Exfiltration-Resistant Proxy Re-Encryption for IoT Data Sharing in Unreliable Clouds

The sharing of Internet of Things (IoT) data plays an extensive role in our everyday lives. Exploring secure and efficient methods for data sharing is a prominent area of research. Proxy re-encryption (PRE) in the cloud provides a solution. However, traditional PRE schemes are vulnerable to algorithm substitution attacks (ASA). Moreover, in most PRE schemes, the proxy can know the relevant identity information of the data owner or the data recipient through the re-encryption key, and some current PRE schemes cannot guarantee strong resistance to collision. To address the limitations of traditional PRE schemes and offer a robust solution for secure and efficient data sharing in IoT application, we propose a reverse firewall for proxy re-encryption (PRE-RF) scheme, which is implemented by JPBC library. Security analysis shows that our PRE-RF scheme provides effective resistance to ASA, along with strong collision security, chosen plaintext attack security, and key-private security. Compared with similar state-of-the-art PRE schemes, our scheme reduces the length of the re-encryption keys and ciphertext, thereby reducing the storage cost of the system. Meanwhile, our scheme’s computational cost is lower, thereby improving the operational efficiency of the system. Furthermore, the amount of time devoted to the reverse firewall in our scheme decreases as security level increases. As a result, these advantages make it a secure and efficient choice for sharing IoT data in unreliable cloud environments.