[論文レビュー] MedExChain: Enabling Secure and Efffcient PHR Sharing Across Heterogeneous Blockchains

Yongyang Lv, Xiaohong Li+4 more|arXiv (Cornell University)|Feb 12, 2026

Blockchain Technology Applications and Security被引用数 0

ひとこと要約

MedExChainは、Cryptographic Reverse Firewallを用いた強化プロキシ再暗号化を備えた異種ブロックチェーン間でのPHR共有スキームを提供し、データを保護しIoMTのオーバーヘッドを削減します。

ABSTRACT

With the proliferation of intelligent healthcare systems, patients' Personal Health Records (PHR) generated by the Internet of Medical Things (IoMT) in real-time play a vital role in disease diagnosis. The integration of emerging blockchain technologies signiffcantly enhanced the data security inside intelligent medical systems. However, data sharing across different systems based on varied blockchain architectures is still constrained by the unsolved performance and security challenges. This paper constructs a cross-chain data sharing scheme, termed MedExChain, which aims to securely share PHR across heterogeneous blockchain systems. The MedExChain scheme ensures that PHR can be shared across chains even under the performance limitations of IoMT devices. Additionally, the scheme incorporates Cryptographic Reverse Firewall (CRF) and a blockchain audit mechanism to defend against both internal and external security threats. The robustness of our scheme is validated through BAN logic, Scyther tool, Chosen Plaintext Attack (CPA) and Algorithm Substitution Attack (ASA) security analysis veriffcation. Extensive evaluations demonstrate that MedExChain signiffcantly minimizes computation and communication overhead, making it suitable for IoMT devices and fostering the efffcient circulation of PHR across diverse blockchain systems.

研究の動機と目的

• Motivate secure real-time PHR sharing from IoMT devices across heterogeneous blockchains.
• Enable cross-chain data sharing while considering IoMT device storage and computation limits.
• Provide robust security proofs against internal and external threats including ASA.
• Minimize computation and communication overhead to suit IoMT environments.

提案手法

• Proposes MedExChain, a cross-chain PHR sharing scheme built on an improved proxy re-encryption (PRE) algorithm.
• Incorporates Cryptographic Reverse Firewall (CRF) to defend against backdoor attacks.
• Stores PHRs encrypted in IPFS and uses smart contracts for cross-chain workflows.
• Validates security with BAN logic, Scyther tool, CPA and ASA analyses.
• Supports data owners encrypting data once and data users decrypting via re-encrypted ciphertext across chains.
• Evaluates computational and communication overhead against multiple reference schemes.

実験結果

リサーチクエスチョン

• RQ1 How can PHRs be securely shared across heterogeneous blockchains with differing cryptographic systems?
• RQ2 Can the scheme minimize IoMT overhead while maintaining confidentiality and integrity?
• RQ3 Does the integrated CRF provide resilient defense against algorithm substitution and exfiltration threats across chains?
• RQ4 What are the security guarantees under BAN logic, Scyther, CPA and ASA analyses for MedExChain?

主な発見

• MedExChain enables cross-chain PHR sharing with real-time IoMT data encrypted on IPFS and re-encrypted for the target chain.
• The scheme demonstrates enhanced security by integrating Cryptographic Reverse Firewall and formal security analyses (BAN logic, Scyther, CPA, ASA).
• Experimental evaluation shows lower communication overhead per data unit in ReKeyGen and ReEnc stages compared with five references.
• System throughput and latency measurements indicate feasibility for cross-chain PHR circulation across heterogeneous blockchains.