A Pairing-Free Identity-Based Broadcast Proxy Re-Encryption Scheme for the Cloud

In cloud computing environments, the data owner typically chooses to encrypt his data before storing it on cloud servers. When multiple users request access to the data owner’s information, the cloud server can utilize broadcast proxy re-encryption technology to convert the data owner’s original ciphertext into new ciphertexts for these users to decrypt. Most existing broadcast proxy re-encryption schemes rely on bilinear pairings and hash-to-point operations, which reduce computational efficiency and are impractical for resource-constrained proxy servers. To address this issue, we propose an identity-based broadcast proxy re-encryption scheme that eliminates these complex operations, thereby reducing computational complexity and implementation costs. This scheme can resist chosen-ciphertext attacks and collusion attacks in the random oracle model(ROM). Analysis results show that the proposed scheme maintains security while achieving high computational efficiency.