Improved Public Key Encryption Scheme Secure Against Adaptive Chosen-Ciphertext Attacks

Abstract

It is an important research topic in public key cryptography to design public key encryption schemes secure against adaptive chosen-ciphertext attacks in the standard model.Kang et al.proposed an efficient public key encryption scheme,and claimed that their scheme satisfies the security of indistinguishability against adaptive chosen-ciphertext attacks(IND-CCA2).However,by giving an adaptive chosen-ciphertext attack,we indicate that their scheme is not IND-CCA2 secure.We further improved Kang et al.' s scheme to obtain a new public key encryption scheme,and prove its IND-CCA2 security in the standard model.