| 摘要 |
PROBLEM TO BE SOLVED: To make a memory card inexpensive by executing terminal authentication processing through the use of a random number calculated based on a random number generated by a terminal equipment so as to unnecessitate the providing of a random number generation circuit necessitating a chip area with complicated constitution on the IC chip of the memory card. SOLUTION: At the time of authenticating the memory card 1, a third random number 11 in a storage means 2 is used. The third random number 11 is calculated by a random number arithmetic means 15 based on first and second random numbers 9 and 10. The means 15 constitutes the third random number 11 by extracting a specific digit from a digit in a specific random number from the first and second random numbers 9 and 10. In addition, the means 15 constitutes the third random number 11 by replacing the arranging order of each digit in the first and second random numbers 9 and 10, shifting the digits in the first and second random numbers 9 and 10, executing numerical arithmetic between the first and second random numbers 9 and 10 or executing numerical arithmetic between the first and second random numbers 9 and 10 and a prescribed numerical value. Thereby a different random number is generated at every execution to prevent illicit use. |
