Abstract: A local timestamp issuing apparatus according to the present invention includes: a timestamp issuing unit configured to, in response to a request for a timestamp for electronic data by a predetermined information processing apparatus installed in the same local environment, issue a timestamp token for the electronic data; a ledger timestamp requesting unit configured to, at a preset timing, connect to a specific timestamp issuing apparatus installed on the Internet, and request a timestamp for ledger data including the timestamp token issued for the electronic data from the specific timestamp issuing apparatus; and a ledger timestamp acquiring unit configured to acquire the timestamp token issued for the ledger data from the specific timestamp issuing apparatus.