Hitachi, Ltd.

Tadaoki Uesugi

Takahiro Fujishiro

Hisanori Mishima

Takeshi Akutsu

When a document creation unitis started, it calculates a hash value of each software piece therein and stores the hash value in a hash value holderand a measurement log document holder. The document creation unitaccesses a time distribution unit plural times to receive time information therefrom, and records the time information in a log document and a measurement log document. The document creation unittransmits the log document, the measurement log document, and digital signature-embedded hash value information (measurement auxiliary document) in a tamper-resistant deviceto a document reception device. The document reception device verifies matching of the hash values or digital signature in the document group, confirms software operating environments in the document creation unitfrom the hash values, and determines whether the time information is correctly managed within the unit

Growing community of inventors

Sagamihara, Japan

Tadaoki Uesugi