Decentralized Policy-Hidden Fine-Grained Redaction in Blockchain-Based IoT Systems

Abstract

Currently, decentralized redactable blockchains have been widely applied in IoT systems for secure and controllable data management. Unfortunately, existing works ignore policy privacy (i.e., the content of users’ redaction policies), causing severe privacy leakage threats to users since users’ policies usually contain large amounts of private information (e.g., health conditions and geographical locations) and limiting the applications in IoT systems. To bridge this research gap, we propose PFRB, a policy-hidden fine-grained redactable blockchain in decentralized blockchain-based IoT systems. PFRB follows the decentralized settings and fine-grained chameleon hash-based redaction in existing redactable blockchains. In addition, PFRB hides users’ policies during policy matching such that apart from successful policy matching, users’ policy contents cannot be inferred and valid redactions cannot be executed. Some main technical challenges include determining how to hide policy contents and support policy matching. Inspired by Newton’s interpolation formula-based secret sharing, PFRB converts policy contents into polynomial parameters and utilizes multi-authority attribute-based encryption to further hide these parameters. Theoretical analysis proves the correctness and security against the chosen-plaintext attack. Extensive experiments on the FISCO blockchain platform and IoT devices show that PFRB achieves competitive efficiency over current redactable blockchains.

Evaluation of Blockchain Networks’ Scalability Limitations in Low-Powered Internet of Things (IoT) Sensor Networks

“…According to Hongchen Guo et al, decentralized blockchains have been widely used for IoT systems to secure data management [22]. As the authors emphasized, most existing works have ignored user privacy, which can cause severe privacy issues.…”

“…As the authors emphasized, most existing works have ignored user privacy, which can cause severe privacy issues. As per the authors, privacy concerns may limit the wide use of IoT systems in any domain [22]. The authors have proposed a Policy-hidden Fine-grained Redactable Blockchain (PFRB) solution to cover the research gap [22].…”

“…As per the authors, privacy concerns may limit the wide use of IoT systems in any domain [22]. The authors have proposed a Policy-hidden Fine-grained Redactable Blockchain (PFRB) solution to cover the research gap [22]. This solution allows users to match the existing blockchain policies and policy contents.…”

“…As the authors have highlighted, PFRB is successful against plaintext attacks. The authors have used the Policy-based Chameleon Hash technique (PCH) to design the PFRB [22]. Also, the authors have emphasized the practical use case scenario of PFRB in smart healthcare systems.…”

PIRB: Privacy-Preserving Identity-Based Redactable Blockchains with Accountability

“…Regrettably, none of the above schemes preserves policy privacy. Guo et al [38] proposed a decentralized policy-hidden fine-grained redactable blockchain. Moreover, in cases involving bilateral access control scenarios, none of these schemes offer viable solutions.…”