Fully Secure Unbounded Revocable Key-Policy Attribute-Based Encryption Scheme

摘要

Attribute-based encryption (ABE) is a promising cryptographic primitive which can provide fine-grained access control over encrypted data. Providing an efficient revocation mechanism for ABE scheme is crucial since users' credentials may be compromised or expired over time. Existing revocable ABE schemes in the literature are not satisfactory: (1) they are bounded in the sense that the size of the public parameters depends linearly on the size of the attribute universe; (2) they are only proved to be selectively secure in a prime order bilinear group setting or to be fully secure in a composite order bilinear group setting. In this paper, we present a unbounded revocable key-policy ABE scheme from prime order bilinear groups based on dual pairing vector space technique. The proposed scheme is proved to be fully secure under the DLIN and CDH assumptions in the standard model by adopting the dual system encryption methodology over dual pairing vector space. Compared with previous revocable key-policy ABE schemes, our proposed scheme is more efficient in terms of the size of ciphertext and private key, and the cost of encryption and decryption.