Research Article
Enhanced Dual-Policy Attribute-Based Encryption for Secure Data Sharing in the Cloud
Table 1
Function comparison with some related work of DP-ABE.
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Regarding time performances, Guillevic [29] reported that for the same 128 bit security, pairings are 254 times slower in composite-order than in prime-order groups, and exponentiations are also about 1014 times slower. Moreover, composite-order group elements are about 12 times larger than prime-order group elements. Although there exist techniques [30] to convert pairing-based schemes from composite-order groups to prime-order groups, there is still a significant performance degradation due to the required size of the special vectors [16]. In small universe constructions, the size of the attribute space is polynomially bounded in the security parameter and the attributes are fixed at setup. Moreover, the size of the public parameters grew linearly with the number of attributes. In large universe constructions, on the other hand, the size of the attribute universe can be exponentially large, which is a desirable feature [16]. Encryption and key generation in single-policy modes are pretty flexible features. When a DP-ABE scheme has been already set up, it can also be used in KP-ABE or/and CP-ABE settings. If one ignores subjective (resp. objective) attributes, the DP-ABE scheme becomes KP-ABE (resp. CP-ABE). This flexibility provides great convenience since the same ciphertext (or/and the same secret key) can be used for all three variants of ABE. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||