摘要:
A computer system that makes it difficult to analyze the content of a calculation. A power operation unit (262) performs the following operations using the input data “a” and “b”: ga=ga mod n, gb=gb mod n. Next, a multiplication unit (264) performs the following calculation using ga and gb: gab=ga×gb mod n. Next, a discrete logarithm calculation unit (266) calculates ci mod pi−1 to satisfy gab=gci mod pi (i=1, 2, 3, . . . ,k). Next, a CRT unit (267) calculates “c” to satisfy ci=c mod pi−1 (i=1, 2, 3, . . . ,k) using the Chinese remainder theorem CRT.
摘要:
The present invention offers a prime calculating apparatus for achieving prime calculation where producing identical primes is avoided by simple management techniques. The prime calculating apparatus stores a known prime q and management information unique in the use range of primes. The prime calculating apparatus reads the management information; generates random information R based on the read management information; reads prime q; calculates prime candidate N, according to N=2×random information R×prime q+1, using the read prime q and generated random information R; tests whether the calculated prime candidate N is a prime; and outputs the calculated prime candidate N as a prime when the primality of the calculated prime candidate N is determined. Herewith, the prime calculating apparatus is able to calculate prime candidates from unique management information while avoiding producing identical primes.
摘要:
The present invention is a content distribution system for distributing contents. The content distribution system (1) includes a key issuing center (11), a server (12), eight output apparatuses (13a) to (13h), and a communication path (10) that connects them to each other. Here, a pair of the key issuing center (11) and each of the output apparatuses (13a) to (13h) is previously given an individual key shared between them. For example, the key issuing center (11) shares an individual key IKa with the output apparatus (13a), an individual key IKb with the output apparatus (13b), and an individual key IKh with the output apparatus (13h).
摘要:
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.
摘要:
In scalar multiplication method using a Montgomery-type elliptic curve, a high-speed elliptic curve calculation device effectively uses a table that stores coordinates of certain scalar multiple points like points multiplied by exponentiation of two to a certain point G and so forth. The elliptic curve calculation device receives an arbitrary integer k of n bits and outputs scalar-multiplied points against a point G on a Montgomery-type elliptic curve E on a finite field F that is given in advance. The elliptic curve calculation device includes a calculation procedure generation unit that generates a calculation procedure that addition on the elliptic curve E with either of G, 2 *G, 22*G., . . . , 2n−1*G as the first addition element is repeated and a scalar multiplication unit that calculates the scalar-multiplied points k*G by repeating addition on the elliptic curve E, referring to a table memorizing unit that stores values (coordinates) of exponentiation of two against the point G and complying with the generated calculation procedure.
摘要:
A signature generation apparatus and a signature verification apparatus which can prevent the occurrence of norm zero vector forgery attack. The signature generation apparatus (110) includes a signature generation unit (114) which generates signature data (S) for a message (m) using a private key stored in a private key storage unit (112), and converts the format of the signature data (S) so that the first sub-element of the N sub-elements in the signature data (S) indicates 0 without changing the norm of the signature data (S). The signature verification apparatus (120) includes a signature verification unit (124) which judges whether or not the first sub-element of the N sub-elements included in the signature data (S) indicates 0, and determines the signature data (S) as unauthorized data when judging that it is not 0.
摘要:
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.
摘要:
A signature generation apparatus is capable of making a value used in signature generation processing difficult to analyze. In the signature generation apparatus, a random number generation module generates a len-bit random number u, a selection module converts the generated random number u into a bit expression, and acquires element pairs corresponding to the bit values from a table memory unit. A random element generation module applies a basic operation of a first group G and a second group to all acquired element pairs, and calculates an element Pk on the first group G and an element Pak on the second group Ga. The signature generation apparatus generates a digital signature S for a message m with use of a transformation module, a main operation module, an inverse transformation module, a multiplication module, a division module, and a signature data generation module.
摘要:
A content delivery system, enabling a ciphertext to be reduced in size when using the ElGamal cipher, includes a content delivery device performing elliptic curve encryption on a content key, generating an encrypted content key that includes an x coordinate of an elliptic curve point obtained by the elliptic curve encryption, and outputting the encrypted content key. Further, the content delivery system includes content reception device receiving the encrypted content key, calculating a y coordinate of the elliptic curve point using the x coordinate included in the encrypted content key, and performing elliptic curve decryption using the elliptic curve point and other information included in the encrypted content key, to generate a decrypted content key.
摘要:
A prime calculating apparatus calculating a prime and determining whether the prime has been duly generated. The prime calculating apparatus (i) generates a random number, (ii) calculates a multiplication value R by multiplying a management identifier by the random number, and (iii) calculates a prime candidate N, according to N=2×(multiplication value R+w)×prime q+1, with respect to w satisfying an equation of 2×w×prime q+1=verification value (mod management information). Then, the prime calculating apparatus judges whether the calculated prime candidate N is a prime, and outputs the calculated prime candidate N as a prime when determining that it is a prime.