Multi-authority Attribute Based Encryption with Attribute Revocation

Multi authority attribute based encryption solve a completely trust problem about a single authorization center, make the data owner control fine-grained data and resist collusion attack. But in the practical attribute revocation needs a lot of calculation. Adding the user revocation list into cipher text implements the user revocation. Through agent re-encryption technology, decryption outsourcing technology and time division revocation re-vocation, we implement attributes revocation satisfying the forward security and backward security on the basis of the effective fine grained, meanwhile reducing the computational overhead when the attribute is revoked.