Kabushiki Kaisha Toshiba

Toshiba Solutions Corporation

Matsushita Electric Industrial Co., Ltd.

Panasonic Corporation

Takehisa Kato

Naoki Endoh

Koichi Hirayama

Norikazu Hosaka

Minako Tada

Makoto Tatebayashi

Hisashi Yamada

Yoshihiro Fujii

Kenjiro Endoh

Shingo Miyazaki

Motoji Ohmori

Hiroaki Unno

Taku Kato

Tadashi Kojima

Hideo Shimizu

Koji Okada

Naoki Endo

Yoshihisa Fukushima

Akihiro Kasahara

Yukihito Oowaki

Kenji Shimoda

Toru Kambayashi

Masao Suga

Atsushi Masuda

Kazunori Ohuchi

Takuya Yoshida

Akio Okazaki

Masatoshi Sekine

Yasuhiko Suzuki

Sunao Wada

Hiroshige Fujii

Hiroaki Nishi

Taku Katoh

Kenichi Hiramatsu

Daigo Yoshii

Akira Toshima

Koichi Noguchi

Koji Mikami

A purchaser apparatus stores 'anonymous order information including an order ID and purchaser identity verifying information' and 'purchaser identity proving secret information'. A shop apparatus stores &#x201c;anonymous order information including an order ID and purchaser identity verifying information&#x201d;. If necessary, a purchaser sends a request including an order ID and zero knowledge proving information that a purchaser knows the purchaser identity proving secret information, from a purchaser apparatus to a shop apparatus. A shop apparatus verifies the zero knowledge proving information, based on purchaser identity verifying information retrieved from an order ID included in the request. Therefore, the unlinkability for past use is eliminated if necessary, and inconvenience caused by the unlinkability is eliminated.

Shop apparatus and purchaser apparatus

A device that relieves a service provider of the burden of managing personal information. A group administration organization device admits a user device to an authorized group by request and sends authority permission information to the user device. The user device holds the authority permission information received from the group administration organization device and, on access, sends authority proof information created from the authority permission information using a group signature scheme to a service provider device as requested by it. The service provider device, upon being accessed, requests the authority proof information and verifies the authority proof information received from the user device in accordance with the request on the basis of the group signature scheme. When the verification result indicates validity, the service provider device provides a service. Thus, there is no need for the service provider to manage personal information of the user because the user device proves to the service provider device using the group signature scheme that it belongs to the authorized group.

Access control system, device, and program

A content distribution/browsing system is disclosed. First to (m&#x2212;1)th encrypted content items E(K, C&#x2225;K), . . . , E(K, C&#x2225;K) contain second to m-th (next in order) sharing keys K, . . . , K, respectively. When desirous of browsing an (i+1)th content item C, the (i+1)th sharing key Kis acquired by browsing an immediately preceding i-th content item C.

Content distribution/browsing system, content distribution apparatus, content browsing apparatus and program

A secret sharing apparatus according to the present invention is based on a (k,n)-threshold scheme with a threshold of at least 4 but is still operational with a threshold of at least 2. The secret sharing apparatus generates a generator matrix (G) of GF(2) in which any k of n column vectors are at a full rank, divides secret information into n&#x2212;1 pieces to generate divided secret data (K(1), . . . , K(n&#x2212;1)), generates random data (U(0,1), . . . , U(k&#x2212;2,n&#x2212;1)), calculates the product of matrixes of the divided secret data, the random data, and the generator matrix (G), assigns the j&#xd7;(n&#x2212;1)+ith column of the calculation result to sharing partial data (D(j,i)) to calculate sharing partial data (D(j,1)), generates header information (H(j)), and individually distributes n pieces of sharing information (D(0), . . . , D(n&#x2212;1)) made up of the header information (H(j)) and sharing partial data (D(j,i)) to n storage apparatuses.

Secret sharing apparatus, method, and program

A secret sharing device of (k, n) threshold scheme creates a generator matrix G, first divided secret data, and random number data, calculates shared partial data based on the product of matrices with the random number data, the divided secret data, and the generator matrix G, and delivers the shared information formed by the shared partial data and the header information individually to the storage units. The secret sharing device calculates a recovery matrix and multiplies the shared information by the recovery matrix, hence to recover the secret information.

Secret sharing device, method, and program

A user apparatus cannot acquire as many distribution keys K, . . . as a threshold value, to restore a content encryption key K, unless it decrypts as many encrypted sub-content items as the threshold value after it has played back a sub-content item SC. The user apparatus monitors the state in which the sub-content is being played back. It outputs a warning when the sub-content is in fast-forwarding state or skipping state. If the playback state is not returned to one before the fast forwarding or skipping, in spite of the warning, the user apparatus will erase the distribution keys acquired in the fast-forwarding state or skipping state.

User apparatus and program

A group administration organization device admits a user device to an authorized group by request and sends authority permission information to the user device. The user device holds the authority permission information received from the group administration organization device and, on access, sends authority proof information created from the authority permission information using a group signature scheme to a service provider device as requested by it. The service provider device, upon being accessed, requests the authority proof information and verifies the authority proof information received from the user device in accordance with the request on the basis of the group signature scheme. When the verification result indicates validity, the service provider device provides a service. Thus, there is no need for the service provider to manage personal information of the user because the user device proves to the service provider device using the group signature scheme that it belongs to the authorized group.

On a recording medium, first information obtained by enciphering data with the first key and second information obtained by enciphering the first key with each of the predetermined second keys are recorded. A deciphering method is characterized by comprising the steps of inputting the first and second information, deciphering the first key using at least one of the second keys, determining by a specific method that the obtained first key is correct, and then deciphering the data using the first key to obtain the data.

Method and apparatus of enciphering and deciphering data using keys enciphered and deciphered with other keys

Each embodiment of this invention implements step-by-step and empirical authentication of devices upon digital authentication among a plurality of devices. Each of a plurality of authentication devices of each embodiment can unidirectionally generate a hash value of a low experience rank from a hash value of a high experience rank, and receives a set of high experience rank and hash value in accordance with an experience. Upon receiving a certification request of the experience rank from another authentication device, the authentication device transmits a corresponding hash value to the authentication device as a request source. Upon sending a certification request of an experience rank to another authentication device, the authentication device verifies a hash value obtained from the other authentication device on the basis of a self hash value. In this way, the authentication devices authenticate each other's experience ranks.

System of authentication, apparatus, program and method

A source of MPEG2 video data is connected with a dedicated AV device or personal computer by means of an IEEE 1394 interface. A transmission unit in the source has an IEEE 1394 encryption unit and a sending I/F unit. A reception unit varies between the dedicated AV unit and the personal computer. In the reception unit of the dedicated AV device, a receiving I/F unit and a decryptor are integrally incorporated into one semiconductor chip and an MPEG2 decoder is incorporated into one semiconductor chip. In the reception unit of the personal computer, the receiving I/F unit is formed of one semiconductor chip, and the decryptor connected to the I/F unit through a bus, and the MPEG2 decoder are formed of one semiconductor chip. Thus, data before decryption will not appear on the bus, which prevents MPEG2 video data from being taken out of the computer for illegal copying purposes. In addition, the reception unit is made to have a different physical configuration depending on whether it is to be mounted in the dedicated AV device or the personal computer. This will prevent the reception unit (including the decryptor) of the dedicated AV device from being connected in the personal computer in place of its associated reception unit (excluding the decryptor).

Digital data reproduction device

In an embodiment, a copy-guard system is provided that includes a decoding section for decoding digital data, which is encoded and error-correction-coded, from an information recording medium in which key information encoded for the digital data is recorded, an encoded digital data acquisition section for acquiring digital data encoded by error-correcting the digital data decoded by the decoding section, a detection section for detecting an error position and an error symbol value of the encoded digital data, identification information detection section for detecting an identification information representing whether the information recording medium is original or copied and which is replaced with a part of the digital data encoded and error-correction-coded, based on the error position and the error symbol value detected by the detection section, a determination section for determining whether a copy of the information recording medium is protected, and a copy protection section.

Copy-guard system and information recording medium used in the same system

This invention protects the unauthorized copy of multimedia data, recorded on an information recording medium, by using electronic watermark information and key information. The electronic watermark information embedded in the multimedia data is extracted by an electronic watermark extraction unit on the decryption system side. A disk key is obtained using the electronic watermark information and a part master key. The multimedia data is decrypted using the resultant disk key.

Copy protection apparatus and information recording medium used in this copy protection apparatus

This invention discloses an information sending system for sending encrypted information which can be decrypted in units of parts of information. This information sending system includes information segmentation means for segmenting information into a plurality of blocks, first encryption means for encrypting more than one blocks of the plurality of blocks using a first key, second encryption means for encrypting more than one blocks of the blocks other than those encrypted by the first encryption means using a second key, and information sending means for sending outgoing information including the blocks encrypted by the first encryption means and those encrypted by the second encryption means.

Information sending system and method for sending encrypted information

A device to be used with digital data copying apparatus for preventing fraudulent copies of a digital data is disclosed. The digital data includes an encrypted data main body and encrypted copy management information for controlling permission with regard to copying the data main body. A determining section determines if permission be granted for copying the digital data or not depending on if the copy management information satisfies predetermined requirements or not. A prohibition processing section prohibits any operation of effectively copying the digital data when the determining section determines that permission should not be granted for copying the digital data.

Growing community of inventors

Yokohama, Japan

Takehisa Kato