关键词: 无证书签名, 公钥替换攻击, 恶意密钥生成中心（KGC）攻击, 双线性对

Abstract: This paper analyzes a certificateless signature scheme, and points out the scheme can’t resist to the public key replacement attack and the malicious KGC（Key Generation Center） attack. The attacker can forge the signature for any message by substituting the public key of the signer. The malicious KGC can get the private key. The analysis shows that the scheme can not satisfy the safety requirements of the certificateless signature. Meanwhile the improvement measure is proposed to resist these attacks.

Key words: certificateless signature, public key replacement attack, malicious Key Generation Center（KGC） attack, bilinear pairing