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As a new revocation mechanism for identity-based encryption (IBE), server-aided revocable IBE (SR-IBE), firstly proposed by Qin et al. in 2015, achieves remarkable advantages over previous identity revocation techniques. In this primitive, almost all of workloads on the users (i.e., receivers) side can be delegated to an untrusted server which does not possess any secret information, and the users can compute short-term decryption keys alone at any time period without having to communicate with either the private key generator (PKG) or server. In 2016, Nguyen et al. creatively presented the first lattice-based SR-IBE by adopting a 'double encryption' mechanism to enable smooth interactions between the sender and the server, as well as between the server and the receiver, while ensuring the confidentiality of encrypted messages. In this paper, inspired by recent work on a new treatment of the identity space and the time period space, we simplify the first construction of lattice-based SR-IBE provided by Nguyen et al., and remove some items from the public parameters and the master secret key. In particular, our scheme is more efficient by reducing the workloads of PKG, the server, the sender and the receivers, simultaneously. At the heart of our new design is a tool called 'leveled ciphertexts' that enables constant ciphertexts and simplified encryptions, not linear in the length of user identities and without a burdensome double encryption technique, which serves as a more effective solution to the challenge in turning the pairing-based instantiation of SR-IBE into the world of lattice-based cryptography, and based on the hardness of learning with errors (LWE) problem, we prove that our new scheme is selectively secure in the standard model. © 2022, The Author(s), under exclusive license to Springer Nature Switzerland AG.
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ISSN: 0302-9743
Year: 2022
Volume: 13600 LNCS
Page: 71-87
Language: English
0 . 4 0 2
JCR@2005
Cited Count:
SCOPUS Cited Count: 1
ESI Highly Cited Papers on the List: 0 Unfold All
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30 Days PV: 2
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