Fujitsu Corporation

Other

Yasutsugu Kuroda

Etsuo Ono

Jun Kamada

Naoya Torii

Kazue Sako

Hiroshi Miyauchi

Seiichi Domyo

Hiroyuki Ando

Hiroaki Kikuchi

Hiroyoshi Tsuchiya

Seiko Kanno

Masashi Yamazaki

Satoru Torii

Masahiro Komura

Hideyuki Aikawa

Shoko Iwase

Ichirou Morita

Takashi Yoshioka

Bintatsu Noda

Ichir{overscore (o)}u M{overscore (o)}rita

A user support system for cryptographic communication includes a key storage for storing keys used for deciphering, a deciphering part for deciphering an enciphered communication text into a deciphered communication text using a key, and a controller for starting the deciphering part only when an input communication text is the enciphered communication text and for supplying the key that is necessary for the deciphering in the deciphering part by retrieving the key from the key storage.

User support system for cryptographic communication in network systems

A storage apparatus includes a key management unit for managing an individual key unique to the apparatus and a common key shared with other storage apparatuses, and an encryption unit for performing an encrypting process or verifying data for performing the encrypting process on electronic data stored in the apparatus to which the unit belongs using the individual key, and performing the encrypting process or verifying the data on the electronic data transmitted to or received from another apparatus using the common key. Thus, the apparatus communicates data using an applicable common key in a local environment and a global environment, appropriately manages a key in each environment, and guarantees the security of the electronic data.

Electronic data storage apparatus with key management function and electronic data storage method

An electronic document is registered as electronic original data in an apparatus different from the computer environment of a user. At this time, a registration certificate for uniquely identifying the electronic original data is issued, and the user accesses the electronic original data using the issued registration certificate.

Apparatus and method for managing electronic original data

A user support system for cryptographic communication includes a key storage unit for storing keys used for deciphering, a deciphering unit for deciphering an enciphered communication text into a deciphered communication text using a key, and a controller for starting the deciphering unit. only when an input communication text is the enciphered communication text, and for supplying the keys that is necessary for the deciphering in the deciphering unit, by retrieving the key from the key storage.

An information storage device in which a plurality of storage media having different accessibility is provided with a unit for controlling the retrieval of a portable storage medium which can be retrieved from an information storage device by selecting, at a request to retrieve the portable storage medium, the storage medium either as storing the body of a file and the data for use in accessing the file or as storing only the body of the file. The information storage device stores in and moves to a storage medium at an appropriate level the data for use in accessing a file depending on the situation.

File management apparatus and method

The digital signatures of users A and B are created for a transaction document which states the contents of a transaction between the users A and B, and they are sent to a transaction proof device of a notary public being a third party, together with the transaction document. Thus, the users A and B and the notary public share information, and the notary public can objectively prove the transactional contents, etc.

Apparatus and method for proving transaction between users in network environment

An electronic data storage apparatus includes a data storage unit for storing electronic data; an authentication information generation unit for generating authentication information used in detecting an amendment made to the stored electronic data; and an authentication information data output unit for outputting the electronic data after adding to the electronic data the authentication information generated for the electronic data. When an authorization unit authorizes the electronic data storage apparatus after it is determined that the specification of the electronic data satisfies a predetermined condition, or when mutual authentication is performed between electronic data storage apparatuses, the electronic data storage apparatus stores the data. Thus, the electronic data can be protected from being illegally amended or deleted, and can be safely stored in a format in which sufficient legal evidence can be maintained on the electronic data.

Electronic data storage apparatus, system and method

By storing an authenticator created from a data file in a secure area usually unaccessible, the alteration of the data file can be detected. Furthermore, by designating the data file as a main-file and creating authenticators from various kinds of sub-files related to the main-file, the size of the secure area where the authenticators are stored, can be reduced.

Apparatus method and computer readable storage medium with recorded program for managing files with alteration preventing/detecting functions

A key recovery condition encryption apparatus includes a hashing unit, a first concatenating unit, and a condition information encryption unit. The hashing unit calculates a hash value on the basis of a hash function using a key recovery information text serving as information necessary for performing key recovery. The first concatenating unit concatenates the hash value from the hashing unit to the key recovery condition. The condition information encryption unit encrypts a concatenating result from the first concatenating unit by using a first encryption key. Also is disclosed a key recovery condition decryption apparatus for decrypting the encrypted data from the above encryption apparatus.

Key recovery condition encryption and decryption apparatuses

The present invention has an object to overcome problems of a key recovery system using a conventional KRF system and to achieve efficient operation of the overall key recovery system. A key recovery system of the present invention includes check units,for checking whether a user has a recovery authorization for a common key KS, on the basis of a recovery condition RC specified by a recovery condition index RCI which is added to an encrypted message (encrypted message obtained by encrypting the common key KS with a public key KRCpub) supplied from a terminal (,to,) of the user concerned, and a key recovery control unit,which is provided separately from the check units,and decrypts the encrypted message with a private key KRCpri paired with the public key KRCpub to recover the common key. The check unit,supplies the common key KS recovered in the key recovery control unit,to the user concerned only when the user has the recovery authorization.

Key recovery system and key recovery method

In an authentication system for companies, a server appends suitable verification data to an electronic document to be circulated through terminal units for persons in charge. Each terminal is allocated a unique function in advance and applies it to the verification data in turn when receiving the document. Upon receipt of the document that has been circulated through the persons in charge, the server examines the function-applied value appended to the document to determine whether the document has been circulated correctly through the persons in charge, or via the correct route.

System and method of authentication of digital information

A key recovery information distribution device is provided between a recoverer device and a key recovery device, recovers a data key for the recoverer device, and reduces the load of the recoverer device. Data is encrypted using the data key and stored with key recovery information. The recoverer device which decrypts the encrypted data distributes the key recovery information to key recovery devices through the key recovery information distribution device to recover key information. A recoverer is authenticated directly between the key recovery device and the recoverer device, and then the key information is transmitted to the recoverer device, and the recoverer device recovers the data key.

Key recovery system

In a security level control apparatus for controlling a security level of a communication established between communication parties, this security level control apparatus is arranged by employing a security level recognizing unit and a security level setting unit. The security level recognizing unit recognizes a security level notified from a communication party. The security level setting unit sets the security level recognized by the security level recognizing unit as a security level for the security level control apparatus. In accordance with this security level control apparatus, the security level of the communication party recognized by the security level recognizing unit is first set as the security level for the security level control apparatus. As a result, the communication can be established between the communication parties without presetting the security level.

Security level control apparatus and method for a network securing

A cryptographic information repeater installed in a system for transmitting information among a plurality of subscribers interconnected by a communication line. The repeater acts as a managing center for managing cryptokeys. Therefore, confidentiality can be effectively preserved because a common secret key is not shared by all the subscribers. When some subscriber withdraws or a new user enters, it is only necessary to update the database concentrated in the cryptographic information repeater. Therefore, if the number of subscribers increases, it will not be cumbersome to manage the data.

Growing community of inventors

Kawasaki, Japan

Yasutsugu Kuroda