不可靠网络环境下的数字时间戳服务研究

数字时间戳(DTS)技术被广泛用于数字签名、电子商务及各种软硬件产品的专利和产权保护。在一些网络状况差、网速变化大、时断时续的不可靠网络中，缺乏必要的技术手段来保证时间戳服务的正常、有效运行。根据不可靠网络的特点，设计了一个不实时依赖时间戳服务中心(TSA)的时间服务模型，每次进行时间戳服务时不再需要与远程TSA进行通信，而是通过本地可信平台来进行时间戳服务。还提出一种不可靠网络环境下基于可信平台模块(TPM)的数字时间戳服务协议，并对协议进行了安全性分析。结果表明，协议是安全的，协议产生的时间误差是可控的，对不可靠网络有很好的适应性。

Research of digital time-stamping service in unreliable networks

The technology of Digital Time-Stamping (DTS) is widely used in digital signature, electronic commerce and patents and property right protection of various software and hardware. For some unreliable networks, of which the network situation is poor, the net speed changes greatly and the net links are usually intermittent, there is no necessary technological means to guarantee the normal and effective operation of DTS service. According to the characteristics of the unreliable networks, a new time-stamping scheme was proposed. In the scheme, it did not need to communicate with Time Stamp Authority (TSA) each time when a time-stamping service was required. The local trusted platform would offer the time-stamping service itself. A new DTS service protocol based on Trusted Platform Module (TPM) was also proposed under the circumstances of unreliable networks. The results of the security analysis of the protocol show that the protocol is secure and the time error in the protocol can be kept under control. The adaptability of the protocol for the unreliable network is excellent.