| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To share data in a group while suppressing the increase of load due to encryption/decryption processing. <P>SOLUTION: An encrypted data key obtained by encrypting a data key K for encrypting data DT by a public key KPu1 for a group is previously stored, an encrypted group secret key E (KPu1, Kg1) obtained by encrypting a secret key of the group by a public key of a user belonging to the group is previously registered, and when the user belonging to the group intends to refer to the data DT, the encrypted group secret key E (KPu1, Kg1) is decoded by a user's secret key Ku1 to acquire the group secret key Kg1, the encrypted data key is decoded by using the group secret key to acquire the data key K and the encrypted data E (K, DT) are decoded by using the data key K to obtain the plain data DT. <P>COPYRIGHT: (C)2007,JPO&INPIT</p> |
