| 摘要 |
Disclosed are a method for revoking data access and a cloud service system using the same capable of reducing a processing load in performing a revocation function. The method for revoking the data access like this comprises the steps of: storing a primary cryptogram encrypted to enable only a user group, who has access permission, to decrypt; cyclically updating a revocation list including target information of revoking the access permission to the user group and storing the revocation list at a security management server; making the security management server provide the updated revocation list to the cloud service server; and converting the first cryptogram into a secondary cryptogram to making it impossible to decrypt a revocation target, included in the updated revocation list, at the cloud service server. By this means, the present invention cyclically updates the revocation list and generates the secondary cryptogram, thereby may reduce the processing load in performing the revocation function. [Reference numerals] (10) Data owner system; (20) Cloud service server; (30) Security management server; (AA) First user; (BB) Second user |
