Cryptanalysis to Ming et al.'s Revocable Multi-Authority Attribute-Based Encryption

To achieve data sharing model in clouds under modern technology, several attribute-based encryption schemes have been proposed in many different ways. attribute-based encryption (ABE) is a one-to-many, fine-grained access control mechanism. Based on elliptic curve cryptography, we can reduce the computation overhead. However, most of these ABE schemes over elliptic curves are insecure or lacking of security proofs. In this manuscript, we review on the revocable multi-authority attribute-based encryption proposed by Ming et al.'s in 2021 and give the cryptanalysis on their scheme. More specifically, we demonstrate an attacking method to their scheme. Our attack allows any two users owning a same attribute colluding with each other, to generate private key of any chosen attribute set.