Abstract: 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.

Abstract: A stream-cipher encrypting method includes first step of expanding an initial key in advance to generate an expanded key by a key expanding unit, a second step of inputting the generated expanded key and an initial value in the initialization processing by an initialization processing unit to carry out the initialization processing, a third step by a key-sequence generating unit of inputting a feedback value from a non-linear unit after the initialization processing is finished, parallelly processing non-linear processing, and maintaining and processing rearranging processing and a multiplication result, which is for obtaining the feedback value, as a data table to generate a key sequence by a non-linear function, and a fourth step of carrying out an exclusive-OR operation of the generated key sequence and a plaintext to generate an encrypted text by an encrypted-text generating unit.

Abstract: 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.

Abstract: 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.

Abstract: A broadcast receiving apparatus comprises a broadcast receiving unit (1, 4˜13) for receiving a digital broadcast; a communication unit (1˜3) for performing two-way communication through a network; an operation unit 15 for performing an acquisition operation of a key for decrypting an encrypted broadcast program received by the broadcast receiving unit; and an address generating unit 16 for 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.

Abstract: 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.

Abstract: 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 (np?1) divided pieces of secret information Kq (np is a prime number which is equal to or greater than a secret distribution number n). Furthermore, dummy secret information K0 is 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 K0, the divided piece of secret information Kq, and the random numbers R. The pieces of shares thus generated are concatenated so as to generate n shares Si, thereby providing a (k,n) threshold secret sharing scheme.

Abstract: 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.

Abstract: 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.

Abstract: In order to provide various service types to the users in a case of supplying the contents constituted from multiple resources via broadcast, the following apparatuses are provided. An encryption apparatus (100) encrypts the resources-to-be-encrypted of the contents, stores the encrypted resources in the packets and transmits the packets via broadcast. An encryption portion which encrypts each of contents constituted from multiple resources by applying a corresponding encryption key and generates and transmits packets that store encrypted data or non-encrypted data of the resources. A licensing apparatus (2) providing a license via communication network while the license includes both a license identifier which indicates a broadcast range in which the license is effective and the decryption key provided in correspondence with each of resources-to-be-encrypted.

Abstract: 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 modules 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.

Abstract: A broadcast receiving apparatus comprises a broadcast receiving unit (1, 4˜13) for receiving a digital broadcast; a communication unit (1˜3) for performing two-way communication through a network; an operation unit 15 for performing an acquisition operation of a key for decrypting an encrypted broadcast program received by the broadcast receiving unit; and an address generating unit 16 for 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.

Abstract: 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 (np?1) divided pieces of secret information Kq (np is a prime number which is equal to or greater than a secret distribution number n). Furthermore, dummy secret information K0 is generated. Moreover, random numbers R, which are pairwise independent are generated. Then, pieces of shares are created using exclusive-OR (XOR) operations based upon the dummy secret information K0, the divided piece of secret information Kq, and the random numbers R. The pieces of shares thus generated are concatenated so as to generate n shares Si, thereby providing a (k,n) threshold secret sharing scheme.

Abstract: 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.