摘要:
A content distribution system distributes contents. The content distribution system includes a key issuing center, a server, eight output apparatuses, and a communication path that connects them to each other. The key issuing center and each of the output apparatuses are previously given an individual key shared between them. For example, the key issuing center shares individual key IKa with an output apparatus, individual key IKb with an output apparatus, and individual key IKh with an output apparatus.
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:
Resistance against simple power analysis is maintained while a smaller table is used. An IC card 100 decrypts encrypted information using elliptic curve calculation for calculating a point k*C by multiplying a point C on the elliptic curve E with a coefficient k that is a positive integer less that a prime p. The calculation of the point k*C is performed by adding a multiplication result obtained by multiplying a digit position (window) value w of the acquired coefficient k with the point C in a position corresponding to the digit position, and is performed with respect to all digit positions. When a non-negative integer exists that fulfills a condition that the acquired digit value w can be divided by 2t and cannot be divided by 2t+1, the multiplication includes adding a point obtained by multiplying a point Q with w/2t.
摘要:
A signature generation apparatus capable of preventing transcript attack on signature data is provided. The signature generation apparatus performing a digital signature operation with the use of a signature key: stores the signature key; performs the digital signature operation on signature target data with the use of the signature key to generate signature data; counts the cumulative count of digital signature operations having been performed by the signature generation unit with the use of the signature key; judges whether the cumulative count has reached a predetermined count; and inhibits the use of the signature key in the digital signature operation from then onward in a case where the judgment unit determines that the cumulative count has reached the predetermined count.
摘要:
Processing load on an executing device for conducting playback is high during the playback of contents since the executing device performs verification of the contents validity in parallel with the contents playback, and therefore the executing device has to be equipped with a highly efficient processor. The present invention reduces the processing load involved in the verification by using, for the verification, only a predetermined number of encrypted units selected randomly from multiple encrypted units consisting encrypted contents recorded on the DVD. In addition, the present invention is capable of improving the accuracy of detecting unauthorized contents to some extent by randomly selecting a predetermined number of encrypted units every time the verification is performed.
摘要:
In an authentication system, a key registration apparatus receives input of an identifier unique to a second device, generates first key data from the identifier according to a predetermined key generation algorithm, and transmits the generated first key data to a first device, which receives and stores the first key data, and authenticates the second device with use of the first key data. The second device stores in advance second key data generated from the identifier according to the predetermined key generation algorithm, and is authenticated by the first device with use of the second key data. Accordingly, the first and second devices cannot be registered without using the key registration apparatus, thereby preventing communication with unregistered devices. This enables usage of content to be limited to individual usage in the home of a user, and can be realized even with devices that are not connected outside the home.
摘要:
Processing load on an executing device for conducting playback is high during the playback of contents since the executing device performs verification of the contents validity in parallel with the contents playback, and therefore the executing device has to be equipped with a highly efficient processor. The present invention reduces the processing load involved in the verification by using, for the verification, only a predetermined number of encrypted units selected randomly from multiple encrypted units constituting encrypted contents recorded on the DVD. In addition, the present invention is capable of improving the accuracy of detecting unauthorized contents to some extent by randomly selecting a predetermined number of encrypted units every time the verification is performed.
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).