无证书密文等值测试签密方案

Certificateless Signcryption with Equality Test

在云计算应用中,确保消息的机密性和不可伪造性,同时判断不同密文对应明文的等价性显得至关重要。具有密文等值测试功能的签密方案可以实现此类安全目标。该文基于无证书公钥密码环境,设计了一个具有密文等值测试功能的无证书签密方案(CLSCET)。首先,提出了无证书密文等值测试签密方案的框架和安全模型,定义了两类具有不同攻击能力的敌手和3类安全目标。然后构造了具体的无证书密文等值测试签密方案,并分析了方案的正确性。最后,基于随机预言模型,证明该文方案满足选择密文攻击下的单向性(OW-CCA)、选择密文攻击下的不可区分性(IND-CCA2)和选择消息攻击下的不可伪造性(EUF-CMA)安全。与现有近似方案相比,该文方案满足IND-CCA2的机密性、EUF-CMA的不可伪造性和OW-CCA的密文单向性。

In cloud computing applications, it is very important to ensure the confidentiality and unforgeability of messages, while judging the equivalence of different ciphertexts to plaintexts. The signcryption scheme with equality test can achieve the above security goals. Based on the certificateless public key cryptography environment, a Certificateless SignCryption scheme with Equality Test(CLSCET) is designed. Firstly, the framework and security model of the certificateless signcryption with equality test scheme are proposed,moreover two types of adversaries with different attack capabilities and three types of security targets are defined. Secondly, a specific certificateless signcryption with equality test scheme is constructed, and the correctness of the scheme is analyzed. Finally, based on the random oracle model, it is proved that the scheme satisfies the security properties of One-Way against Chosen Ciphertext Attack(OW-CCA), INDistinguishability against adaptive Chosen Ciphertext Attack(IND-CCA2) and Existential UnForgeability against adaptive Chosen Message Attack(EUF-CMA). Compared with the existing approximate schemes, the scheme satisfies the confidentiality of IND-CCA2, the unforgeability of EUF-CMA and the one-way ciphertext of OW-CCA.