A Verifiable CP-ABE Scheme with Policy Hiding and Dynamic Attribute Revocation for Secure Medical IoT System

The IoMT enhances traditional healthcare processes through real-time data, accuracy, accessibility, and security, driving digital transformation in the medical field. However, as a dynamic and collaborative network, IoMT presents challenges such as privacy risks, access policy exposure, data integrity issues, inefficient dynamic permission management, and computational inefficiencies. To address these issues, this paper proposes an efficient CP-ABE scheme with policy hiding and real-time ciphertext verification. Attributes are divided into names and values, with only attribute names included in the cloud-stored access policy, preventing full policy exposure. Additionally, leveraging flexible private key parameters and bilinear pairing properties, the scheme designs a ciphertext verification and attribute revocation algorithm for real-time correctness validation and secure attribute revocation. Finally, the scheme incorporates an outsourced decryption algorithm, enabling the final decryption to be completed with only a single exponentiation operation, thereby significantly improving the decryption efficiency for resource-constrained devices. Security analysis and performance analysis confirms its resistance to chosen-plaintext attacks and practicability.