强安全模型下TLS1.3协议的形式化分析与优化

Formal Analysis and Optimization of TLS1.3 Protocol in Strong Security Model

TLS协议在TCP/IP体系中的传输层和应用层之间工作,通过提供机密性、完整性、必选的服务器认证以及可选的客户端认证等一系列安全服务,有效保护了传输层的安全.TLS1.3协议为了降低网络延迟,增加了对0-RTT数据的支持,通过客户端缓存服务器的长期公钥,在第1条消息中,直接利用该长期公钥生成一个会话密钥发送部分应用层数据.针对3种0-RTT模式,使用Scyther工具对其进行了形式化分析,得出了在CK安全模型下,0-RTT数据的两种攻击,并基于其中的1-RTT semi-static模式提出了一种优化协议.通过安全性证明和形式化分析,证明了该优化协议在CK安全模型下能够抵抗针对0-RTT数据的KCI攻击和重放攻击.

TLS protocol works between the transport layer and application layer in TCP/IP system.The safety of transport layer is effectively protected by providing a series of security services such as confidentiality,integrity,authentication server required,as well as optional client authentication.In order to reduce network latency,TLS1.3 protocol adds the support for 0-RTT data,through caching long-term public key of server by client,and the long-term public key is directly used to generate a session key to send part of application layer data in the first message.For three kinds of 0-RTT mode,this study uses Scyther tools for formal analysis to obtain two attack paths of the 0-RTT data in CK security model,and an optimized protocol is proposed based on the 1-RTT semi-static mode.Through security proof and formal analysis,it is proved that the protocol is resistant to KCI attacks and replay attack against 0-RTT data in CK security model.