Attribute-Based Certificateless Cryptographic System

As an extension of identity-based encryption scheme, attribute-based encryption scheme also has the key escrow problem. Multi-authority attribute-based encryption schemes are principal solution, but it is at the cost of the introducing extra infrastructure and communication. This paper introduces the concept of attribute-based certificatless encryption system (ABCE), which is a new approach to mitigate the key escrow problem in attributebased encryption scheme. In ABCE, the user can choose his own secret key that the KGC cannot obtain. In contrast to attribute-based encryption scheme under multiple authorities, our approach needs less extra cost. Following, we give a generic construction and an improvement in the efficiency.