLVED: To prevent the unauthorized use of a program by a third party by ciphering deciphering key data outputted from an IC card by common key data and outputting them. SOLUTION: The cipher generation part 16 of the IC card generates the cipher generation information data (YB) of a prescribed length by a power remainder arithmetic operation in a power remainder arithmetic operation part, based on a random number (XB) generated in a random number generation part. The cipher generation information data (YB) are outputted through an IC card reader to a game machine body. Also, the cipher generation information data (YA) generated by a cipher processor 11 are outputted from a game machine as well and inputted to the power remainder arithmetic part of the IC card and the common key data (KAB) are generated by performing the power remainder arithmetic operation of the respective cipher generation information data (YA) and (XB) by the power remainder arithmetic part. Based on the common key data (KAB), the deciphering key data stored in a ROM part are ciphered in a ciphering arithmetic operation part. |
