摘要
This paper formally discusses the security problem caused by the ciphertext verification, presenting a new security notion named IND-CVA （indistinguishability under ciphertext verification attacks） to characterize the privacy of encryption schemes in this situation. Allowing the adversary to access to both encryption oracle and ciphertext verification oracle, the new notion IND-CVA is slightly stronger than IND-CPA （indistinguishability under chosen-plaintext attacks） but much weaker than IND-CCA （indistin- guishability under chosen-ciphertext attacks）, and can be satisfied by most of the popular symmetric encryption schemes such as OTP （one-time-pad）, CBC （cipher block chaining） and CTR （counter）. An MAC （message authentication scheme） is usually combined with an encryption to guarantee secure communication （e.g. SSH, SSL and IPSec）. However, with the notion of IND-CVA, this paper shows that a secure MAC can spoil the privacy in some cases.
This paper formally discusses the security problem caused by the ciphertext verification, presenting a new security notion named IND-CVA （indistinguishability under ciphertext verification attacks） to characterize the privacy of encryption schemes in this situation. Allowing the adversary to access to both encryption oracle and ciphertext verification oracle, the new notion IND-CVA is slightly stronger than IND-CPA （indistinguishability under chosen-plaintext attacks） but much weaker than IND-CCA （indistin- guishability under chosen-ciphertext attacks）, and can be satisfied by most of the popular symmetric encryption schemes such as OTP （one-time-pad）, CBC （cipher block chaining） and CTR （counter）. An MAC （message authentication scheme） is usually combined with an encryption to guarantee secure communication （e.g. SSH, SSL and IPSec）. However, with the notion of IND-CVA, this paper shows that a secure MAC can spoil the privacy in some cases.
基金
the National Basic Research Program of China (Grant No. G2002cb312205)
