A Practically Optimized Implementation of Attribute Based Cryptosystems

Attribute based encryption (ABE) has been applied to many applications nowadays [1][2] and it effectively achieves a fine grained access control. Even the encryptor needs only one encryption operation, and all the decryption operations are distributed to the receiver´s end, the computational cost of encryption is still impractical when there is a large amount of encryption with different access structures. In this paper, we examine existing techniques that optimize the decentralized attribute based encryption scheme [3], such as a better construction of e Linear Secret-Sharing Scheme (LSSS) matrix, pre-processing of scalar multiplication and pairing, multi-pairing and so on. We proposed the deployment of offline pools to improve the real-time operations. We proposed the method to construct offline pools and designed algorithms to achieve better hitting rate of offline pool topples. We evaluated the optimization techniques, the result shows that there is a 45 times of performance improvement in the encryption (6-8 times for the decryption) after we applied all the real-time optimization techniques mentioned in our paper. With deployment of the offline pools, the optimization can be improved at least 100-200 times than without offline pools.