Comment on “Circuit Ciphertext-Policy Attribute-Based Hybrid Encryption With Verifiable Delegation in Cloud Computing”
Zhengjun Cao, Olivier Markowitch · IEEE Transactions on Parallel and Distributed Systems · 2020
The scheme [1] is flawed because: (1) its circuit access structure is confusingly described; (2) the cloud server cannot complete the related computations; (3) some users can conspire to generate new decryption keys, without the help of the key generation authority.