Hitachi, Ltd.

Tokyo, Japan

Kunihiko Miyazaki

Kazuo Takaragi

Hiroshi Yoshiura

Ryoichi Sasaki

Seiichi Susaki

Takeshi Matsuki

Shinji Itoh

Tsutomu Matsumoto

Mitsuru Iwamura

Hisashi Toyoshima

Yasuo Hatano

Masashi Takahashi

Dai Watanabe

Hisayoshi Sato

Hiroyuki Kurumatani

Kouichi Tanimoto

Soichi Furuya

Narihiro Omoto

Kenji Matsumoto

Isao Echizen

Toshiyuki Moritsu

Mizuhiro Sakai

Yoji Shimizu

Yoshiharu Bessho

Toshiaki Arai

Yasuko Fukuzawa

Masato Arai

Naoki Hayashi

Kousuke Anzai

Yoshiaki Isobe

Yoko Hashimoto

Jun'ichi Taguchi

Katsuyuki Okeya

Hirokazu Aoshima

Hideo Noyama

Daisuke Miyamoto

Kazunori Nakano

Kosuke Anzai

Natsuki Watanabe

Hisanori Mishima

Kunihito Takeuchi

Yasuaki Kudo

Tomohisa Kumagai

Katsuko Nishioka

A data authenticity assurance method carried out by a management computer including: a first step of receiving the first data piece from the computer; a second step of selecting a plurality of second data pieces at predetermined intervals in chronological order from among the plurality of second data pieces held in the data holding part; a third step of performing an arithmetic operation for each of the hash values of the selected plurality of second data pieces; a fourth step of generating signature target data by combining the first data piece received from the computer with the hash values of the selected plurality of second data pieces; and a fifth step of generating a second data piece by assigning the digital signature to the signature target data by using the preset key, and holding the generated second data piece in chronological order sequentially in the data holding part.

Data authenticity assurance method, management computer, and storage medium

The present invention provides an electronic document authenticity assuring method in which a series of procedures concerning redactable signature are divided into procedures dependent on a document to be signed and procedures dependent on a redactable signature method. Further, the present invention provides program codes that realize the divided procedures and a system comprising apparatuses for implementing those program codes. According to the present invention, even when type of electronic document to be signed is changed or added to, it is sufficient to add a procedure dependent on a document to be signed, without changing procedures dependent on redactable signature methods. Similarly, even when a redactable signature method is to be changed or added, it is sufficient to add a procedure dependent on the redactable signature method without changing procedures dependent on document to be signed.

Electronic data authenticity assurance method and program

An encryption processing part of a controller of each of user devices specifies components of content as encryption target parts, creates an encryption key creation key by reading out a public key, for each of the encryption target parts, of a second user who is allowed to view the encryption target part, raising a secret key of an administrator of the content data to the power of the public key thus read out, and calculating a remainder, encrypts random numbers each corresponding to each of the encryption target parts by using the encryption key creation key, creates an encryption key for each of the encryption target parts, and encrypts, by using the encryption key created for each of the encryption target parts, each of the encryption target parts corresponding to the encryption key.

Encrypting device, decrypting device, information system, encrypting method, decrypting method, and program

A need exists for a technology for guaranteeing the authenticity of an electronic document, and an information disclosure system, which can guarantee the authenticity of a disclosed document and delete information regarded as inappropriate for disclosure. An electronic document is divided into components, and a random number generated from a seed value is concatenated to each of the components. A hash value is calculated for each of the components with which the random numbers have been concatenated. The calculated hash values are further concatenated using a hash function to generate data to which an digital signature is applied.

Electronic document authenticity guarantee method, and electronic document disclosure system

Disclosure of information is controlled selectively depending on users such that a plurality of users having different roles bearing no inclusive relation with one another can access the same area. Content is divided into a plurality of areas. For each of the areas obtained by division, secret keys (encryption/decryption keys in symmetric-key cryptography) are generated. The generated keys are encrypted using public keys in public-key cryptography, which are set in advance for the users depending on their respective roles. In the case where the content is to be disclosed to a plurality of users having different roles, the encryption of secret keys is performed separately for each user. These encrypted contents and encrypted secret keys are used to generate encrypted text.

Digital content encryption and decryption method and workflow system using digital content

According to the invention, techniques for authenticating that a digitally signed document is genuine. Specific embodiments according to the present invention can determine whether a digital signature was generated by a digital signature generator, or if the digital signature was generated by a third party posing as the digital signature generator. Specific embodiments can provide independent verification of digital signer identity based upon prior signed messages, time/date stamps, and the like. Techniques according to the present invention can be embodied in methods, apparatus, computer software and systems.

Digital signing method

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 managing digital signature includes the steps of preparing a signature log file storing signature log entry information, generating a new digital signature for a transmission message by reflecting, in the new digital signature, signature log entry information registered to the signature log file in the past; generating signature log entry information associated with the new digital signature and registering the signature log entry information to the signature log file; and preparing a user search file in addition to the signature log file; registering, to the user search file, user identifier information indicating a transmission destination of the transmitted digital signature and a transmission source of the received digital signature, with a correspondence established between the information, the user identifier information, and each signature log entry information in the signature log file.

Method of managing digital signature, apparatus for processing digital signature, and a computer readable medium for recording program of managing digital signature

An electronic document authenticity assurance technique and an information disclosure system both of which can compatibly realize the assurance of the authenticity of disclosure documents and the deletion of information inappropriate for disclosure. An electronic document is divided into constituent elements and an electronic signature is affixed to an arbitrary subset of a set including all the constituent elements. Otherwise, an electronic signature is affixed to data obtained by binding each of the constituent elements to information specifying the relationship between a respective one of the constituent elements and the structure of the electronic document. Otherwise, the hash values of the respective constituent elements are calculated and an electronic signature is affixed to data obtained by binding the calculated hash values together. Otherwise, random numbers generated for the respective constituent elements are bound together, then the hash values of the respective random-numbered constituent elements are calculated, and then an electronic signature is affixed to data obtained by binding the calculated hash values together.

Electronic document authenticity assurance method and electronic document disclosure system

A contents control method for controlling a process on the receiving side which is applied to contents transmitted from the transmitting side to the receiving side, includes a step of adding, when a predetermined block of the transmitted contents is an area where control information for controlling the process substance on the receiving side which is applied to the contents is added, the control information to the block. The method also includes a step of receiving a process designation concerning the transmitted contents, and a step of applying, when user information stored in a receiving side apparatus which receives the transmitted contents, or information concerning the receiving side apparatus satisfies conditions corresponding to the received process designation in the control information added to the block of the contents, a process corresponding to the process designation to the received block.

Method and system for contents control

The invention provides a method for verification having a structure that reflects reliability of a signature history properly for a hysteresis signature used for verification based on the signature history, and provides a method for arbitration and an arbitrator apparatus that solve a dispute on correctness of a signature based on the method for verification. Furthermore, the invention provides a method for managing history that mitigates the signature history management burden on a signer. Reliability is set on a signature forming record that is a component of a signature history, reliability of the signature history is calculated based on the set reliability, and the calculated reliability is output as reliability of a verification result. The invention provides a method for verification having a structure that reflects the reliability of a signature history properly and a method for arbitration and an arbitrator apparatus that solve a dispute on correctness of a signature. Furthermore, providing a signature history storage service apparatus mitigates the signature history storage burden on a signer.

Method for verifying a digital signature

A publication system effective and secure to the publication agency and a user is provided for the publication agency, and a signature verifying function using the published signature log entries is provided for the user. The publication agency publishes a signature log entry received from the users on the Web, and acquires a time-stamp at the time of the publication, and transmits the time-stamp together with a publication notice back to the user. The publication agency also has the signature log, and either discloses part of the log at regular intervals in a newspaper or the like, or produces publication-purpose data based on the signature log entry received from each user, and publishes the data in the newspaper. The publication agency, after the newspaper publication, transmits the signature log of the publication agency to the user.

Method and apparatus for publishing signature log entry

A symmetric-key cryptographic technique capable of realizing both high-speed cryptographic processing having a high degree of parallelism, and alteration detection. The invention includes dividing plaintext composed of redundancy data and a message to generate plaintext blocks each having a predetermined length; generating a random number sequence based on a secret key, generating a random number block corresponding to one of the plaintext blocks from the random number sequence, outputting a feedback value obtained as a result of operation on the one plaintext block and the random number block, the feedback value being fed back for using the operation on another plaintext block, and performing an encryption operation using the one plaintext block, random number block, and feedback value.

Method and apparatus for symmetric-key decryption

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

Growing community of inventors

Yokohama, Japan

Kunihiko Miyazaki