To address the demand for fine-grained access control in Internet of Things (IoT) data sharing, attribute-based encryption (ABE) has emerged as a critical solution. Nevertheless, the computational overhead inherent in ABE poses a major challenge for its direct deployment on resource-constrained IoT devices. Data storage and sharing through centralized cloud may be interrupted due to cloud server failures. Additionally, if user attributes cannot be revoked, some users who should have had their data access rights canceled will still be capable of accessing the data. To solve these problems, we propose a multi-authority attribute-based data sharing scheme that combines blockchain to construct a secure and trusted data sharing environment, while supporting efficient attribute revocation. We reduce the computational burden during the online encryption phase through online/offline encryption, while introducing outsourced decryption to lessen the computational overhead of user decryption. Our scheme supports the tracing of key abusers and attribute revocation for users. Furthermore, by interplanetary file system (IPFS), we reduce on-chain storage burden, and by interplanetary name system (IPNS), we address the difficulty of logically deleting old ciphertexts when updating ciphertexts. Security analysis shows that our scheme exhibits static security, and experimental results demonstrate that our data sharing scheme exhibits excellent efficiency and practicality.

Digital Twins (DTs) generate vast sensitive data, demanding secure, dynamic, and fine-grained access control. While Ciphertext-Policy Attribute-Based Encryption (CP-ABE) offers such control, its inherent computational overhead, static nature, and the need to trust outsourcers for complex operations often limit its practical application in evolving DT environments. In this paper, we proposed an Outsourced Attribute-Based Encryption Scheme with Verifiable Policy Update and Dynamic Attributes (OABE-VPUDA) for Digital Twins. OABE-VPUDA empowers Data Owners (DOs) and Data Users (DUs) by enabling verifiable outsourced encryption, where a Public Verifier confirms Cloud Server (CS) computations, and verifiable outsourced de cryption, validated by DUs using an inspired tag mechanism. The scheme further incorporates dynamic attribute management via on-chain expiration tags for timely, fine-grained revocation, and allows DOs to securely and verifiably modify ciphertext access policies with CS assistance. A consortium blockchain underpins these functionalities, significantly enhancing system transparency, auditability, and overall trust in collaborative DT ecosystems. Formal security analysis rigorously demonstrates that the OABE-VPUDA scheme is secure against chosen-plaintext attacks, thereby ensuring robust data confidentiality, and its de sign ensures the verifiability of all critical outsourced operations within a provable security framework. Experimental results from a prototype implementation confirm the scheme's operational efficiency and practical applicability, highlighting its suitability for secure and agile data sharing in resource-aware digital twin applications.

Industrial Internet of Things (IIoT) enables highly automated and intelligent cross-domain communication. Due to varying computational capabilities and security requirements, cross-domain IIoT data sharing involves the design of security protocols using different cryptosystems. Attribute-based searchable encryption enables fine-grained access control and ciphertext retrieval, but existing schemes are primarily designed on a singular cryptosystem, lacking support for searches on heterogeneous ciphertext. Moreover, related schemes still suffer from technical challenges, such as the single point bottleneck, caused by a single attribute authority, issues with attribute updates, and forward secrecy attacks. In this article, we propose an attribute-based heterogeneous data privacy sharing (AB-HDPS) scheme for blockchain-assisted IIoT. Attribute-authorized users within a public key infrastructure cryptosystem can search ciphertext from data owners in a certificateless cryptosystem. The scheme utilizes multiple authorities to generate attribute keys, employs a glass-box traceable mechanism to prevent misuse of attribute keys, and implements subset-cover trees for attribute revocation. Specifically, leveraging the immutability of blockchain, the AB-HDPS scheme supports traceability and auditing of user access. Security analysis shows that the AB-HDPS scheme can resist internal keyword guessing and chosen-plaintext attacks, and it satisfies forward security. Comparative experimental simulations demonstrate that the AB-HDPS scheme with outsourced decryption has satisfactory computational performance, and the performance of the blockchain system within the scheme is commendable.

To achieve fine-grained access control and address the data silos challenge in data sharing, the integration of blockchain with attribute-based encryption emerges as a promising solution. Nowadays, the growing interconnectedness among diverse blockchain applications has spurred the need for efficient cross-chain data sharing. However, existing single-authority attribute-based data sharing schemes are not suitable for such cross-chain scenarios involving multiple attribute authorities. Moreover, the frequent requirement for data owners to process cross-chain data requests significantly hampers practicality. In this context, we introduce a novel multi-authority attribute-based proxy re-encryption scheme that enables ciphertext policy updating and supports secure and efficient cross-chain data sharing. By introducing a proxy, the data owner is empowered to delegate access without leaking any valid information and flexibly sells data across blockchains through cross-chain access policies. Besides, our scheme leverages the relay chain to foster a decentralized and trustworthy ecosystem. The adoption of smart contracts automates the cross-chain data sharing process and ensures equitable distribution of benefits among participants. Additionally, our scheme integrates hybrid encryption with the decentralized data hosting platform, substantially mitigating the on-chain storage burden. Security analysis affirms that our scheme is semantically secure and resistant to collusion attack. Performance analysis and simulation experiments demonstrate the excellent efficiency and practicality of our scheme when conducting cross-chain data sharing.

Blockchain, as an emerging technology, is constantly evolving due to its remarkable advantages but is also subject to its unalterability, which leads to the misuse of blockchain storage and causes adverse effects. Hence, the redactable blockchain was proposed, which can alleviate the above issues in a controlled manner. However, a situation exists in which the modifiers specified by customized identities or attributes in the existing schemes may be malicious, which can easily lead to malicious modification events. Evaluating, filtering, and limiting malicious modifiers in advance may be a feasible solution to the situation. Hence, we propose an efficient dynamic trust-based redactable blockchain supporting update and traceability, which offers full-process security with pre-modification pre-evaluation, modification privilege restrictions, and post-modification traceability. Firstly, we consider the user’s various behaviors and multiple factors and customize a dynamic trust evaluation model for redactable blockchain to comprehensively evaluate the reliability of the user. Then, we combine the user’s trust worthiness, dynamic proactive secret sharing($\mathcal {DPSS}$), chameleon hash($\mathcal {CH}$), and digital signature ($\mathcal {DS}$) to design a dynamic trust-based chameleon hash supporting update and traceability, called$\mathcal {DTCH}$, to realize full-process security, and prove its security. Thirdly, we construct the$\mathcal {DTCH}$-based redactable blockchain supporting update and traceability, demonstrate its security and further apply it to consortium blockchain. Finally, we evaluate the performance of the constructed model and scheme, and the evaluation results illuminate that they are not only effective but also possess better performance.