Search

In recent years, the research on ciphertext-policy attribute-based encryption (CP-ABE) scheme design based on learning with errors (LWE) has been a challenging problem, and many researchers have made a lot of attempts at it. At EUROCRYPT 2021, Datta, Komargodski, and Waters proposed the first provably secure direct CP-ABE construction that supports NC 1 circuit access structures. Improving on their work, we propose a CP-ABE scheme. Technically, we use the new lattice two-stage sampling technique of Lai, Liu, and Wang (EUROCRYPT 2021) in the key generation phase instead of the extended trapdoor sampling technique. In this way, we obtain a CP-ABE scheme, which is at least as secure as the original scheme under the same conditions, and has a shorter ciphertext; we provide an innovative design idea for designing CP-ABE schemes only based on LWE, although this is only a partial theoretical work. [ABSTRACT FROM AUTHOR]

In recent years, the research on ciphertext-policy attribute-based encryption (CP-ABE) scheme design based on learning with errors (LWE) has been a challenging problem, and many researchers have made a lot of attempts at it. At EUROCRYPT 2021, Datta, Komargodski, and Waters proposed the first provably secure direct CP-ABE construction that supports NC1 circuit access structures. Improving on their work, we propose a CP-ABE scheme. Technically, we use the new lattice two-stage sampling technique of Lai, Liu, and Wang (EUROCRYPT 2021) in the key generation phase instead of the extended trapdoor sampling technique. In this way, we obtain a CP-ABE scheme, which is at least as secure as the original scheme under the same conditions, and has a shorter ciphertext; we provide an innovative design idea for designing CP-ABE schemes only based on LWE, although this is only a partial theoretical work.

In recent years, attribute-based encryption (ABE) provides a new idea to help researchers solving the problem of data privacy protection in cloud. But there are two issues in traditional ABE, the first issue is that the attributes in the access structures will be sent to users in cleartext together with the ciphertext. So a attacker has the opportunity to obtain some of the private information from the plaintext access structure. And the other issue is the traditional ABE scheme cannot revoke the users' illegal keys in an efficient way. To handle both of the above challenges, we come up with a large universe ciphertext-policy ABE (CP-ABE) scheme which supports partially hidden access structures (PHAS) and highly efficient key revocation at the same time in this paper. What's more, unlike most previous schemes, first our access structure is based on the expressive linear secret sharing scheme (LSSS) which supports both AND and OR gates in access formulas and second our scheme is built from the prime-order bilinear pairing groups. The comparison with other relevant works presents that our scheme is more comprehensive and efficient. Finally we rigorously prove and analyze that our scheme is selectively indistinguishable secure under chosen plaintext attacks (IND-CPA) in the random oracle model (ROM) and our access structure is really anonymous against off-line dictionary attacks. [ABSTRACT FROM AUTHOR]