Offline time-stamping system: Its design and implementation

Some time-stamping services are on business for protection of a document. A user can get the time-stamp just by connecting a terminal to the internet. However, if the user cannot connect to the internet, the document cannot be protected. Without regard to the internet access, if the user can get the time-stamp anywhere, time-stamping can use in many other situations. This paper proposes an offline time-stamping scheme. The scheme generates the time-stamp in a user´s terminal using TPM. TPM is a security chip. In this scheme, TPM is used for preventing a terminal user from generating a time-stamp containing falsified time. This paper shows an example of a design and an implementation of an offline time-stamping system based on the scheme. The system is designed in the REST -over-HTTP style. By using HTTP, the development is simplified because it is not necessary to build an interface, API, or others for each system a developer need to build. The implemented system can issue a time-stamp about 1,140ms under the experimental environment.