Patent application number | Description | Published |
20080232580 | SECRET SHARING APPARATUS, METHOD, AND PROGRAM - A secret sharing apparatus according to the present invention is based on a (k,n)-threshold scheme with a threshold of at least 4. The secret sharing apparatus generates a generator matrix (G) of GF( | 09-25-2008 |
20080304661 | CONTENT DISTRIBUTION/BROWSING SYSTEM, CONTENT DISTRIBUTION APPARATUS, CONTENT BROWSING APPARATUS AND PROGRAM - A content distribution/browsing system is disclosed. First to (m−1)th encrypted content items E(K | 12-11-2008 |
20090144543 | SECRET SHARING DEVICE, METHOD, AND PROGRAM - A secret sharing device of (k, n) threshold scheme creates a generator matrix G, first divided secret data, and random number data, calculates shared partial data based on the product of matrices with the random number data, the divided secret data, and the generator matrix G, and delivers the shared information formed by the shared partial data and the header information individually to the storage units. The secret sharing device calculates a recovery matrix and multiplies the shared information by the recovery matrix, hence to recover the secret information. | 06-04-2009 |
20090327706 | ACCOUNT MANAGEMENT SYSTEM, ROOT-ACCOUNT MANAGEMENT APPARATUS, DERIVED-ACCOUNT MANAGEMENT APPARATUS, AND PROGRAM - A root-account management apparatus generates an electronic signature based on a survival condition and a secret key when an authentication result of a user of a client apparatus is proper, and transmits derived-account credence element information including the survival condition, the electronic signature and a public key certificate to a derived-account management apparatus. The derived-account management apparatus creates derived-account information which becomes valid when the survival condition is satisfied so that the derived-account information includes both the derived-account credence element information which becomes invalid when a validity term of the public key certificate expires and a biometric information template of the user which is valid regardless of this validity term. Accordingly, even if an authentication element as a root (public key certificate) becomes invalid, a derived authentication element (biometric information template) can be prevented from becoming invalid. | 12-31-2009 |
20100180124 | VERIFICATION APPARATUS AND PROGRAM - According to one embodiment of the present invention, the first authentication context includes the template certificate indicative of the validity of a template and the first apparatus evaluation certificate indicative of the validity of the first apparatus evaluating information whilst the second authentication context includes the second apparatus evaluating certificate indicative of the validity of the second apparatus evaluating information. And the template certificate and the first and second evaluation certificates are verified when verifying the first and second authentication contexts. Thus, the validity of the template used for authentication or the apparatus evaluating information included in the authentication context can be verified. | 07-15-2010 |
20100191967 | CLIENT APPARATUS, SERVER APPARATUS, AND PROGRAM - A client apparatus receives a message including a random number from a server apparatus during the handshake of agreement process, creates a biometric negotiation message including the biometric authentication method information and sends the biometric negotiation message to the server apparatus. Then, the client apparatus executes a biometric authentication based on biometric authentication method information notified from the server apparatus and encrypts the random number based on the private key. In addition, the client apparatus generates an authenticator from a result of the biometric authentication, the biometric authentication method information, the encrypted random number, and the client certificate, and sends to the server apparatus an authentication context including these. The server apparatus verifies the authentication context and establishes a secure session in one handshake. | 07-29-2010 |
20110185413 | SYSTEM, APPARATUS, AND PROGRAM FOR BIOMETRIC AUTHENTICATION - A client apparatus transmits environmental information acquired from an environmental information acquisition device as well as a biometric authentication information matching result to a server apparatus. The server apparatus verifies the validity of the environmental information such as a luminance as well as the validity of the biometric authentication information matching result. If an environment is problematic, the server apparatus notifies the client apparatus that the environmental information is problematic. The client apparatus overcomes the problem of the environment such as the luminance based on the notification from the server apparatus and then retries a biometric authentication. The possibility of re-failure due to the environmental problem can be reduced during a retry of the biometric authentication. | 07-28-2011 |
20140161251 | KEY MANAGEMENT SYSTEM - According to one embodiment, a master key management device generates, by using a first secret key stored in a first storage unit and a third public key, a re-encryption key used to re-encrypt a second secret key which is stored in a second storage unit and which is encrypted with a first public key to the second secret key encrypted with the third public key. A key management server device receives the generated re-encryption key from the master key management device while the master key management device and the key management server device are connected to each other, and stores the received re-encryption key in a third storage unit. The master key management device and the key management server device are disconnected after the re-encryption key is stored in the third storage unit. | 06-12-2014 |
Patent application number | Description | Published |
20110308291 | TITANIUM SLAB FOR HOT ROLLING PRODUCED BY ELECTRON-BEAM MELTING FURNACE, PROCESS FOR PRODUCTION THEREOF, AND PROCESS FOR ROLLING TITANIUM SLAB FOR HOT ROLLING - A titanium slab is appropriate for hot rolling, is produced by electron beam melting furnace, has superior linearity so that it can be fed into a hot rolling machine without performing breaking down process or other subsequent correcting process after production, and has good structure having no cracks at the corner parts. A process for production thereof is also provided. The titanium slab is directly produced by a mold of an electron beam melting furnace, and has the deformation of not more than 5 mm for the thickness direction versus the longitudinal direction and deformation of not more than 2.5 mm for the width direction versus the longitudinal direction, both per a length of 1000 mm of the slab. The process for production of this titanium slab for hot rolling has a step of using an electron beam melting furnace in which its rectangular mold has mold walls of a long side and mold walls of a short side, and a step of pouring molten metal from one of the mold walls of a short side. Furthermore, a mold having chamfered parts at the corner parts can be used in the process. | 12-22-2011 |
20110311835 | TITANIUM SLAB FOR HOT ROLLING, AND METHOD OF PRODUCING AND METHOD OF ROLLING THE SAME - The present invention provides a titanium slab for hot rolling which can be fed into a general purpose hot-rolling mill for producing strip coil, without passage through a breakdown process such as blooming or a straightening process, and can further suppress surface defect occurrence of the hot-rolled strip coil, and a method of producing and a method of rolling the same, characterized in that in the cast titanium slab an angle θ formed by the crystal growth direction (solidification direction) from the surface layer toward the interior and a direction parallel to the slab casting direction (longitudinal direction) is 45 to 90°, and moreover, there is a surface layer structure of 10 mm or greater whose θ is 70 to 90°, and further characterized in that a crystal grain layer of 10 mm or greater is formed whose C-axis direction inclination of a titanium a phase is, as viewed from the side of the slab to be hot rolled, in the range of 35 to 90° from the normal direction of the surface to be hot rolled. The titanium slab concerned is produced using an electron beam melting furnace by casting at an extraction rate of 1.0 cm/min or greater. | 12-22-2011 |
20140050318 | RE-ENCRYPTION KEY GENERATOR, RE-ENCRYPTION APPARATUS, AND PROGRAM - A re-encryption key generator according to an embodiment generates a re-encryption key required to re-encrypt, without decrypting, ciphertext data obtained by encrypting plaintext data by means of a first public key of a first user device to obtain re-encrypted text data which can be decrypted by a second private key of a second user device. The first storage device stores a first private key corresponding to the first public key. The second storage device stores a second public key corresponding to the second private key. The re-encryption key generation device generates the re-encryption key based on the first private key, the second public key, and the first random number. | 02-20-2014 |
20140208117 | SERVER APPARATUS AND PROGRAM - A server apparatus according to an embodiment generates a random number on receiving from a user apparatus a notification showing that a re-encryption key should be updated, and calculates re-encryption key data on the basis of the re-encryption key stored and the random number generated. The server apparatus transmits the re-encryption key to the user apparatus and receives, from the user apparatus, the user private key not updated yet and re-encryption key updating data calculated from the re-encryption key data on the basis of the user private key updated. The server apparatus calculates the re-encryption key updated, on the basis of the re-encryption key updating data and the random number, and replaces the re-encryption key stored in the storage device with the updated re-encryption key. | 07-24-2014 |
20150043735 | RE-ENCRYPTED DATA VERIFICATION PROGRAM, RE-ENCRYPTION APPARATUS AND RE-ENCRYPTION SYSTEM - In a decryption apparatus according to an embodiment, a holding device pre-holds a verification formula. A determination device performs a calculation based on the verification formula read from the holding device by substituting, into the verification formula, the part of the re-encrypted data received from a re-encryption apparatus and the public key of a re-encryption key generation apparatus and the private key of the decryption apparatus, to determine whether or not the verification formula holds true. An output device outputs verification success when a result of the determination indicates that the verification formula holds true. | 02-12-2015 |