Identity-Based Threshold Broadcast Proxy Re-encryption Plus Scheme

In the significant data era, cloud data sharing provides a malleable and efficient manner to store, access, and share data. However, as users’ demand for information access increases. Large volumes of data are forwarded between the clouds. Among the issues waiting to be addressed are secure forwarding, privacy protection, and data access control. Proxy Re-Encryption (PRE) is an encryption technique based on the secure transformation of ciphertexts in scenarios such as cloud data sharing. PRE is an effective approach for solving data exchange security problems. In PRE, besides sharing data users, semi-trusted agents also play an important role in data sharing. Therefore, essential measures should be taken in the area of re-encryption to enlarge the security of data sharing. In response to this issue, An identity-based threshold broadcast proxy re-encryption scheme (TIB-PRE+) is proposed. TIB-PRE+ makes use of the idea of thresholding, which weakens the threat posed by semi-trusted agents to the secure sharing of data by secretly sharing a portion of the re-encryption key with different subagents. It weakens the privileges of individual agents and reduces the threat of a single agent being attacked and bringing down the system. TIBPRE+ also takes into account the advantages and features of PRE+. Finally, all user identity information of the receiver set in the TIBPRE+ scheme is not explicitly shared with the receiver, which enhances privacy protection. TIB-PRE+ satisfies the security under the stochastic predictive machine model, and after comparing it with other related schemes, it can be seen that TIB-PRE+ has better security. TIB-PRE+ can be effectively used in healthcare data-sharing scenarios.