Kddi Corporation

Kyocera Corporation

Nippon Hoso' Kyokai

Shinsaku Kiyomoto

Toshiaki Tanaka

Tatsuo Shibata

Masaru Fukushima

Shuichi Sugie

Takeshi Kimura

Yutaka Miyake

Keigo Majima

Go Ohtake

Jun Kurihara

Hideki Kokubun

Yuto Nakano

A non-linear processor, which subjects an input value from a feedback shift register storing an internal state of a stream cipher to non-linear processing to output a key stream, is connected to internal registers, which store output values from a non-linear substitution circuit which subjects the input value to non-linear substitution processing. The non-linear processor is provided with an exclusive-OR unit, which is at an input end of each of the internal registers and carries out an operation of a random number generated from part of values stored in the feedback shift register and the output value of the non-linear substitution circuit to mask the output value of the non-linear substitution circuit, and another exclusive-OR unit, which is provided at an output end of the internal register and performs an operation to unmask the value stored in the internal register.

Non-linear processor, stream-cipher encrypting device, stream-cipher decrypting device, mask processing method, stream-cipher encrypting method, stream-cipher decrypting method, and program

A stream encryption device generates a first pseudo random number sequence from key information, generates a second pseudo random number sequence according to clock control performed according to the first pseudo random number sequence, and subjects it to a nonlinear function calculation, thereby generating a key stream. The stream encryption device performs XOR operation with a plain text so as to create an encrypted text.

Keystream encryption device, method, and program

A broadcast receiving apparatus comprises a broadcast receiving unit () for receiving a digital broadcast; a communication unit () for performing two-way communication through a network; an operation unitfor performing an acquisition operation of a key for decrypting an encrypted broadcast program received by the broadcast receiving unit; and an address generating unitfor generating an address of an acquisition location of the key which is accessible with the communication unit, by using program arrangement information corresponding to the broadcast program based on the acquisition operation of a key by the operation unit.

Address generating method and broadcast receiving apparatus

Provided is a system far receiving a initialization packet containing an initial vector for initializing stream encryption algorithm and an identifier of a key for decrypting an encrypted stream, initializing a decryption module, and decrypting the encrypted stream, wherein the system stores an identifier of a key which is needed to decrypt a next program in a initialization packet of a current program and informs a user of whether a desired key has been acquired or not at timing close to start time of the next program.

Stream generation method, broadcast receiving apparatus, and display method

A threshold secret sharing apparatus, a threshold secret sharing scheme, a secret information recovery apparatus a secret information recovery method, and a program thereof are provided using XOR computation, thereby offering a general (k,n) threshold secret sharing scheme with high computation speed. Secret information K is divided into (n&#x2212;1) divided pieces of secret information K(nis a prime number which is equal to or greater than a secret distribution number n). Furthermore, dummy secret information Kis generated. Moreover, random numbers R, which are mutually independent are generated. Then, pieces of shares are created using exclusive-OR (XOR) operations based upon the dummy secret information K, the divided piece of secret information K, and the random numbers R. The pieces of shares thus generated are concatenated so as to generate n shares S, thereby providing a (k,n) threshold secret sharing scheme.

Threshold secret sharing apparatus, threshold secret sharing scheme, secret information decryption method, and program for the same

A stream encryption device generates a first pseudo random number sequence from key information, generates a second pseudo random number sequence according to clock control performed according to the first pseudo random number sequence, and subjects it to a nonlinear function calculation, thereby generating a key stream. The stream encryption device performs XOR operation with a plain text so as to create an encrypted text. The stream encryption device performs an encryption process in units of words by using a clock controller. It includes: a first pseudo random number generation means to generate a first pseudo random number sequence from key information; a second pseudo random number generation means to generate a second pseudo random number sequence based on clock control performed according to the first pseudo random number sequence; and, a keystream generation means to generate a keystream by applying a nonlinear function calculation to the second pseudo random number sequence.

Growing community of inventors

Saitama, Japan

Shinsaku Kiyomoto