earticle

영어

Attribute-Based Encryption provides an encrypted access control mechanism. A user applies and obtains a private key that is associated with various attributes of the applicant. A secret message is encrypted with an access control policy tree representing a logical combination of different attributes. Only the users whose attributes satisfy the policy tree can decrypt the message. There are many scenarios that require dynamic attributes. Whenever a dynamic attribute updates, a new key is regenerated and issued even if there are hundreds of attributes involved in the key. This is not efficient since the cost of generating new private key is proportional to the number of attributes associated with that private key. To resolve the efficiency problem, this paper introduces the concept of Dynamic Attribute Based Encryption, a key revocation mechanism, which is necessary to prevent a user from keeping a private key with expired attributes. We show that the new concept improves the efficiency of the encryption scheme and helps us develop a new trust management method.