Abstract: In order to improve the expressivity of the access structure in attribute-based encryption, and avoid the interference of irrelevant attributes in the access structure,  a ciphertext-policy attribute-based encryption (CP-ABE) scheme based on reduced ordered binary decision diagram (ROBDD) access structure is proposed. The ROBDD access structure in this scheme can effectively express the access policy with complex access logic and prevent the interference of irrelevant attributes, which improves the encryption speed. RSA attribute authentication mechanism is introduced to achieve attribute authentication in non-leaf nodes of ROBDD, which realizes anti-collusion attack and protection of user attribute set. The effective path eigenvalues and encryption parameters in ROBDD are used to create polynomials, and any effective path eigenvalue can get encryption parameters through polynomial calculation, which reduces the cost of ciphertext storage overhead. The scheme implements user revocation, user attribute revocation, and system attribute revocation. Performance analysis and experimental simulation show that the proposed scheme has higher encryption and decryption efficiency, and lower ciphertext storage overhead.

Key words: ciphertext-policy attribute-based encryption, reduced ordered binary decision diagram, polynomial, RSA attribute authentication