Timestamp refers to the total number of seconds from 00:00 on January 1, 1970 Greenwich Mean Time to the present. Simply put, a timestamp is a complete and verifiable representation of data that already exists at a specific point in time. Its proposal is mainly to provide users with an electronic evidence to prove the generation time of certain user data. In practical applications, it can be used in various aspects including e-commerce and financial activities, especially as an "undeniable" service to support public key infrastructure