METHOD AND DEVICE FOR MANAGING SECRET KEY OF OPEN KEY CODE CIPHER

摘要

PROBLEM TO BE SOLVED: To allow reproducing a secret key even when an individual portable device is lost or broken by inputting partial secret keys from persons who have an interest with the user of the individual portable device and generating the secret key. SOLUTION: Partial secrets which are the partial secret keys constituting the secret key and managed by the persons who have an interest with the user of the tamper-resisting individual portable device 55 are inputted to the device 55 from all of the said interested persons individually. Then the secret key is generated in the device 55 from the inputted partial secret keys, and stored in a storage area 533 in the device 55 out of which the secret key can not be read to the device 55. Further, the secret key stored in the area 533 is used for a composition process and a signature process only in the device 55.