| 摘要 |
PROBLEM TO BE SOLVED: To prevent a cipher key from being wrong stored in a key management device other than the normal one by adding a condition to permit the storage of the cipher key in another key management device when the cipher key is transported to the above key management device and then storing the cipher key in another key management device only when the permitting condition is satisfied. SOLUTION: A key which is enciphered by a 1st key management device is acquired from an input/output device 7, and a symmetrical key is acquired from a symmetrical key generation part 5. The key enciphered by the 1st key management device is decoded by the symmetrical key. This symmetrical key is equal to a symmetrical key that is generated by the 1st key management device and can be decoded. The relevant point of time is acquired from a time holding part 8 and compared with the decoding enabling time included in the data which decoded the enciphered key. If the acquired time is kept in a decoding enabling range, a pair of open keys included in the decoded data are stored in an open key storing part 2. The decoded pair of open keys are stored in the part 2 and then transported to a 2nd key management device from the 1st one.
|
