A Symmetric Authenticated Proxy Re-Encryption Scheme With Provable Security

In crypto 2013, Dan et al. proposed a symmetric proxy re-encryption scheme based on key homomorphic PRF. It can be used to ensure the data privacy in cloud storage systems. However, it only focuses on preventing a honest-but-curious proxy from learning anything about the encrypted data. Although it can be made to provide integrity without disrupting the key homomorphism property by using MAC then encrypt with counter-mode, it's not a symmetric authenticated proxy re-encryption scheme because only the data owner can verify the integrity of some encrypted data. In this paper, we propose a symmetric authenticated proxy re-encryption scheme which can prevent a malicious proxy from tampering users' data. It can update the authentication tag as well as the ciphertext so that any intended user can verify the integrity of the encrypted data.