Hitachi, Ltd.

Hisashi Toyoshima

Kazuo Takaragi

Hiroshi Yoshiura

Ryoichi Sasaki

Seiichi Susaki

Kunihiko Miyazaki

Takeshi Matsuki

Tsukasa Saito

Toshiaki Arai

Masato Arai

Tsutomu Matsumoto

Shinji Itoh

Mitsuru Iwamura

Satoe Okayasu

Nobuaki Ono

Masaki Miyadera

Takashi Kawahara

Chikako Tsuchiyama

Chikako Kurita

Kayoko Sakaguchi

Ryohei Shiotani

According to the present invention, techniques, including a method and system, for restoring and/or validating data and/or associated signature log entries are provided. One embodiment of the present invention provides a method for validating a restored message, having an entry generated in a signature log for a message, where the entry includes cryptographic information associated with the message. Next, when said message is lost, the restored message is generated responsive to a request; and the restored message is validated using the signature log. In another embodiment a method for validating a selected log entry by using a signature log having a plurality of recorded log entries is provided. The method includes: computing a cryptographic value for the selected log entry; and determining if the cryptographic value is part of another recorded log entry.

Method and system for recovering the validity of cryptographically signed digital data

A method of communication involving processing by instruction using one or a combination of information units, when a user instructs a terminal to display contents and procedure of a communication, or to totalize the contents of the communication, or when a manager terminal instructs a field of the communication to provide a function of the communication corresponding to an object or stage of the communication. Information units forming the contents of the communication include cards, and information units forming premising information of a communication and a basis of the communication include boards. An information unit comprises a board identifier and attribute information for specifying a function of a board, such as a relationship between the board and cards. To provide a communication function corresponding to an object and stage of the communication, a template conforms to the object and stage so a manager can select and utilize the template.

Method for communication

Techniques of improving the safety of an information processing system at low cost are provided, the information processing system having an OS provided with an access control function based upon discretionary access control for preventing illegal accesses to files. A method and apparatus for providing the information processing system with functions and areas usable only by a specific user different from a system administrator. The areas are provided with an access control function in order to prevent the access control function from being tampered.

Trusted computer system

A time stamp generating system has a time distribution server for generating time data depending on time and a user PC for holding time certification objective digital data. The time distribution server generates time data corresponding to a time point and distributes the time data. The user PC calculates time stamp generating data by using the time certification objective data as an input, acquires the time data generated by the time distribution server, and processes the time data on the basis of the time stamp generating data to obtain a time stamp.

Time stamp generating system

According to the present invention, techniques, including a method and system, for restoring and/or validating data and/or associated signature log entries are provided. One embodiment of the present invention provides a method for validating a restored message, having an entry generated in a signature log for a message, where the entry includes cryptographic information associated with the message; Next, when said message is lost, the restored message is generated responsive to a request; and the restored message is validated using the signature log. In another embodiment a method for validating a selected log entry by using a signature log having a plurality of recorded log entries is provided. The method includes: computing a cryptographic value for the selected log entry; and determining if the cryptographic value is part of another recorded log entry.

A communication system includes a community management server used by a communication manager and a participant's terminal used by a community participant participating in communication. The community management server manages multimedia data that has data about the community participant embedded therein, an element symbolizing the community participant, a data content display control part and a participant personal identification authentication part. The participant's terminal includes generation part for generating card-like information as a communication unit. When a plurality of community participants executes communication by using the cards to which the multimedia data are put, they can execute information display of personal information of the community participants, authentication of personal identification, and retrieval/edition of a speech content by using information embedded in the multimedia data.

Method of information display and communication system using the method

This invention provides a method for identifying a purchaser who purchased content from which an illegal copy was produced. A provider system encrypts purchased by the purchaser using a public key of a purchaser system and sends the encrypted content to the purchaser system. The purchaser system creates a digital signature of the content with the use of a private key of its own and embeds the created digital signature into the received content. When an illegal copy is found, the provider system verifies the digital signature, embedded in the illegal copy as a digital watermark, to identify the purchaser who purchased the content from which the illegal copy was produced.

Digital data authentication method

This invention provides a method for identifying a purchaser who purchased content from which an illegal copy was produced. A provider system encrypts a content purchased by the purchaser using a public key of a purchaser system and sends the encrypted content to the purchaser system. The purchaser system creates a digital signature of the content with the use of a private key of its own and embeds the created digital signature into the received content. When an illegal copy is found, the provider system verifies the digital signature, embedded in the illegal copy as a digital watermark, to identify the purchaser who purchased the content from which the illegal copy was produced.

Growing community of inventors

Hachiohji, Japan

Hisashi Toyoshima