Ciphertext-Policy Weighted Attribute Based Encryption for Fine-Grained Access Control

In the cipher text-policy attribute based encryption scheme, the private key hold by user is associated with a set of attributes while the data is encrypted with an access structure defined by the data provider. In the most proposed schemes, the characteristics of attributes are treated in the identical level. In the real circumstance, the importance of each attributes is always different. In this paper, we propose a scheme called cipher text-policy weighted attribute based encryption (CP-WABE) while the attributes have different weights according to their importance. The CP-WABE scheme is proved to be security under the decision l-Expanded bilinear Diffie-Hellman exponent (l-Expanded BDHE) assumption, which can be considered as the generalization of traditional CP-ABE scheme when all attributes have equal weight.