Panasonic Corporation

Matsushita Electric Industrial Co., Ltd.

Satomi Yamamichi, Legal Representative

Motoji Ohmori

Keiko Yamamichi, Legal Representative

Masami Yamamichi, Legal Representative

Yuichi Futa

Masato Yamamichi

Makoto Tatebayashi

Masaya Yamamoto

Atsushi Saso

Kazuhisa Watanabe

Naoaki Yamamoto

Toshihisa Nakano

Kaoru Murase

Makoto Usui

Kaoru Yokota

Shunji Harada

Hiroshi Hamasaka

Yasushi Uesaka

Masahiro Mambo

Hiroyuki Shizuya

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.

Digital work protection system, recording apparatus, reproduction apparatus, and recording medium

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.

Parameter generation apparatus, encryption system, decryption system, encryption apparatus, decryption apparatus, encryption method, decryption method, and program thereof

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.

Securely aggregating content on a storage device

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.

Encrypted communication system and communication device

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.

Encryption system, encryption device, decryption device, program, and integrated circuit

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. The reproducing device acquires the key data from the first recording medium and the verification information from the second recording medium, derives the public key from the key data, verifies the verification information using the public key, and reproduces the sub-content if the verification succeeds.

Content recording/reproducing system, distribution device, reproducing device, and recording device

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.

Information presentation system, management device, and terminal device

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.

Encryption communication system

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.

Content playback apparatus, content playback method, and program

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, in an encryption apparatus, generates a random number s, and a first function unitgenerates 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 unitgenerates a first cipher text cof the verification value a using a public-key polynomial h, and a second function unitgenerates a functional value H(a,c) of the verification value a and the first cipher text c, and a random-number mask unitgenerates a second cipher text c=s xor H(a,c). A decryption unit, in a decryption apparatus, decrypts the first cipher text cusing a secret-key polynomial f, to generate a decryption verification value a'. A third function unit 124generates a functional value H(a&#x2032;,c) of the decryption verification value a&#x2032; and the first cipher text c, and a random-number mask removal unitgenerates a decryption random number s&#x2032;=cxor H(a&#x2032;,c). A fourth function unitgenerates a hash functional value G(s&#x2032;) of the decryption random number s&#x2032;, and generates a verification value a&#x2033; and a shared key K&#x2032; from the functional value G(s&#x2032;) A comparison unitoutputs the shared key K&#x2032; if the decryption verification value a&#x2032; is equal to the verification value a&#x2033;.

Key agreement system, shared-key generation apparatus, and shared-key recovery apparatus

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': g=gmod n, g=gmod n. Next, in the computer system, a multiplication unit performs the following calculation using gand g: g=g&#xd7;gmod n. Next, in the computer system, a discrete logarithm calculation unit calculates cmod p&#x2212;1 to satisfy g=gmod p(i=1, 2, 3, . . . , k). Next, in the computer system, a CRT unit calculates &#x201c;c&#x201d; to satisfy c=c mod p&#x2212;1 (i=1, 2, 3, . . . , k) using the Chinese remainder theorem CRT.

Computer system, computer program, and addition method

A data converter () 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 (), data integrating units () to (), () and (), a first converter (), a second converter (), a data splitting unit (), and a data integrating unit (). The finite field polynomial cubing unit () performs cubing, on the 32 bits data, in the polynomial residue class ring with a value in the finite field GF (2) as a coefficient and respectively outputs data with 32 bits.

Growing community of inventors

Ota, Japan

Satomi Yamamichi, Legal Representative