Abstract: A recording and reproduction apparatus for preventing illegitimate use of contents. A recording medium stores an inherent number in an unrewritable area. The recording apparatus writes media key data and an encrypted content onto the recording medium. The media key data includes encrypted media keys generated by (i) for each of unrevoked reproduction apparatuses, encrypting a media key using a device key of the unrevoked reproduction apparatus respectively, and (ii) for each of revoked reproduction apparatuses, encrypting detection information using a device key of the revoked reproduction apparatus. The reproduction apparatus decrypts the encrypted media key using a device key to generate a decryption media key, judges whether the decryption media key is the detection information, and prohibits the encrypted content recorded on the recording medium from being decrypted when judged in the affirmative.

Abstract: A theft prevention system capable of preventing theft of a target object by disabling the authorized key of the target object in the case where the authorized key has been stolen. When the authorized key is lost, a mobile telephone instructs a vehicle control device to set a warning mode. On receipt of this warning mode instruction, the vehicle control device sets warning mode, generates an electronic key, and transmits the generated electronic key to the mobile telephone, which receives and stores the electronic key. Once the warning mode is set in the vehicle, locking and unlocking are only possible using the electronic key. If the authorized key is found, the mobile telephone instructs the vehicle control device to set the normal mode. Upon receipt of this normal mode instruction, the vehicle control device sets the normal mode in the vehicle.

Abstract: A parameter generation apparatus for generating parameters causing no decryption error for an NTRU cryptosystem so that an encrypted communication can be carried out between an encryption apparatus and a decryption apparatus in a secure and reliable manner. The parameter generation apparatus includes: a provisional parameter generation unit operable to generate a set of provisional parameters that do not cause any decryption errors, based on error condition information that is provided in advance, the error condition information indicating a condition for causing no decryption error; and an output parameter generation unit operable to generate an output parameter that does not cause any decryption errors, using the set of provisional parameters, based on a lattice constant that is calculated from the set of provisional parameters.

Abstract: An aggregation system aggregates contents recorded on a plurality of recording mediums and recording them onto another recording medium while protecting the copyrights of the contents is provided. The aggregation system includes an aggregation apparatus and a reproduction apparatus. The aggregation apparatus obtains a main content from an optical disc, obtains a sub content from a memory card, and aggregates the obtained main content and sub content and records them onto a portable medium. The reproduction apparatus obtains the main content from the optical disc, obtains reproduction control information for controlling reproduction of the main content, and reproduces the main content recorded on the optical disc based on the reproduction control information.

Abstract: In an encrypted communication system that includes a first and a second device, the first device encrypts a 1st key using a public key of the second device to generate 1st encrypted data, which is then transmitted to the second device, receives 2nd encrypted data from the second device, which is then decrypted using a secret key of the first device to obtain a 2nd key, and generates, based on the 1st and 2nd keys, a 1st encryption key for use in communication with the second device. The second device encrypts a 3rd key using a public key of the first device to generate the 2nd encrypted data, which is then transmitted to the first device, receives the 1st encrypted data, which is then decrypted using a secret key of the second device to obtain a 4th key, and generates, based on the 3rd and 4th keys, a 2nd encryption key for use in communication with the first device. The first and second devices perform encrypted communication using the 1st and 2nd encryption keys.

Abstract: An encrypted communication system, capable of performing processing with the speed higher than the conventionally achieved speed, includes an encryption device and a decryption device sharing parameters that satisfy p=3 and q=2^k (k: an integer of 2 or greater). The decryption device generates a public key and a private key using the parameters, the encryption device encrypts a plain text using the public key, and then, the decryption device decrypts the encrypted text using its own private key.

Abstract: A content recording/reproducing system, which records and reproduces a sub-content relating to a main content, includes a distribution device, first and second recording media, a recording device and a reproducing device. The first recording medium that is non-rewritable prestores key data based on which a public key is derivable, and the main content. The distribution device outputs verification information that includes the sub-content and is generated by applying a digital signature to relative information relating to the sub-content based on a secret key corresponding to the public key. The recording device acquires and records the verification information on the second recording medium that is rewritable.

Abstract: Disclosed is a digital work protection system enabling a content distributor to flexibly define usage patterns of content permitted for users. The system is composed of a recording device and a playback device. The recording device acquires a digital work, range information showing a permission range within which the digital work is permitted to be used, and a subrange key for each subrange, generates an encryption key using all the acquired subrange keys, encrypts the digital work based on the encryption key to generate encryption information, and writes the encryption information and the range information to a recording medium. The playback device reads the range information and the encrypted information from the recording medium, acquires a subrange key for each subrange, generates a decryption key using all the acquired subrange keys, decrypts the encrypted information based on the decryption key to generate a digital work, and plays the digital work.

Abstract: An information presentation system that simplifies entry of information relating to a package media of a user. The information presentation system includes a playback apparatus, a library information management apparatus, and a terminal apparatus. The playback apparatus reads an identifier identifying a content from a portable recording medium in which the content is recorded, and transmits the read identifier to the library information management apparatus via a network. The library information management apparatus receives the identifier, acquires attribute information, generates library information including the attribute information and the identifier, and stores the library information. Upon request by the terminal apparatus, the library information management apparatus generates presentation information based on the library information, and transmits the presentation information.

Abstract: A content reproduction system that allow the user to rent or purchase any desired contents for reproduction without depending on a predetermined type of information of the user. The content reproduction system includes: a recording medium storing a license ticket including an encrypted master key; and a reproduction apparatus that receives from the user a request for a selected content and the information of the selected content, acquires distribution content information corresponding to the selected content, stores it in association with the license ticket into the recording medium. When reproducing the content, the reproduction apparatus generates a content using an encrypted content decryption key and an encrypted content that are contained in the distribution content information, and using a master decryption key information corresponding to the distribution content information, and reproduces the generated content.

Abstract: An encryption transmission apparatus and an encryption reception apparatus avoid attack that takes advantage of a re-transmission request. A server apparatus encrypts a content key five times, thereby generating five encrypted content keys, calculates a hash value of the content key, and transmits the five encrypted content keys and the hash value. An image playback apparatus receives the five encrypted content keys and the hash value, decrypts the five encrypted content keys thereby generating five content keys, calculates hash values, each corresponding to the generated content keys, and compares the calculated hash values with the received hash value, respectively. If at least one of the five calculated hash values matches the received hash value, the corresponding content key is considered correct. Conversely, if none of the five calculated hash values matches the received hash value, it is considered a decryption error.

Abstract: A content playback apparatus prevents related content recorded on separate media that make up a virtual package from being played separately, thereby restricting playback of the content to only when the virtual package is assembled as intended by the creator, and protecting copyright of the content. A key obtaining unit obtains a second key, with use of key management information recorded on a recording medium on which related content relating to the encrypted content is also recorded. An information obtaining unit obtains the encrypted content and key generation information that relates to generation of the first key, from a source other than the recording medium. A key generation unit generates the first key with use of the second key and the obtained key generation information. A decryption unit decrypts the encrypted content with use of the first key.

Abstract: A contents linkage information delivery system for delivering a related content that is associated with another content. The system includes a first playback apparatus, a server for transmitting the related content, and a second playback apparatus for playing back the related content, which each communicate via a communications channel. The first playback apparatus includes a playback position information acquisition unit for acquiring time-base playback position information of the other content, a request input unit for receiving a user request, and a first transmission unit for transmitting the time-base playback position information. The server includes a first reception unit for receiving the time-base playback position information a related content acquisition unit for acquiring the related content based on the time-base playback position information, and a second transmission unit for transmitting the related content. The second playback apparatus includes a second reception unit.

Abstract: Provided is a content distribution system that prevents different keys to be derived between an encryption apparatus and a decryption apparatus. A random-number generating unit 112d, in an encryption apparatus 110d, generates a random number s, and a first function unit 113d generates a functional value G(s) of the random number s, and generates a verification value a and a shared key K from the functional value G(s). An encryption unit 114d generates a first cipher text c1 of the verification value a using a public-key polynomial h, and a second function unit 115d generates a functional value H(a,c1) of the verification value a and the first cipher text c1, and a random-number mask unit 116d generates a second cipher text c2=s xor H(a,c1). A decryption unit 123d, in a decryption apparatus 120d, decrypts the first cipher text c1 using a secret-key polynomial f, to generate a decryption verification value a?.

Abstract: A computer system that makes it difficult to analyze the content of a calculation. In the computer system, a power operation unit performs the following operations using the input data “a” and “b”: ga=ga mod n, gb=gb mod n. Next, in the computer system, a multiplication unit performs the following calculation using ga and gb: gab=ga×gb mod n. Next, in the computer system, a discrete logarithm calculation unit calculates ci mod pi?1 to satisfy gab=gci mod pi (i=1, 2, 3, . . . , k). Next, in the computer system, a CRT unit calculates “c” to satisfy ci=c mod pi?1 (i=1, 2, 3, . . . , k) using the Chinese remainder theorem CRT.

Abstract: The present invention pertains to a transmission apparatus for generating an encrypted text by encrypting a plaintext, which includes a parameter storage unit for storing a random parameter (the number of terms whose coefficients indicate 1) adapted to an encryption key and an encryption apparatus and a decryption apparatus; an encryption unit for generating, from the plaintext, the encrypted text using the encryption key and the random parameter stored in the parameter storage unit, complying with an encryption algorithm based on the NTRU™ method; and a key updating unit for updating the random parameter stored in the parameter storage unit and the encryption key, as time passes.

Abstract: A theft prevention system capable of preventing theft of a target object by disabling the authorized key of the target object in the case where the authorized key has been stolen. When the authorized key is lost, a mobile telephone 100 instructs a vehicle control device 300a to set a warning mode. On receipt of this warning mode instruction, the vehicle control device 300a sets warning mode, generates an electronic key, and transmits the generated electronic key to the mobile telephone 100, which receives and stores the electronic key. Once the warning mode is set in the vehicle, locking and unlocking are only possible using the electronic key. If the authorized key is found, the mobile telephone 100 instructs the vehicle control device 300a to set the normal mode. Upon receipt of this normal mode instruction, the vehicle control device 300a sets the normal mode in the vehicle. Once the normal mode is set in the vehicle, locking and unlocking are only possible using the authorized key.

Abstract: An encrypted communication system, capable of performing processing with the speed higher than the conventionally achieved speed, has an encryption device and a decryption device which share parameters that satisfy p=3 and q=2ˆk (k: an integer of 2 or greater) (S161), where the decryption device generates a public key and a private key using the parameters (S162-S165), the encryption device encrypts a plain text using the public key (S166-S170), and then, the decryption device decrypts the encrypted text using its own private key (S171-S173).

Abstract: An information presentation system simplifies entry of information relating to a package media of a user, and management of the information. The information presentation system is made up of a playback apparatus, a library information management apparatus, and a terminal apparatus. The playback apparatus reads an identifier identifying a content from a portable recording medium in which the content is recorded, and transmits the read identifier to the library information management apparatus via a network. The library information management apparatus receives the identifier, acquires attribute information showing attributes of the content identified by the identifier, generates library information including the attribute information and the identifier, and stores the library information. Further, upon request by the terminal apparatus, the library information management apparatus generates presentation information based on the library information, and transmits the presentation information.

Abstract: A data converter (1) capable of reducing a size of the total implementation in a device is a processing apparatus that performs secret converting processing predetermined to input data with 64 bits, the data converter including a finite field polynomial cubing unit (10), data integrating units (11a) to (11d), (12) and (13), a first converter (14), a second converter (15), a data splitting unit (16), and a data integrating unit (17). The finite field polynomial cubing unit (10) performs cubing, on the 32 bits data, in the polynomial residue class ring with a value in the finite field GF (28) as a coefficient and respectively outputs data with 32 bits.