Autonomous Path Identity-Based Broadcast Proxy Re-Encryption for Data Sharing in Clouds

Cloud computing with massive storage and computing capabilities has become widespread in actual applications. It is critical to ensure secure data sharing in cloud-based applications. Currently, numerous identity-based broadcast proxy re-encryption (IB-BPRE) schemes have been proposed to resolve the privacy issue. However, the existing IB-BPRE schemes cannot reach the transformation of the decryption right for outsourced encrypted data between the broadcast receiver sets (data user sets) delegated by the data owner (Alice) because it is difficult for the IB-BPRE to hold the character of multi-hop. Consequently, a new cryptographic primitive called autonomous path identity-based broadcast proxy re-encryption (APIB-BPRE) is presented to address the above issue. In an APIB-BPRE scheme, the delegator establishes an autonomous path involving preferred multiple broadcast receiver sets and the proxy can convert the decryption right for the broadcast receiver set into the decryption right for the next broadcast receiver set by the re-encryption key from the delegator. This solution is convenient and flexible for cloud users and utilizes the benefits of cloud computing. The evaluation and comparison indicate that our APIB-BPRE system is effective and practical.