一个无证书签密方案的安全性分析

Cryptanalysis of a Certificateless Sgncryption Scheme

对周敏等人提出的无证书签密方案进行了安全性分析,指出该方案存在以下安全缺陷:方案不能抵抗不可区分性选择明文攻击;利用公钥替换攻击,敌手可以伪造用户对任意消息的签密;恶意KGC可以对任意消息伪造签密,也可以对任意签密文进行解密;对消息的加解密密钥不含随机因子,使得方案不具有前向安全性.

Cryptanalysis of the certificateless verifiable signcryption scheme proposed by Zhou Min et al shows that the scheme has the following security flaws： the scheme can’t resist indistinguishability under the chosen ciphertext attack;the adversary can forge a valid signcryption ciphertext for any message of any user under public key replacement attacks;the malicious KGC can forge the ciphertext for any message and can also decrypt any ciphertext;the scheme is not forward-secure because the encryption key does not contain a random number.