System, method and program for managing information

17) A program for causing an information processor to function as a system for recording signature data indicating that information existed at a particular time, in association with the information;

• the program causing the information processor to function as:
• a first data acquisition section for acquiring first data generated based on the information to certify the identity of the information;
• a second data generation section for observing a target object changing with time elapse from outside the system and generating second data based on observation data obtained as a result of the observation, in response to an instruction received from a first user;
• a signature data generation section for generating signature data indicating that the information existed at the time when the target object was observed, based on combination of the first data and the second data;
• and
• an information recording section for recording the signature data in association with the information.

18) A method to be applied to a system provided with an information management apparatus for adding signature data to information and a determination apparatus for determining the validity of the signature data;

• the method comprising, in the information management apparatus, the steps of:
• acquiring first data generated based on the information to certify the identity of the information;
• observing a target object changing with time elapse from outside the information management apparatus and generating second data based on observation data obtained as a result of the observation, in response to an instruction received from a first user;
• generating signature data indicating that the information existed at the time when the target object was observed, based on combination of the first data and the second data;
• and
• recording the signature data in association with the information;
• and
• the method comprising, in the determination apparatus, the steps of:
• sequentially observing the target object as time elapses and recording observation data obtained by the observation in association with the observation time;
• acquiring the information and the signature data recorded in the information management apparatus from the information management apparatus, in response to an instruction from a second user to the effect that the time when the information existed should be certified;
• and
• retrieving observation data corresponding to the time to be certified from the observation data obtained by sequential observation and determining whether or not the information existed at the time based on the retrieved observation data, the acquired information and signature data.