基于认证公钥的抗合谋攻击加密方案

An Encryption Scheme with Collusion Attack Security Based on Certified Public-Key

针对Gentry基于认证的公钥加密方案不能抵抗拒绝服务攻击和合谋攻击的问题,改进并优化了基于认证公钥加密方案,给出了该方案的安全模型、具体算法和标准模型下安全分析.在该方案中,用户利用第三方对其公钥和/或身份的认证对自选公钥进行签名;在加密消息前加密者将验证接收方对自选公钥的签名;公钥发布者如果没有合法授权将不能给出正确的签名,在保留Gentry方案优势的条件下能拒绝服务攻击和抵抗合谋攻击.

Based on Gen sist the DoS attack and the try＇s certificate-based public-key encryption （CBE） scheme, which can not recollusion attack, we propose an improved CBE scheme and give the security model, concrete algorithm and security analysis in the standard model. In the improved scheme, the user signs his own public key by a certification that is signed by a third party on the user＇s public key and/or his identity. Before the encryption operation, message sender should verify the signature on the receiver＇s own public key. Without the legal authority, the receiver would not give the right signature. So the improved scheme can resist the DoS attacks and the collusion attacks.