| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a portable storage medium capable of preventing an encryption key stored in the portable storage medium, such as an IC card, from being illegally decrypted by automatically preventing the encryption key from being used and enabling the encryption key to be switched to another encryption key when the predetermined number of times of using the encryption key is exceeded. <P>SOLUTION: The portable storage medium that can store the encryption key and execute encryption processing using the encryption key has: a storing means for recording the number of times of executing encryption processing using the encryption key; and a usage inhibiting means for inhibiting the usage of the encryption key in accordance with the number of executing times, wherein: the storing means stores the limited numbers of times of using a plurality of kinds of encryption keys respectively in advance; and the usage inhibiting means has a function of inhibiting the usage of the encryption key when the number of executing times exceeds the limited number of using times by comparing the number of times of executing encryption processing using the encryption keys stored in the storing means with the limited number of times of using the encryption keys. <P>COPYRIGHT: (C)2009,JPO&INPIT |
