Cryptanalysis on Two Pairing-Free Ciphertext-Policy Attribute-Based Encryption Schemes
Yi‐Fan Tseng, Jheng-Jia Huang · 2020
Ciphertext-policy attribute-based encryption (CPABE) provides fine-grained access control, which is suitable for the modern data sharing model. Lots of CP-ABE schemes constructed over different mathematical structures, such as pairing groups, lattices, etc. Recently, Ding et al. and Wang et al. independently proposed two pairing-free CP-ABE schemes, using only elliptic curve cryptography. However, we found that their schemes are insecure. In this manuscript, we review their schemes and give the corresponding cryptanalysis. We show that, their schemes are vulnerable against collusion attacks.