A Blockchain-Integrated Privacy-Preserving CP-ABE Framework for Secure Multimodal Data Access Control in Dynamic Cloud-IoT Environments

Abstract

The scale of multimodal data generated by cloud computing systems, Internet of Things (IoT) devices, and autonomous intelligent systems is growing rapidly, which has compounded the need to have secure, decentralized and fine-grained access control mechanisms. The conventional access control models in most occasions have drawbacks in respect to the scalability aspect, privacy preservation and adaptability in dynamic environments. To overcome these issues, this paper suggests a new blockchain-enabled Ciphertext-Policy Attribute-Based Encryption (BC-CP-ABE) model of secure multimodal data access control in distributed cloud-IoT ecosystems. The suggested structure integrates CP-ABE, policy auditing based on blockchain, access validation with smart contracts and decryption outsourcing to guarantee privacyfocused authorization and effective access control. The mapped fuzzy and context-aware authorization rules that are semantically mapped are employed to map the multimodal attributes created out of structured and unstructured data sources into adaptive access policies. The blockchain offers a policy storage that cannot be changed, an open revocation mechanism, and auditing that is impervious, and out-of-source decryption is really important in reducing the computing load of end users and resource-limited IoT devices. Additionally, a zeroknowledge, proof-based verification system is also proposed to make sure that the attributes are leaked as little as possible when validating the policy and a post-quantum lattice-based cryptographic engine is implemented to enhance resistance to quantum attacks in the future. The experimental analysis shows that the suggested framework enhances the accuracy of policy verification, revocation, and scaling at a higher rate than traditional CP-ABE models and safeguards the privacy. Lower decryption latency, improved throughput and increased robustness are also found in the findings and thus the framework is highly applicable in real-world decentralized security systems in healthcare, smart cities and industrial internet- of-things systems.