Abstract: A key setting method executed by a node within communication ranges of multiple ad-hoc networks, includes receiving encrypted packets encrypted by respective keys specific to gateways and broadcasted from the gateways in the ad-hoc networks; detecting connection with a mobile terminal communicable with a server retaining the keys specific to the gateways in each ad-hoc network among the ad-hoc networks; transmitting to the server when connection with the mobile terminal is detected, the encrypted packets via the mobile terminal; receiving from the server via the mobile terminal, the keys that are specific to the gateways in the ad-hoc networks and that are for decrypting each encrypted packet among the encrypted packets; and setting each of the received keys as a key to encrypt data that is to be encrypted in the node and decrypt data that is to be decrypted in the node.

Abstract: An authentication method executed by a computer includes: receiving input data which is a target of authentication; specifying registration data, from among a plurality of registration data stored in a storage device, having a second feature value within a threshold value relative to a first feature value of the input data, the first feature value representing a distance between the input data and a reference, the second feature value representing another distance between the registration data and the reference, and the threshold value being used when a determination as to whether the authentication has been successfully performed; and executing a process of comparing the registration data with the input data.

Abstract: A communication device includes a memory and a processor coupled to the memory and configured to, when a first vibration is detected in the communication device, set a certain state that protects information stored in the memory, and cancel the certain state based on receiving from another communication device a notification indicating that the other communication device detected a second vibration.

Abstract: An authentication device includes: a memory; and a processor coupled to the memory and configured to: when a registration request including authentication information to be used during authentication is received from a terminal device, generate registration information using the authentication information and key information and store the registration information in the memory, and when an authentication request including input information to be handled as the target of the authentication is received from the terminal device, generate a result of the authentication based on the input information, the registration information, and the key information, and transmit the result of the authentication to the terminal device.

Abstract: A network system includes: a plurality of node devices including a first node device and a second node device; and a verification node device that has a higher processing capacity than the plurality of node devices. The verification node device transmits a first packet including an identifier indicating the verification node device. The first node device receives a second packet from another node device out of the plurality of node devices, and determines, based on a destination of the second packet, reception of a packet from the second node device, and reception of the first packet, a transmission destination of a third packet that corresponds to reception of the second packet, from among the second node device and the verification node device. And, the verification node device verifies the third packet in a case of receiving the third packet.

Abstract: A node device which is provided in a network and for transmitting a packet including a first header portion, a second header portion, a payload data portion, the node device includes: a memory and a processor coupled to the memory. The processor is configured to: calculate a first value that is a first logical relationship for payload data set in the payload data portion and first header information including a transmission destination address set in the first header portion, and transmit a packet including the payload data, the first header information, second header information including a final transmission destination address set in the second header portion, the first value and a second value that is a second logical relationship to the payload data and the second header information to outside of the node device.

Abstract: A node in an ad-hoc network includes a memory unit storing a concatenated counter value including an erasure counter value and a transmission counter value for the node; and a processor configured to: add one to the transmission counter value, when the node transmits data to another node in the ad-hoc network; transmit to the other node, the data and the updated concatenated counter value; detect erasure of the concatenated counter value in the memory unit; distribute in the ad-hoc network and upon detecting the erasure, an acquisition request for the erasure counter value; receive the erasure counter value consequent to the acquisition request; generate the concatenated counter value to include the received erasure counter value plus one and the transmission counter value after the erasure and indicating the number of transmissions as zero due to the erasure; and archive to the memory unit, the generated concatenated counter value.

Abstract: A node device includes: a processor configured to: receive a first packet that is transferred from a source to a destination via at least one node device including the node device, the first packet including a counter value regarding a number of transfers of the first packet, and first coding information according to a first key information and contents of the first packet, determine whether to conduct a verifying process on the first packet based on the counter value, verify the first coding information is same as a second coding information, the second coding information being generated according to the contents of the first packet and a second key information stored in the memory, change the counter value in the first packet to an initial value, and transmit the first packet including a changed counter value to the destination or any one of the plurality of node devices.

Abstract: An information processing apparatus includes a processor configured to identify a data length that is longer than a data length of plain text data and that is a multiple of a predetermined block length; calculate a data length difference of the data length of the plain text and the data length; generate a first code that indicates the calculated data length difference; generate a second code that is calculated from the plain text data and is of a data length that is within a remaining data length acquired by subtracting a data length of the generated first code from the data length difference; create padding that includes the generated second code, has the first code at an end, and is of a length equivalent to the data length difference; concatenate the created padding to an end of the plain text data to generate concatenated data; and output the concatenated data.

Abstract: A key setting method executed by a node transmitting and receiving a packet through multi-hop communication in an ad-hoc network among ad-hoc networks, includes receiving a packet encrypted using a key specific to a gateway and simultaneously reported from the gateway in the ad-hoc network; detecting a connection with a mobile terminal capable of communicating with a server retaining a key specific to a gateway in each ad-hoc network among the ad-hoc networks; transmitting to the server, via the mobile terminal and when a connection with the mobile terminal is detected, the encrypted packet received; receiving from the server and via the mobile terminal, a key specific to a gateway in the ad-hoc network and for decrypting the encrypted packet transmitted; and setting the received key specific to the gateway in the ad-hoc network as the key for encrypting the packet.

Abstract: A key setting method executed by a node transmitting and receiving data through multi-hop communication in an ad-hoc network among multiple ad-hoc networks, includes detecting connection with a mobile terminal communicating with a server connected to a gateway in each ad-hoc network among the ad-hoc networks; transmitting by simultaneously reporting to the ad-hoc network, an acquisition request for a key for encrypting the data when the connection with the mobile terminal is detected at the detecting; receiving from the server via the mobile terminal, a key specific to a gateway and transmitted from the gateway to the server consequent to transfer of the simultaneously reported acquisition request to the gateway in the ad-hoc network; and setting the key specific to the gateway received at the receiving as the key for encrypting the data.

Abstract: 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.

Abstract: A communication method executed by a node in an ad hoc network having multiple nodes, includes receiving from a neighboring node of the node in the ad hoc network, a first packet that includes a sender address of the neighboring node and a first packet transmission count of packet transmissions from the neighboring node; extracting the first packet transmission count from the first packet; receiving from the neighboring node and after reception of the first packet, a second packet that includes the sender address of the neighboring node and a second packet transmission count of packet transmissions from the neighboring node; extracting the second packet transmission count from the second packet; determining whether the second packet is an invalid packet, based on the first packet transmission count and the second packet transmission count; and discarding the second packet upon determining the second packet to be an invalid packet.

Abstract: A key setting method executed by a node within communication ranges of multiple ad-hoc networks, includes receiving encrypted packets encrypted by respective keys specific to gateways and broadcasted from the gateways in the ad-hoc networks; detecting connection with a mobile terminal communicable with a server retaining the keys specific to the gateways in each ad-hoc network among the ad-hoc networks; transmitting to the server when connection with the mobile terminal is detected, the encrypted packets via the mobile terminal; receiving from the server via the mobile terminal, the keys that are specific to the gateways in the ad-hoc networks and that are for decrypting each encrypted packet among the encrypted packets; and setting each of the received keys as a key to encrypt data that is to be encrypted in the node and decrypt data that is to be decrypted in the node.

Abstract: 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 ?=gH1(mod N) of a signer based on predetermined values g and N and a product H1 of the hash values of one or more deletion-target data blocks, a digital signature generating unit to calculate intermediate data ?=gH2(mod N) based on the predetermined values g and N and a product H2 of the hash values of one or more remaining data blocks to generate a digital signature for a combination of the intermediate data ? and position data of one or more deletion-target data blocks with a signing key of a modifier.

Abstract: A method for generating a digital signature with respect to an electronic document, the method including: inputting a target electronic document and a corresponding digital signature ?; dividing the target electronic document into a plurality of partial documents mi; and when a revision of the partial documents is to be performed, in a case where deletion of the one partial document is to be performed, when sanitization is not prohibited, exponentiating the digital signature ? twice with a hash value Gi, when sanitization is prohibited, exponentiating ? with the Gi; in a case where sanitization is to be performed, replacing a partial document by Gi; in a case where deletion is to be prohibited, exponentiating ? with a hash value Hi; in a case where the sanitization is to be prohibited, exponentiating ? with Gi; and updating ?.

Abstract: 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.

Abstract: 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?).

Abstract: A communication device includes a data storage unit, a decryption unit, an encryption unit, and a judgment unit. The data storage unit stores a piece of encrypted data or a piece of decrypted data. The decryption unit decrypts each provided piece of encrypted data. The encryption unit encrypts each provided piece of decrypted data. The judgment unit issues an instruction to the encryption unit to read from the data storage unit first decrypted data obtained by the decryption unit decrypting first encrypted data with a cryptographic key, and to write back to the data storage unit second encrypted data obtained by the encryption unit encrypting the first decrypted data with the cryptographic key.

Abstract: A randomly selected point on an elliptic curve is set as the initial value of a variable and calculation including a random point value is performed in an algorithm for calculating arbitrary scalar multiple operation on an elliptic curve when scalar multiplication and addition on an elliptic curve are defined, then a calculation value obtained as a result of including a random point is subtracted from the calculation result, whereby an intended scalar multiple operation value on an elliptic curve is determined.