Abstract: A method of generating prevention and control data to verify validity of data to be transmitted, and an apparatus to perform the method, the method including generating the prevention and control data according to composing information of the data to be transmitted, and transmitting the prevention and control data along with the data to be transmitted to verify the validity of the data to be transmitted.

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 node device and method are described to prevent overflow of a pending interest table (PIT). When excessive request messages are received through a particular interface, the node device and method transmits a traffic control message to control a transmission interval of the request messages, which are transmitted to a corresponding interface.

Abstract: A node apparatus and method are described to prevent overflow of a pending interest table (PIT) in a name based network system. The node apparatus and method increases a number of PITs to correspond to a number of interface units so that the PITs match the interface units, respectively, and stores a request message flowing in per interface unit in the matching PITs. In addition, when a capacity used at each of the PITs exceeds a threshold, the node apparatus and method transmits a traffic control message for traffic control through respectively matching interface units to prevent overflow of the PITs.

Abstract: A content protection method includes generating content protection information regarding a content to be protected by a content producer, and generating a content name indicating a location of the content in content name based networks based on the content protection information. The content protection information may include at least one of marking information indicating whether the content is protected and policy information indicating a disclosure range of the content.

Abstract: A tag generation method for generating tags used in data packets in a broadcast encryption system is provided. The method includes detecting at least one revoked leaf node; setting a node identification (node ID) assigned to at least one node among nodes assigned node IDs at a layer 0 and to which the at least one revoked leaf node is subordinate, to a node path identification (NPID) of the at least one revoked leaf node at the layer 0; generating a tag list in the layer 0 by combining the NPID of each of the at least one revoked leaf nodes at the layer 0 in order of increment of node IDs of the corresponding at least one revoked leaf nodes; and generating a tag list in a lowest layer by repeatedly performing the setting and generation operation down to the lowest layer.

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: An apparatus for generating a key for access control of content in a distributed environment network is provided. The apparatus includes a first key distributor configured to generate first encrypted keys by encrypting a first key corresponding to a key for write authorization using each public key of members having write authorization among members included in an access control list including information of at least one user and distribute the access control list and information about access authorization and the first encrypted keys to the members having write authorization, and a second key distributor configured to generate second encrypted keys by encrypting a second key corresponding to a key for read authorization using the first key using each public key of members having read authorization among members included in the access control list and distribute the access control list and second encrypted keys to the members having read authorization.

Abstract: A combination-based broadcast encryption method includes: assigning by a server a base group of different combinations to each user; producing and sending secret information for each user by using as a base the base group allocated to each user; producing and sending an inverse-base parameter value through calculations with integers used to produce the base group and key value information of one or more privileged users; and deriving a group key by using the key value information of the privileged users, encrypting a session key by using the derived group key, and sending the encrypted session key to each user. Accordingly, each user is assigned a different base through a combination, thereby having security against collusion attacks.

Abstract: An apparatus and method for generating a key for a broadcast encryption. The apparatus includes a node secret generator for managing a user that receives broadcast data in a tree structure and for generating a unique node secret for each node in the tree structure. The apparatus also includes an instant key generator for temporarily generating an instant key used at all nodes in common in the tree structure, and a node key generator for generating a node key for each node by operating the node secret generated at the node secret generator and the instant key generated at the instant key generator. Thus, key update can be efficiently achieved.

Abstract: An apparatus and method for sharing and using content, and a comment on the content, via a distributed network are provided. A comment sharing apparatus for sharing a comment on content may generate the comment on the content, may set an access control policy for the comment, may generate a comment key based on the access control policy, may encrypt the comment using the comment key, and may share the encrypted comment via the distributed network. In response to the access control policy being accessible by only a content sharer sharing the content, the comment sharing apparatus may encrypt the comment key using a public key of the content sharer, and may share the encrypted comment key.

Abstract: A combination-based broadcast encryption method includes: assigning by a server a base group of different combinations to each user; producing and sending secret information for each user by using as a base the base group allocated to each user; producing and sending an inverse-base parameter value through calculations with integers used to produce the base group and key value information of one or more privileged users; and deriving a group key by using the key value information of the privileged users, encrypting a session key by using the derived group key, and sending the encrypted session key to each user. Accordingly, each user is assigned a different base through a combination, thereby having security against collusion attacks.

Abstract: Disclosed is an access control apparatus and method for giving access authority with respect to data. The access control apparatus may encrypt, using a Public Key (PK) of a terminal, a Node Key (NK) of a target layer in which the access authority is to be granted to the terminal, and produce an Access Control List (ACL) of the target layer based on the encrypted NK and ID information of the terminal. Also, the access control apparatus may produce a copy of the ACL based on the produced ACL, and store the produced copy of the ACL in a lower layer.

Abstract: Provided are methods and a validation system that includes a signature device and a verification device for verifying a content. The signature device may generate verification information for each segment of a divided content and may generate signature information to verify the integrity of each segment and whether a corresponding segment is a part of a content. When a segment is received, the verification device may verify integrity of the segment and whether the segment is a part of the content, based on the verification information and the signature value received from the signature device.

Abstract: An apparatus and method for generating a key for a broadcast encryption. The apparatus includes a node secret generator for managing a user that receives broadcast data in a tree structure and for generating a unique node secret for each node in the tree structure. The apparatus also includes an instant key generator for temporarily generating an instant key used at all nodes in common in the tree structure, and a node key generator for generating a node key for each node by operating the node secret generated at the node secret generator and the instant key generated at the instant key generator. Thus, key update can be efficiently achieved.

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 tag generation method for generating tags used in data packets in a broadcast encryption system is provided. The method includes detecting at least one revoked leaf node; setting a node identification (node ID) assigned to at least one node among nodes assigned node IDs at a layer 0 and to which the at least one revoked leaf node is subordinate, to a node path identification (NPID) of the at least one revoked leaf node at the layer 0; generating a tag list in the layer 0 by combining the NPID of each of the at least one revoked leaf nodes at the layer 0 in order of increment of node IDs of the corresponding at least one revoked leaf nodes; and generating a tag list in a lowest layer by repeatedly performing the setting and generation operation down to the lowest layer.

Abstract: A video watermarking apparatus and method are provided, including an information provider for providing spatial domain segmentation information of an image with respect to a compressed video, a grouping unit for grouping the compressed video, based on the spatial domain segmentation information, and generating a grouped spatial domain, an extraction domain selector for selecting an extraction domain for extracting a watermark from the grouped spatial domain, and a watermark extractor for extracting a watermark bit inserted in the extraction domain.

Abstract: An apparatus and method for video watermarking are provided. The apparatus and method include receiving a bit stream encoded by a video encoder by a spatial domain information analyzer and extracting information from a spatial domain of an image with respect to code words forming the bit stream, grouping the code words for each segmented domain by a domain classifier based on the information from the spatial domain, determining a sign of the each segmented domain by a domain sign determiner and inserting a watermark in the each segmented domain according to the sign determined by the domain sign determiner by a watermark bit inserter.