Attribute-based signature is an attractive cryptographic primitive and finds broad applications in many fields. Existing attribute-based signature schemes deal with attributes in the way of “with” or “without,” and there is no attribute-based signature scheme that supports comparing attributes. Using the 0-encoding and 1-encoding, we propose an access structure algorithm and an attribute expansion algorithm, enabling the attribute-based signature scheme to effectively deal with the comparative attributes. Then, we propose a signature-policy comparable attribute-based signature scheme using the proposed expansion algorithms. The proposed scheme is existentially unforgeable under the computational Diffie–Hellman exponent (CDHE) assumption and achieves privacy in the sense of information theory. Theoretical analysis and simulation experiments show that our method is practical and has significant advantages in storage and computation overhead compared with the trivial way. Comparable attribute-based signature dramatically expands the application scenarios of attribute-based signature.
Patient location sharing is an important part of modern smart healthcare and mobile medical services. Blockchain has many attractive properties and is suitable for managing patient locations in telecare medical information systems (TMIS). Recently, Ji et al. proposed a blockchain-based multilevel privacy-preserving location sharing (BMPLS) scheme for TMIS. In this paper, we show that Ji et al.’s BMPLS scheme does not achieve confidentiality and multilevel privacy-preserving. An adversary outside the system can use an ordinary personal computer to completely break the system within a dozen hours and obtain the location of any patient at any time. The adversary inside the system can use an ordinary personal computer to obtain the location of the designated patient within tens of seconds. Using salting technology, we propose an improved BMPLS scheme to fix our attacks. We also optimized the BMLS scheme to make it correct and executable. The security analysis shows that the improved BMPLS scheme achieves decentralization, untamperability, confidentiality, multilevel privacy-preserving, retrievability, and verifiability. The simulation shows that the improved BMPLS scheme is practical, the computational overhead of the location record phase is within 10 ms, and the computational overheads of the location sharing and location extraction phases are both within 30 ms.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.