【摘要】 通过对电子商务中不可否认公平交换协议的运行流程进行了研究,论证了基于第三方的不可否认公平交换协议至少需要运行4步骤,进而指出现有一个协议实质上是需要运行4步骤的,而不仅仅是运行3步骤。依据安全协议与密码系统分开设计的原则,对比分析已有可转换认证加密方案,提出了一个可转换认证加密方案的系统模型。并基于该系统模型,设计了基于半可信第三方的不可否认的安全邮件协议。通过形式化方法分析表明,该协议具备邮件发送方和接收方均不可否认的特点。更多还原

【Abstract】 On deep research on the workflow of non-repudiation and fair-exchange protocols in electronic commerce,it is proved that these protocols with trusted third party need to run in four steps at least. The analysis of an existing protocol shows that it needs to run in four steps,rather than just run in three steps it claims. On the principle that security protocol and cryptography system should be designed separately,a common model of convertible authenticated encryption schemes is proposed by analyzing some existing convertible authenticated encryption schemes. By using this model,a secure email protocol with semi-trusted third party is designed. Result shows that this protocol has non-repudiation features of both sender and receiver by formal analysis.更多还原