Abstract: A transmission device including: copy unit that extracts part or all of partial contents, as tracking information, from a content, and copies the extracted tracking information, thereby generating pieces of tracking information; candidate information obtaining unit that obtains pieces of candidate information respectively corresponding to the pieces of tracking information; evidence information obtaining unit that obtains evidence information generated dependently on a piece of candidate information selected by the reception device from among the pieces of candidate information; hash generating unit that generates hash values respectively in accordance with the pieces of candidate information; embed unit that embeds the hash values respectively into the pieces of tracking information, and embeds the evidence information into each piece of tracking information; and transmit unit that transmits each piece of tracking information in which a hash value and the evidence information have been embedded.

Abstract: A content distribution system for transferring contents between transmission device and reception device. The transmission device includes: key obtaining unit that obtains, from reception device, public keys and public key identifiers; watermark embedding unit that embeds a different public key identifier, as electronic watermark, into each of contents that are identical in substance; an encryption unit that encrypts contents using public keys to generate encrypted contents; and transmission unit that transmits encrypted contents to reception device. The reception device includes: key storage unit storing public keys, public key identifiers, and a private key that makes a pair with one of the public keys; key transmission unit that transmits public keys and public key identifiers to the transmission device; content receiving unit that receives encrypted contents from transmission device; and decryption unit that obtains a content from the received encrypted contents, using the private key.

Abstract: A management apparatus reduces the number of pieces of unique information each not generated from another piece of unique information, among unique information being bases of keys assigned to managed apparatuses. The management apparatus calculates, for nodes in layers other than tree structure leaves, subsets of apparatus identifiers subordinate to the nodes, searches for a subset wholly containing another subset in the lowermost layer other than a leaf layer from an immediately-upper layer and mutually associates these subsets, searches for another subset wholly containing the containing subset from a same or an immediately-upper layer and mutually associates these subsets, controls this processing to repeat up to the uppermost layer, controls these processings to repeat on all subsets in the lowermost layer, makes unique information correspond to subsets in the lowermost layer, and makes information derivatively obtained from the unique information correspond to subsets connected due to the associating.

Abstract: A quantum key distribution protocol is provided that reduces the maximum value of the leaked information amount over the same distance when an adversary makes a photon number splitting attack more than the reduction by the BB84 protocol and the SARG protocol, by making use of the advantages of the BB84 protocol and the SARG protocol. By properly proportioning the existing BB84 protocol and the SARG protocol in accordance with the rate determined by the communication distance between the sender and the receiver of the coherent light, a protocol that is more robust against photon number splitting attack than the known existing protocols can be realized, and long distance quantum key distribution, which was not possible until now, becomes possible.

Abstract: A copyright protection system is provided that keeps manufacturing costs down regardless of the total number of playback apparatuses belonging to the system. In this system, a device key generating unit of a key management apparatus performs a modular exponentiation operation on a random number with an inverse element of a product of predetermined prime numbers, so as to generate and distribute device keys to playback apparatuses in one-to-one correspondence. A key revocation data generating unit generates, as key revocation data, information identifying the prime numbers used by an unrevoked playback apparatus to generate a decryption key from its device key and distributes the key revocation data along with an encrypted content to each playback apparatus. Playback apparatuses each attempt to generate a description key based on the key revocation data, and only those playback apparatuses that have successfully generated a decryption key are able to decrypt the encrypted content.

Abstract: An authentication system for mutual authentication between a terminal and a server characterized by the fact that the terminal comprises a memory means that pre-stores an authentication information P? for terminal storage; a concatenation means that yields a value P using a specific calculation formula with the input of the authentication information P? read from the memory means and a password entered for authentication; a mask operation means that yields a value Y1 using a specific calculation formula with the input of value P and an internally generated random number, and then sends Y1 to the server; and a master key generation means that yields a value MK using a specific calculation formula with the input of value P, an internally generated random number and a value Y2 received from the server, and the server comprises a memory means that pre-stores a password verification data H for server registration; a mask operation means that yields a value Y2 using a specific calculation formula with the input of

Abstract: An unauthorized apparatus detection device detecting clones of a playback device. In a management server, a reception processing unit acquires a user terminal identifier and a first random number of a user terminal, judges whether a second management server random number, which is stored in a storage unit in correspondence with the user terminal identifier, matches the first user terminal random number. If the two fail to match, a display unit displays a message indicating that a clone exists. If the two match, a terminal information generation unit generates a new random number, and writes the generated random number as the second random number in the storage unit. A transmission processing unit transmits the generated random number to the user terminal via a transmission/reception unit and the user terminal updates the first user terminal random number to the generated random number.

Abstract: A system and method for multi-spectral image capture of a first scene includes acquiring a first series of images of the first scene with one or more image acquisition systems and filtering each of the first series of images of the scene with a different non-interference filter, illuminating each image of the first series of images with a different illuminant, or acquiring each of the images of the first series of images with a different image acquisition system. Each of the image acquisition systems has at least one color channel, each of the non-interference filters has a different spectral transmittance, and each of the illuminants has a different spectral power distribution.

Abstract: A quantum key distribution protocol is provided that reduces the maximum value of the leaked information amount over the same distance when an adversary makes a photon number splitting attack more than the reduction by the BB84 protocol and the SARG protocol, by making use of the advantages of the BB84 protocol and the SARG protocol. By properly proportioning the existing BB84 protocol and the SARG protocol in accordance with the rate determined by the communication distance between the sender and the receiver of the coherent light, a protocol that is more robust against photon number splitting attack than the known existing protocols can be realized, and long distance quantum key distribution, which was not possible until now, becomes possible.

Abstract: To provide an unauthorized device detection system capable of finding and specifying a device that was manufactured or altered unauthorizedly. A DVD player 400a writes its own device ID to a memory card 200a. When a user purchases content, a register device 300 reads a media ID and the device ID from the memory card 200a, and transmits the media ID and the device ID to a management server device 100. The management server device 100 calculates, based on pairs of media IDs and device IDs stored beforehand and the received pair of media ID and device ID, a total number of media IDs corresponding to the received device ID, and compares the calculated total number with a threshold value. If the total number exceeds the threshold value, the management server device 100 judges that the DVD player identified by the received device ID is an unauthorized device.

Abstract: An unauthorized apparatus detection device, playback device, unauthorized apparatus detection system, information collection device, unauthorized apparatus detection method, a program, recording medium, apparatus information update method, and integrated circuit can detect clones of a playback device. In a management server 2, a reception processing unit 241 acquires a user terminal identifier and a first random number from a user terminal targeted for unauthorized apparatus detection, judges whether a second management server random number, which is stored in a storage unit 23 in correspondence with the user terminal identifier, matches the first user terminal random number. If the two fail to match, a display unit 22 displays a message indicating that a clone exists. If the two match, a terminal information generation unit 243 generates a new random number, and writes the generated random number as the second random number in the storage unit 23.

Abstract: A transmission device including: copy unit that extracts part or all of partial contents, as tracking information, from a content, and copies the extracted tracking information, thereby generating pieces of tracking information; candidate information obtaining unit that obtains pieces of candidate information respectively corresponding to the pieces of tracking information; evidence information obtaining unit that obtains evidence information generated dependently on a piece of candidate information selected by the reception device from among the pieces of candidate information; hash generating unit that generates hash values respectively in accordance with the pieces of candidate information; embed unit that embeds the hash values respectively into the pieces of tracking information, and embeds the evidence information into each piece of tracking information; and transmit unit that transmits each piece of tracking information in which a hash value and the evidence information have been embedded.

Abstract: A content distribution system for transferring contents between transmission device and reception device. The transmission device includes: key obtaining unit that obtains, from reception device, public keys and public key identifiers; watermark embedding unit that embeds a different public key identifier, as electronic watermark, into each of contents that are identical in substance; an encryption unit that encrypts contents using public keys to generate encrypted contents; and transmission unit that transmits encrypted contents to reception device. The reception device includes: key storage unit storing public keys, public key identifiers, and a private key that makes a pair with one of the public keys; key transmission unit that transmits public keys and public key identifiers to the transmission device; content receiving unit that receives encrypted contents from transmission device; and decryption unit that obtains a content from the received encrypted contents, using the private key.

Abstract: A copyright protection system is provided that keeps manufacturing costs down regardless of the total number of playback apparatuses belonging to the system. In this system, a device key generating unit of a key management apparatus performs a modular exponentiation operation on a random number with an inverse element of a product of predetermined prime numbers, so as to generate and distribute device keys to playback apparatuses in one-to-one correspondence. A key revocation data generating unit generates, as key revocation data, information identifying the prime numbers used by an unrevoked playback apparatus to generate a decryption key from its device key and distributes the key revocation data along with an encrypted content to each playback apparatus. Playback apparatuses each attempt to generate a description key based on the key revocation data, and only those playback apparatuses that have successfully generated a decryption key are able to decrypt the encrypted content.

Abstract: A management apparatus reduces the number of pieces of unique information each not generated from another piece of unique information, among unique information being bases of keys assigned to managed apparatuses. The management apparatus calculates, for nodes in layers other than tree structure leaves, subsets of apparatus identifiers subordinate to the nodes, searches for a subset wholly containing another subset in the lowermost layer other than a leaf layer from an immediately-upper layer and mutually associates these subsets, searches for another subset wholly containing the containing subset from a same or an immediately-upper layer and mutually associates these subsets, controls this processing to repeat up to the uppermost layer, controls these processings to repeat on all subsets in the lowermost layer, makes unique information correspond to subsets in the lowermost layer, and makes information derivatively obtained from the unique information correspond to subsets connected due to the associating.

Abstract: An authentication system for mutual authentication between a terminal and a server characterized by the fact that the terminal comprises a memory means that pre-stores an authentication information P? for terminal storage; a concatenation means that yields a value P using a specific calculation formula with the input of the authentication information P? read from the memory means and a password entered for authentication; a mask operation means that yields a value Y1 using a specific calculation formula with the input of value P and an internally generated random number, and then sends Y1 to the server; and a master key generation means that yields a value MK using a specific calculation formula with the input of value P, an internally generated random number and a value Y2 received from the server, and the server comprises a memory means that pre-stores a password verification data H for server registration; a mask operation means that yields a value Y2 using a specific calculation formula with the input of

Abstract: An optical switch has plural incident side optical fibers 4a; plural main emitting side optical fibers 7a respectively arranged so as to be opposed to the respective incident side optical fibers 4a; a single preliminary emitting side optical fiber 7b; a reflection means 5 moved so as to be positioned with respect to one of the incident side optical fibers 4a, and reflecting an optical signal from the incident side optical fiber 4a to the preliminary emitting side optical fiber 7b; and a driving means 21 for moving the reflection means 5 with respect to each incident side optical fiber 4a and reflecting the optical signal from this incident side optical fiber 4a by the reflection means 5 and able to set this optical signal to be incident to the preliminary emitting side optical fiber 7b.

Abstract: A digital signature system comprises a center computer and a first and second terminal devices which can communicate with each other. The center computer generates and outputs a signing-key for a signer and a verification-key for a verifier. The first terminal device accepts the signing-key, generates a digital signature for a digital data to be signed using the signing-key, and outputs the digital signature. The second terminal device accepts the verification-key, the signer's identification code (e.g. the unique code of the signer), an identification code of the digital data and the digital signature, and verifies the validity of the digital signature using the verification-key, the identification code of the digital data and the signer's identification code.