CloudHKA: a cryptographic approach for hierarchical access control in cloud computing

摘要: Cloud services are blooming recently. They provide a convenient way for data accessing, sharing, and processing. A key ingredient successful cloud is to control access while considering the specific features of services. The include great quantity outsourced data, large number users, honest-but-curious servers, frequently changed user set, dynamic policies, accessing light-weight mobile devices. This paper addresses cryptographic assignment problem enforcing hierarchical policy over data. We propose new scheme CloudHKA that observes Bell-LaPadula security model efficiently deals with revocation issue practically. We use encrypt so secure against servers. possesses almost all advantages related schemes, e.g., each only needs store one secret key, supporting set hierarchy, provably-secure collusive attacks. In particular, provides following distinct make it more suitable controlling data. (1) constant computation time accessing. (2) encrypted securely updatable can prevent revoked from decrypting newly previously Notably, updates be by using public information only. (3) legal attack. attack launched an authorized, but malicious, who pre-downloads needed ciphertexts in his authorization period. uses pre-downloaded future decryption even after he revoked. Note often small portion only, e.g. header-cipher hybrid ciphertext. (4) Each flexibly authorized rights Write or Read, both.