Abstract: An optical imaging system includes: a first lens group including a plurality of lenses; a second lens group including a plurality of lenses; a first reflecting member disposed on an object side of the first lens group; and a plurality of second reflecting members arranged between the second lens group and an image sensor. One or both of the first lens group and the second lens group is movable along an optical axis, an interval along the optical axis between the first lens group and the second lens group is varied between a first interval and a second interval smaller than the first interval, and as at least one of the first lens group and the second lens group is moved, one or more of the second reflecting members are moved.

Abstract: An optical imaging system includes: a first lens group including a plurality of lenses; a second lens group including a plurality of lenses; a first reflecting member disposed on an object side of the first lens group; and a plurality of second reflecting members arranged between the second lens group and an image sensor. One or both of the first lens group and the second lens group is movable along an optical axis, an interval along the optical axis between the first lens group and the second lens group is varied between a first interval and a second interval smaller than the first interval, and as at least one of the first lens group and the second lens group is moved, one or more of the second reflecting members are moved.

Abstract: A semiconductor device and an electronic system including the same are disclosed. The semiconductor device may include a substrate including a cell array region and a connection region, the cell array region comprising a center region and an outer region; an electrode structure including electrodes and pads; vertical structures on the cell array region and penetrating the electrode structure; and a separation insulating pattern penetrating and dividing an upper electrode, which is one of the electrodes, into at least two portions arranged in a second direction crossing the first direction. The separation insulating pattern comprises a first portion and a second portion, the first portion is between at least some of the central vertical structures, and the second portion is spaced apart from the first portion such that, when viewed in the plan view, the second portion is between at least some of the peripheral vertical structure.

Abstract: A vertical semiconductor device includes a substrate with a first and second region. A conductive pattern on the first region extends in a first direction. The first region includes a cell region, a first dummy region and a second dummy region. The conductive pattern extends in a first direction. A pad is disposed on the second region, the pad contacts a side of the conductive pattern. A plurality of first dummy structures extends through the conductive pattern on the first dummy region. A plurality of second dummy structures extend through the conductive pattern on the second dummy region, the second dummy structures disposed in a plurality of columns that extend in a second direction perpendicular to the first direction. Widths of upper surfaces of the second dummy structures are different in each column, and the widths of upper surfaces of the second dummy structures increase toward the second region.

Abstract: A vertical semiconductor device includes a substrate with a first and second region. A conductive pattern on the first region extends in a first direction. The first region includes a cell region, a first dummy region and a second dummy region. The conductive pattern extends in a first direction. A pad is disposed on the second region, the pad contacts a side of the conductive pattern. A plurality of first dummy structures extends through the conductive pattern on the first dummy region. A plurality of second dummy structures extend through the conductive pattern on the second dummy region, the second dummy structures disposed in a plurality of columns that extend in a second direction perpendicular to the first direction. Widths of upper surfaces of the second dummy structures are different in each column, and the widths of upper surfaces of the second dummy structures increase toward the second region.

Abstract: A broadcast encryption method and a broadcast decryption method. The broadcast encryption method includes generating a message encryption key using a public key and a secret key generated by using a Strong Diffie-Hellman tuple; encrypting a message by the message encryption key; and generating a message header using a sum of a plurality of Strong Diffie-Hellman tuples corresponding to an authorized user group. Accordingly, a transmission amount and a storage amount can be reduced when a broadcast encryption message is transmitted.

Abstract: A method and system for updating time information of a digital rights management (DRM) includes a time server transmitting a time information message to a consumer electronics (CE) device, the CE device transmitting the time information message to a digital rights management DRM device when the CE device receives the time information message from the time server, and the DRM device updating a present time of the DRM device based on the time information message when the DRM device successfully performs authentication with respect to the time information message which has been transmitted from the CE device.

Abstract: An apparatus and method are provided for reducing time taken for generating a digital signature and generating the digital signature using a minimum number of operations using at least two secret keys. One secret key among at least two secret keys may be set from a value resulting from hashing a message to be transmitted. A number of times for hashing the secret key is determined, and a value resulting from hashing the determined secret key by the determined hashing number of times is set as the digital signature.

Abstract: A method and device for updating a group key are disclosed. The group key updating method comprises determining a start node for a key update on a binary tree, updating a node key of the start node for a key update, updating a node key of a parent node of a node corresponding to the updated node key using the updated node key, and repeatedly performing the updating of the node key of the parent node, and then updating a node key corresponding to a root node of the binary tree. With the disclosed method and device, it is possible to efficiently perform a group key update process.

Abstract: A method and apparatus for updating a group key of a group corresponding to a binary tree are provided. The method includes updating keys of leaf nodes that correspond to new members, in response to a join of at least two new members joining the group; determining whether both of two child nodes of a single ancestor node are updated when updating a key of the single ancestor node of the leaf nodes; establishing one of the two child nodes as an update use node when both the two child nodes are updated; and updating a key of the ancestor node using the updating node. Thus, the group key may be effectively updated with respect to multi-join.

Abstract: A key generation method for self-configuration is provided which includes selecting existing nodes as many as a predefined reference number t from nodes which configure a network; transmitting a partial key request message to the selected existing nodes; and generating a node key based on randomized partial keys received in response to the partial key request. Accordingly, when a new node intends to join the network, the existing nodes forming the network can allocate a node key to the new node by themselves. Also, whether the node key of the new node is compromised or not can be verified using the error-checking witness.

Abstract: A method of protecting a broadcast frame, the method comprising broadcasting a beacon and a maintenance beacon frame (MBF) from an access point (AP) to a plurality of terminals during a maintenance beacon waiting period (MBWP); and broadcasting broadcast management frames (BMFs) from the AP to the plurality of terminals during a broadcast management frame waiting period (BMFWP), wherein the MBF comprises a BMFs message integrity code (MIC) field including a BMFs MIC calculated from concatenated BMFs to be sent in a current beacon interval.

Abstract: A group key update method and a group key update apparatus for updating a key of members in a group are provided. The group key update method includes selecting a sub-root node among nodes on the binary tree; performing a node change with respect to the group according to a type of the sub-root node, and generating a changed binary tree; and performing a node key update with respect to the changed binary tree.

Abstract: Provided is an apparatus and a method of restricting an access to an application module of a mobile wireless device. The apparatus for restricting an access to an application module of a mobile wireless device according to an exemplary embodiment of the present invention includes an access restriction unit for receiving a request for an access to an application module from a basic module, and for restricting the access of the basic module to the application module when a restriction on the access is required. Further included is an access restriction determination unit for determining whether the restriction on the access of the basic module to the application module according to an access environment is required. Also included is an access environment determination unit for monitoring the access environment of the basic module to the application module and for providing the access restriction determination unit with a result of monitoring the access environment.

Abstract: An apparatus and method of detecting an intrusion code is provided. The apparatus for detecting an intrusion code includes: a set value input unit in which a set value differentiated for each group is input; an immune database generation unit which generates an immune database, based on the set value; and an intrusion code determination unit which determines whether data corresponds to an intrusion code, based on the generated immune database.

Abstract: Provided are a method of generating a node identifier including padding information and location information, in a tree structure, a computer-readable storage medium storing a program for executing a method of generating a node identifier in a tree structure, and a terminal apparatus using the tree structure. The location information is generated by using branch identifiers, each of the branch identifiers being allocated for each branch from a root node to a target node. The padding information is generated by a padding code, which includes information about a group of the target node, and depth information, which includes information about a level of the target node in the tree structure.

Abstract: A method for generating, operating, and using a sparse w-NAF key for encryption is disclosed. The method for generating a key comprises generating a string of a number of coefficients, in which at most one coefficient, excluding 0, among a consecutive w number of coefficients, corresponds to a positive odd integer equal to or less than 2w (w being a natural number equal to or more than 2); and outputting the generated string as a key. Accordingly, an encryption is executed through an exponential operation or scalar multiplication using a sparse w-NAF key having the scarce coefficients, excluding 0, such that an encryption pace is improved.

Abstract: A distributed Rivest Shamir Adleman (RSA) signature generation method in an ad-hoc network and a signature generation node are provided, including steps for distributing key information to a plurality of nodes using an RSA parameter and a maximum distance separable (MDS) code, in a dealer node, generating a partial signature using the key information and transmitting the generated partial signature to a signature generation node, in the plurality of nodes, and generating an RSA signature using the partial signature, in the signature generation node, wherein the RSA signature is generated using the partial signature, received from a fewer number of nodes than the entire plurality of nodes.

Abstract: A public key generation method in Elliptic Curve Cryptography (ECC), and a public key generation system performing the method are provided. The public key generation method includes reducing a sequence length of the signed ternary ?-adic representation of the private key ‘k’ using properties of an elliptic curve, representing a reduced secret key ‘k’ in a signed ternary ?-adic representation; and computing a public key kP by multiplying the ?-adic representation of the private key ‘k’ whose sequence length is reduced on point P on the elliptic curve.

Abstract: Disclosed are a method and apparatus capable of reducing the number of computations required to generate a digital signature by a digital signature generator. A digital signature generator generates a code word for a received message by a function F for generating a code word having a set weight value and generates a digital signature based on the generated code word and an inverse of a public parity check matrix H, the parity check matrix H is one way function. A digital signature receiver converts the received message using the function F for generating a code word, and multiplies a public parity check matrix H by a received digital signal, the public parity check matrix H is a one way function, and comparing the converted value with the multiplication result.