An efficient outsourcing attribute-based encryption scheme in 5G mobile network environments

Attribute-based encryption (ABE) provides a fine-grained access control mode for multiuser network environments. The popularity of 5th generation (5G) mobile network applications has greatly increased the data transmission rate, but mobile terminal devices with limited resources in the network have difficulty with the high computational overhead of ABE in wireless communication. In response to this problem, this paper proposes a hybrid encryption online/offline ciphertext policy attribute-based encryption (CP-ABE) scheme for 5G. In the scheme, the data owner uses symmetric encryption technology to perform data encapsulation on plaintext and outsources the encapsulated plaintext to the cloud user assistant (CUA) for offline calculation. Key encapsulation is performed on a symmetric key to form the final ciphertext, and it is uploaded to the cloud server. After the data user obtains the ciphertext, it is handed over to the CUA for offline decryption calculation. If the access structure is satisfied, the encapsulated ciphertext can be obtained, and then the symmetric key is used to decrypt the ciphertext. In the scheme, the correctness of the symmetric key can be verified to prevent malicious tampering in the process of transmission. It is indicated that the scheme is secure after being tested with the decisional q-Parallel Bilinear Diffie-Hellman Exponent (BDHE). Numerical analysis shows that the scheme has decreased computational overhead and can achieve fine-grained access control of user decryption rights.