A Fully Secure Attribute Based Broadcast Encryption Scheme

Besides traditional functionality of broadcast encryption, attribute based broadcast encryption (ABBE) provides more flexible assess control mechanism over encrypted data. In this paper, a ciphertext-policy ABBE (CPABBE) scheme is proposed. In such scheme, user’s private key is attached with attributes and an index while ciphertext is associated with an access structure and a broadcast set. A key will decrypt a ciphertext if and only if its attributes satisfy the access policy and its index is included in the broadcast set. Our construction is based on composite order bilinear group and its security can be reduced to three static intractable assumptions through famous dual system encryption methodology in fully secure model. Some application aspects of our ABBE scheme and comparisons between such scheme and existing ABBE schemes are also provided.