Justification authenticating system, personal certificate issuing system, and personal certificate

A personal certificate issuing system comprising:

• an identifier generating unit operable to generate an identifier unique to a personal certificate;
• a watermark information generating unit operable to generate digital watermark information corresponding to said identifier;
• a database for storing said identifier of said personal certificate and said digital watermark information relative to said identifier in relation to each other;
• a watermark information registering unit operable to store said identifier generated by said identifier generating unit and said digital watermark information generated by said watermark information generating unit in said database;
• an image input unit operable to input a raw authentic image;
• a watermark-embedded image forming unit operable to form a watermark-embedded authentic image in which said digital watermark is embedded on said authentic image input by said image input unit;
• and
• a personal certificate that readably carries said authentic image generated by said watermark-embedded image forming unit and said identifier generated by said identifier generating unit;
• wherein said digital watermark information stored in said database and embedded in said authentic image of said personal certificate is update according to predetermined timing, and said predetermined timing includes each time said system correctly justifies an authentic image.