三接收方公钥密码系统

Triple receiver public key encryption cryptosystem

提出一种三接收方公钥加密方案,该方案中发送方对消息进行加密,而三接收方均能够使用各自的私钥对消息进行解密。基于双线性映射,构造出两个安全性不同的三接收方公钥加密方案。形式化证明如果间隙双线性Diffie-Hellman问题和计算性Diffie-Hellman问题是困难的,则所提的两个方案分别具有选择明文攻击安全和适应性选择密文攻击安全。所提方案仅增加了一项指数运算和一项哈希运算,就实现了3个独立的接收方,因此该方案效率较高。分析表明,该方案能够提高TLS协议的安全性并应用于分级监管公钥密码系统。

A triple receiver public key cryptosystem was proposed.In the cryptosystem,a sender encrypted a message and sent to three receivers,while the three receivers were able to decrypt the message with their own private keys.Based on bilinear map,two triple receiver public key encryption schemes with different security were constructed.If the gap bilinear Diffie-Hellman(GBDH)problem and the computational Diffie-Hellman(CDH)problem were proved formally to be intractable,then the two schemes proposed were semantically secure against chosen-plaintext attacks and against adaptive chosen ciphertext attacks respectively.The proposed scheme only added an exponential operation and a hash operation,and constructed three independent receivers which had a high efficiency.Analyses show that proposed scheme can improve the security of TLS protocol and apply to hierarchical public key cryptosystems.