Research On Critical Technology Of Attribute-Based Encryption In The Cloud Computing Environment

The coming of the cloud computing has attracted more and moreenterprise and individuals to outsource their data to cloud storage service.However, the security issue brought by outsourcing cannot be ignored. Asdata are not stored in local place and cloud servers cannot be completelytrusted, whether cloud users have enough control on their own data, how toprotect data privacy and share data in an efficient method, all of theseproblems are needed to be solved.We propose a scheme named an efficient attributed based encryptionwith hidden policy, to make cloud users’ data be stored and shared safely inuntrusted cloud servers. Compared with the previous schemes, we optimizethe length of ciphertexts and the decryption time, especially the pairingcalculations, to a constant level, which greatly improves the efficiency,moreover, the access structure is hidden within the ciphertext to furtherprotect the privacy of users. This scheme is proven fully secure under thestandard model, which is stronger than most selective secure model.Based on the original scheme, this thesis also proposes an extendedscheme, which enhances the flexibility of the access structure, expands theapplication scope, and still keeps both the high efficiency and anonymityreserved. Besides, we implement a demo system of our scheme by using theopen source code library. We do efficiency test experiments of our corealgorithms for comparisons with previous schemes, the results verify thatour scheme is feasible and effective in reality.