摘要:
A vibration diagnosis method for a rotary machine is disclosed. The presence or absence of a self-excited vibration is determined by checking if a rotating speed is in a rotating speed range which allows the occurrence of the self-excited vibration, if an amplitude of a frequency component corresponding to a first order critical speed is larger than a predetermined level, and if phases at characteristic points of vibration signals change among cycles.
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:
The data encryption apparatus with a data converting unit splits 256-bit input data into 32-bit data blocks A1, B1, A2, and B2. A first combining unit performs an exclusive OR operation on A1 and B1, and on A2 and B2. A first scramble unit branches A1, A2, and the results of the exclusive OR operations (C1 and C2) into three data blocks each, and for each set of three data blocks, shift-rotates two of the data blocks and combines the shifted data blocks with the remaining data block. A second combining unit performs an exclusive OR operation on D1 and E2, and on D2 and E1, which are the results of the processing performed by the first scramble unit. A block concatenating unit concatenates the results of the operations performed by the second combining unit. A second scramble unit branches the concatenated data into three data blocks, shift-rotates two of the data blocks and combines the two shifted data blocks with the remaining data block.
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.
摘要:
A content reproduction system that allow the user to rent or purchase any desired contents for reproduction without depending on a predetermined type of information of the user. The content reproduction system includes: a recording medium storing a license ticket including an encrypted master key; and a reproduction apparatus that receives from the user a request for a selected content and the information of the selected content, acquires distribution content information corresponding to the selected content, stores it in association with the license ticket into the recording medium. When reproducing the content, the reproduction apparatus generates a content using an encrypted content decryption key and an encrypted content that are contained in the distribution content information, and using a master decryption key information corresponding to the distribution content information, and reproduces the generated content.
摘要:
The cloning source of an authorized receiving device cannot be identified. A key distribution system 1 concerning the present invention includes: a communication channel 10; a key distribution center 11; a server 12; and receiving devices 13a to 13n. The key distribution center 11 distributes, to the server 12, the information necessary for distributing shared keys SK to the receiving devices 13a to 13n, and distributes the individual information group EMMG necessary for receiving the shared keys SK from the server 12. The server 12 generates the shared keys SK, generates the common information ECM based on the shared keys SK and the system secret variable group set SPGS, and distributes the common information ECM to the receiving devices 13a to 13n. The receiving devices 13a to 13n obtain the shared keys SK based on the individual information group EMMG and the common information ECM and outputs them to outside.
摘要:
A signature generation apparatus and a signature verification which can surely prevent occurrence of inappropriate signature verification error are providedA signature generation apparatus (110) includes a signature generation unit (114) which calculates a signature vector (s, t) for a message m using a private key, and generates signature data S indicating polynomials sl and sh that can specify the polynomial s and a polynomial th which is a quotient when the polynomial t is divided by q.
摘要:
An encryption device, a decrypting device, a secret key generation device, a copyright protection system and a cipher communication device including: a CRL memory unit memorizing a CRL, a device key ring memory unit memorizing a specific device key KD_A in every IC card used in a decrypting device, a content key memory unit memorizing a content key Kc, which is a secret key for decrypting content, and a hashing function processing unit calculating a hashing value of the CRL memorized in the CRL memory unit. The devices further including an Ex-OR unit carrying out an exclusive OR between the hashing value and the device key KD_A memorized in the device key ring memory unit, and an Enc unit encrypting the content key Kc memorized in the content key memory unit using an output value of an Ex-OR unit.
摘要:
To provide a system that can minimize a time delay caused by one device being unable to access a recording medium until access by another device ends, when transcoding is performed by distributed processing. A main device performs transcoding of each coded piece allocated to itself from among a plurality of coded pieces of a digital stream, and writing of a transcoding result onto the recording medium, in a pipeline. While the recording device is performing the transcoding and the writing, an auxiliary device transcodes each coded piece allocated to itself one by one. Having completed the transcoding of all coded pieces allocated to itself, the auxiliary device transmits its transcoding results to the recording device and has the recording device write the transcoding results onto the recording medium which is a copy destination.