Abstract: Because the existing key management schemes are not applicable, a new key management scheme is proposed for the special DTN environment in the content delivery system for remote area which consists of satellite and portable terminal hybrid network. In the scheme, the satellite network receiving server in the content delivery system issues the digital identity cards for users. A user can generate his public-private key pair by himself, then he binds it with the digital identity card to produce the blind digital identity card which can be used for authentication and public key acquisition. By adding the lifetime of the key in the authentication data, the key of a user can be periodically updated and the replay attack for the public key acquisition can be prevented. This paper analyses the security of the scheme and compares it with other schemes. The analysis shows that the scheme meets the security requirements, which is suitable for the special DTN of the satellite and portable terminal hybrid network content delivery system.

Key words: Delay Tolerant Network（DTN）, key management, security, authentication, satellite and portable terminal, hybrid network, content delivery

摘要： 边远地区内容分发系统由卫星及便携终端混合网络组成，针对其中的特殊DTN环境，以及现有密钥管理方案不适用的问题，提出了一种新的密钥管理方案。利用系统中卫星网络接收服务器为用户颁发数字身份证，用户产生密钥对并将其与数字身份证绑定产生盲数字身份证，从而进行身份验证及公钥获取。在验证数据中加入密钥生存期，实现了用户密钥定期更新并且可以防止对公钥获取进行的重放攻击。分析了该方案的安全性并与其他方案进行了对比，分析表明该方案达到了安全性需求并适用于卫星及便携终端混合网络内容分发的DTN。

关键词: 延迟容忍网络（DTN）, 密钥管理, 安全, 身份认证, 卫星及便携终端, 混合网络, 内容分发