Shorter Decentralized Attribute-Based Encryption via Extended Dual System Groups

Abstract

Decentralized attribute-based encryption (ABE) is a special form of multiauthority ABE systems, in which no central authority and global coordination are required other than creating the common reference parameters. In this paper, we propose a new decentralized ABE in prime-order groups by using extended dual system groups. We formulate some assumptions used to prove the security of our scheme. Our proposed scheme is fully secure under the standard -Lin assumption in random oracle model and can support any monotone access structures. Compared with existing fully secure decentralized ABE systems, our construction has shorter ciphertexts and secret keys. Moreover, fast decryption is achieved in our system, in which ciphertexts can be decrypted with a constant number of pairings.

A Traceable and Revocable Multiauthority Attribute-Based Encryption Scheme with Fast Access

“…Inspired by [18,20], we adopt a hash function H to map user identities to the elements in group G 2 . Unlike with [18,20], we use a CA to personalize the identity key for each user and the AAs to generate the corresponding attribute keys, so our construction can achieve multiple authorities and the AAs cannot get the user decryption key. Furthermore, we employ a full signature scheme [32] to realize traceability.…”

“…More specifically, the CA injects the signature of the user identity into the user identity key and traces the user by his decryption key. We now present our T-MA-CP-ABE construction based on [18,20], in which each attribute authority AA j manages an attributes set S j .…”

“…In this section, we first prove that our T-MA-CP-ABE scheme is adaptively secure based on the SXDH assumption by a reduction to the underlying scheme in [20]. More specifically, we assume an adversary A breaks our T-MA-CP-ABE scheme in the random oracle model with advantage ε; then, we build a simulator B that breaks the scheme [20] in the random oracle model with advantage ε. en, we prove our T-MA-CP-ABE scheme is fully traceable based on the q-SDH assumption by a reduction to a signature scheme [32]. More specifically, we assume an adversary A breaks our T-MA-CP-ABE scheme in the traceability game; then, we build a simulator B that breaks the signature scheme [32] under an adaptive chosen message attack.…”

“…Based on [18], Cui and Deng [19] presented a revocable MA-ABE that achieves attribute revocation. Zhang et al [20] presented a shorter MA-ABE where a ciphertext can be decrypted with a constant number of pairing operations. Wang et al [21] constructed a MA-ABE scheme from the LWE assumption.…”

An Approach Enabling Various Queries on Encrypted Industrial Data Stream

“…Encryption. Brent Waters firstly introduced a methodology to build adaptively secure IBE and HIBE which is dual system encryption [35], and a lot of work relied on this powerful proof tool [33,[36][37][38]. In dual system encryption schemes, there are two forms of ciphertext and key: normal and semifunctional.…”