Integrating Private and Accountable Threshold Signature Into Ciphertext-Policy Attribute-Based Encryption Supporting Collaboration Decryption

Cloud services are becoming increasingly popular in social life. Collaboration in the cloud is critical for teams in different locations and organizations. However, the current collaborative decryption scheme requires all members to be online in order to decrypt, which causes offline members to affect the progress of the project. In this paper, we propose a more flexible and reliable collaborative decryption solution for team collaboration scenarios in cloud services. Our solution, based on the Threshold Accountable Private Signature (TAPS) framework, offers higher security, practicality, and lower overhead. Unlike the existing scheme, our approach allows for decryption when the number of online members reaches a certain threshold. Additionally, our framework can track individual members instead of all members, ensuring continuity of collaboration. To demonstrate the practicality and efficiency of our framework, we implement and verify its usefulness through experiments using the Rust programming language.