## Cryptology ePrint Archive: Report 2020/749

Insecurity of the Public Key Encryption with Filtered Equality Test Proposed by Huang et al.

Hyung Tae Lee and San Ling and Jae Hong Seo and Huaxiong Wang

Abstract: Recently, Huang et al. proposed a concept of public key encryption with filtered equality test (PKE-FET) that allows a tester who has a warrant for the selected message set to check equality of messages in ciphertexts that belong to that set (Journal of Computer and System Sciences, 2017). They also presented an instantiation of the PKE-FET that was asserted to achieve the indistinguishability against adaptive chosen ciphertext attacks (IND-CCA2) in the standard model. In this note, we show that Huang et al.’s instantiation does not achieve the IND-CCA2 security by presenting a simple adaptive chosen ciphertext attack.

Category / Keywords: public-key cryptography / Computation over ciphertext, filtered equality test, adaptive chosen ciphertext attacks