Adaptively secure multi-authority attribute-based broadcast encryption in fog computing

Fog computing is considered an important development in cloud computing, with shorter response times, less data transfer load and a more secure distributed service architecture that can be accessed by a wide range of end devices. As with cloud computing, it also faces the challenge of how to securely distribute sensitive data. Ciphertext-Policy Attribute-based Broadcast Encryption (CP-ABBE) can protect sensitive data and provide fine-grained access control with user revocation. However, existing CP-ABBE schemes suffer many limitations when implemented in a fog computing environment: a single authority performs poorly in handling requests or data from many IoT devices, leading to system delays or limited functionality; expensive decryption costs make the computation and storage overheads unfriendly to devices with limited resources; these schemes are only proven selectively secure, meaning that security was proven in a weaker model. In this paper, using threshold secret sharing and decryption delegation, we propose an adaptively secure attribute-based multi-authority broadcast encryption (MA-ABBE) scheme that breaks through these limitations. The comparison and analysis results show that our scheme is practical and achieves adaptive security, enables user-side fast decryption and low storage overhead, and provides a secure and efficient option for protecting sensitive data in fog computing environments.