| Patent application number | Description | Published |
|---|
| 20080256362 | Method and apparatus for digital signature authentication, and computer product - An apparatus for digital signature authentication includes a dividing unit that divides streaming data into plural pieces of partial data in a predetermined unit; a first creating unit that creates a hash value string including plural hash values corresponding to the pieces of partial data; a second creating unit that creates a first binary tree using the hash value string; and a third creating unit that creates a digital signature of a signer using a root value of the first binary tree. | 10-16-2008 |
| 20090003598 | ENCRYPTING APPARATUS FOR COMMON KEY CIPHER - The first route selection device re-arrays a plurality of extended key mask values at random according to the value of a random number generated by a random number generation device. An extended key operation device generates an exclusive logical OR of a plurality of the re-arrayed extended key mask values, a data string representing extended key and an input data string. The second route selection device re-arrays the data string of the exclusive logical OR by performing a re-array conversely with the first route selection device according to the value of the random number. A non-linear conversion device applies non-linear conversion to the re-arrayed data string and outputs a data string masked by a plurality of non-linear conversion mask values. The third route selection device re-arrays the masked data string by performing the same re-array as the first route selection device according to the value of the random number. | 01-01-2009 |
| 20090013379 | METHODS AND APPARATUS FOR VERIFYING ELECTRONIC MAIL - A computer extracts the header information from an electronic mail, including an originality guarantee. The computer generates a header characterization for the header information subject to originality guarantee, and extracts message body information from the electronic mail and generates a body characterization for the message body information as well. The generated characterization set applies the header characterization and the body characterization, combined. The verification information is added to the generated characterization set for applying a signature, and characterization set is linked to electronic mail. | 01-08-2009 |
| 20090193256 | ELECTRONIC SIGNATURE METHOD, APPARATUS, AND RECORDING MEDIUM HAVING ELECTRONIC SIGNATURE PROGRAM RECORDED THEREON - A computer divides a target electronic document into a plurality of document segments. Then, the computer generates a signature (s, t) that includes a set of two values having a signature value s forming a signature on the electronic document and a deletion signature value t used for deletion, the signature value s which serves as a body of the signature being formed by a superposition of signature information on the individual document segments. Then, in a case where one of the plurality of document segments obtained by the division is to be extracted, the computer superimposes deletion information of a document segment to be deleted on the deletion signature value t to generate a new signature value t′, and produces an updated signature (s, t′). | 07-30-2009 |
| 20090205029 | MANAGEMENT APPARATUS - A management apparatus comprising memory to store owner information, dependence relationship information, and authorized user information are associated with file information identifying the secret file, an authorized user determination unit to determine whether a source user of the browse request is registered as the authorized user of the browse request file, a dependent file specifying unit to specify a dependent file having a dependence relationship with the browse request file by referring to the dependence relationship information when the source user is authorized; and a browse permission response transmitting unit to transmit the browse permission response to the source user based on whether or not the source user is registered as the authorized user of the dependent file by referring to the authorized user information. | 08-13-2009 |
| 20090210715 | Document verification apparatus, document verification method, and computer product - In verifying a digital document, an input of a digital document is received and the digital document is divided into arbitrary constituent parts. A normal random number or a pseudo random number is assigned to each of the constituent parts according to the order in which the constituent parts appear in the digital document. Thus, verification of the authenticity of a digital document is enabled even when an alteration, such as a change of the order of the partial documents or a copy thereof, has been made to the digital document. | 08-20-2009 |
| 20090265558 | DOCUMENT VERIFYING APPARATUS, DOCUMENT VERIFYING METHOD, AND COMPUTER PRODUCT - A computer-readable recording medium stores therein a document verifying program. The document verifying program causes a computer to execute receiving input of an electronic document; dividing the electronic document received into arbitrary components; calculating a hash value for each of the components; correlating, for each component, the hash value calculated for the component and a random number allocated to the component according to an appearance position of the component in the electronic document; creating for each component and based on the hash value and the random number correlated for the component at the correlating, a first digital signature and a second digital signature that are different from each other; and appending to each component, the first digital signature and the second digital signature created for the component at the creating. | 10-22-2009 |
| 20090290189 | Electronic document managing apparatus - An integrator acquires an electronic document and revised documents revised by different revisers (administrative department, accounting department) in parallel, and makes reference to the electronic document to judge whether each partial document is not disclosed in each revised document with respect to each sub-document in the electronic document. When each sub-document is not disclosed in at least one of the revised documents, whether each sub-document is to be disclosed is determined in regard to each sub-document based on a policy P that specifies disclosure/nondisclosure of each sub-document divided from the electronic document, and a revised document obtained by integrating the revised documents is created based on a determination result. | 11-26-2009 |
| 20100005306 | STORAGE MEDIA STORING ELECTRONIC DOCUMENT MANAGEMENT PROGRAM, ELECTRONIC DOCUMENT MANAGEMENT APPARATUS, AND METHOD TO MANAGE ELECTRONIC DOCUMENT - An electronic document management apparatus acquires an electronic document comprised of a plurality of components for each of which a first digital signature and a second digital signature are uniquely specified. The electronic document is linked to an aggregate digital signature which aggregates the first digital signatures. After that the apparatus accepts designation of a component to be “hiding prohibited” within the electronic document. Whether or not the component designated to be “hiding prohibited” is at that time in a state of “hiding allowed and deletion allowed” is judged. When the judgment reveals that the state is “hiding allowed and deletion allowed”, the second digital signature specified for the component designated to be “hiding prohibited” is deleted. Then the state of the component subject to be “hiding prohibited” is changed from “hiding allowed and deletion allowed” to “hiding prohibited and deletion allowed”. | 01-07-2010 |
| 20100014668 | Image data verification program recorded on a recording medium, image data verification method, and image data verification system - An image data verification system for verifying image data using a computer and method are provided. The method includes registering image data of an original and extracting information regarding a part of information forming the original image data. The method also includes generating a feature value of the partial information and generating signature information. | 01-21-2010 |
| 20100023571 | Modular multiplication calculation apparatus used for Montgomery method - REDC (A*B) is calculated for the values A and B by using a Montgomery's algorithm REDC. The part related to the A*B is performed by the three-input two-output product-sum calculation circuit. One digit a | 01-28-2010 |
| 20100031055 | EMBEDDED DEVICE HAVING COUNTERMEASURE FUNCTION AGAINST FAULT ATTACK - A cryptographic processing device, comprising: a storage unit; initial setting unit for setting a value to be stored in the storage unit; Montgomery modular multiplication operation unit for performing a Montgomery modular multiplication operation plural times for a value set by the initial setting unit; and fault attack detection unit for determining whether or not a fault attack occurred for each of at least some parts of the Montgomery modular multiplication operations performed plural times. | 02-04-2010 |
| 20100169653 | APPARATUS, METHOD, AND PROGRAM FOR DIGITAL SIGNATURE - A digital signature method to generate a signature for an electronic document, the method including: initializing a signature t of each of the document segments of electronic document and twice raising the signature t to the power of a hash value of each of the document segments and digitally signing the raised signature to produce a signature s serving as the signature of the electronic document; and revising a document segment; wherein, in the revising, to delete a document segment, the signature t is raised twice to the power of the hash value of the document segment unless the document segment is sanitization prohibited, or the signature t is raised to the power of the hash value of the document if the document segment is sanitization prohibited, and the document segment is deleted; to sanitize a document segment, the document segment is replaced with the hash value thereof. | 07-01-2010 |
| 20100232601 | ELLIPTIC CURVE ARITHMETIC PROCESSING UNIT AND ELLIPTIC CURVE ARITHMETIC PROCESSING PROGRAM AND METHOD - An apparatus for executing cryptographic calculation on the basis of an elliptic point on an elliptic curve includes: a memory for storing a first value including a plurality of digits; and a processor for executing a process including: obtaining a second value representing a point on the elliptic curve; calculating output values by using a predetermined equation, each digit of the first value, and the second value; determining whether at least one of the second value and the output values indicates a point of infinity; terminating the calculation when at least one of the second value and the output values indicates the point at infinity; and completing calculation when both the second value and the output values do not indicate the point at infinity, so as to obtain a result of the cryptographic calculation. | 09-16-2010 |
| 20110007894 | CRYPTOGRAPHIC PROCESSING METHOD, COMPUTER READABLE STORAGE MEDIUM, AND CRYPTOGRAPHIC PROCESSING DEVICE - stores, in | 01-13-2011 |
| 20110013769 | ENCRYPTION APPARATUS HAVING COMMON KEY ENCRYPTION FUNCTION AND EMBEDDED APPARATUS - A common key block encryption apparatus for performing a nonlinear transformation with a multiplication executed in a binary field or a composite field includes a computing unit to execute a computation other than the nonlinear transformation with fixed value masked input data obtained by XORing input data with a fixed mask value, an XOR operation circuit to transform all input data into fixed value masked input data by XORing the input data with a fixed mask value and to transform the data into random value masked input data by XORing the input data with a random mask value in the multiplication, a multiplier to execute a multiplication based on the random value masked input data output from the XOR operation circuit, and a random value mask-to-fixed mask value transformation circuit to again transform the random value masked output data into fixed value masked output data and to output the data. | 01-20-2011 |
| 20110072278 | DATA PROCESSING APPARATUS AND DIGITAL SIGNATURE METHOD - A data processing apparatus includes, an input unit to accept information on one or more deletion-target data blocks specified from a plurality of data blocks, a hash generating unit to calculate a hash value of each of the plurality of data blocks, an auxiliary data generating unit to calculate auxiliary data β=g | 03-24-2011 |
| 20110078458 | CONTENTS PROCESSING DEVICE AND CONTENTS PARTIAL INTEGRITY ASSURANCE METHOD - A contents processing device includes a management data storage unit to store an updater identifier and a private key, an accepting unit to accept a content which is divided into a plurality of blocks, an updating type indicating a type of an updating as to the content, an updated block to be updated of the content, and an updated position, an inserting unit to generate an updated content by inserting the updating block into the updated position of the content, a first hash value calculating unit to calculate a hash value as to the updated block, a signature unit to read out the updater identifier and the private key from the management data storage unit to generate a digital signature using the private key as to updating record information including the updater identifier, the updated position, the hash value as to the updated block, and the updating type. | 03-31-2011 |
| 20110078459 | SIGNATURE GENERATING DEVICE AND METHOD, SIGNATURE VERIFYING DEVICE AND METHOD, AND COMPUTER PRODUCT - A signature generating device includes a receiving unit that receives a sequence of data; a summary data generating unit that generates summary data of the data upon reception of each of the data by the receiving unit; an obtaining unit that obtains, when the number of data included in a sequence of the generated summary data reaches a given number, the sequence of the summary data as a block; a setting unit that sets, as a signature subject, a current block constituted by the sequence of the summary data, and the summary data selected from at least one block contiguous to the current block; a digital signature generating unit that generates a digital signature concerning data summarized for the current block; and a sending unit that sends the generated digital signature, the signature subject associated with the digital signature, and the data summarized for the current block. | 03-31-2011 |
