Distributed Attribute-Based Threshold Proxy Re-Encryption with Public Verification and User Revocation

Le résumé fourni par la source

For ciphertext data sharing in cloud environments, attribute-based encryption provides fine-grained access control, but there are contradictions between implementation and security in cross-user authorization, proxy re-encryption trustworthiness, and dynamic user revocation. This paper proposes a distributed attribute-based threshold proxy re-encryption scheme DAB-TPRE-PV-UR, which introduces a two-phase re-encryption mechanism with multi-proxy node collaboration, distributing re-encryption capability in a threshold manner to multiple proxy servers and the central cloud server to reduce risks of single proxy compromise or collusion. Furthermore, a public verification procedure executed by a trusted authority is designed: when a data requester doubts the correctness and integrity of re-encrypted results, it can trigger third-party verification and publicize the conclusion, realizing auditable dispute resolution. For dynamic authorization scenarios, an accurate revocation method bound to the access structure is proposed, achieving persistent invalidation of revoked users by updating re-encryption keys and their corresponding access matrices. In terms of security, the scheme is proven to satisfy IND-sAS-CPA security under selective access structures in the standard model. Performance comparisons with similar ABPRE schemes show that the scheme maintains acceptable computational cost while providing threshold and public verification capabilities.

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