Abstract: A method and apparatus for managing digital content are provided. The apparatus for managing digital content generated by applying digital rights management (DRM) includes: a content execution unit executing digital content; and a control unit confirming whether or not digital content is in a first period in which the digital content can be normally executed, and controlling the content execution unit so that, if the digital content is in the first period, the digital content can be executed normally, and if the digital content is in a second period which is not in the first period, the digital content can be executed in a manner which can be distinguished from that of execution in the first period. According to the apparatus and method, execution of digital content, which is close to expiration, can be controlled, thereby managing the expiration of the digital content for a user.

Abstract: A reproduction method capable of immediately revoking a leaked device key by dividing the device key into a first partial key and a second partial key is provided. The reproduction method includes the operations of receiving encrypted content to be reproduced, requesting a token for decrypting the received content from an external device containing a first partial key of a device via a network, receiving the requested token from the external device, and decrypting the received token by using a second partial key contained in the device, thereby preventing content encrypted and distributed before revocation of an illegally copied device from being reproduced, and minimizing damage due to key leakage.

Abstract: A mobile apparatus and method for displaying an Augmented Reality (AR) in the mobile apparatus. The mobile apparatus captures an image of a current environment of the mobile apparatus, displays the image, detects mapping information corresponding to the current environment from among mapping information stored in the mobile apparatus, maps a three-dimensional (3D) Graphical User Interface (GUI) of detected mapping information onto the displayed image, based on a relative location relationship between the detected mapping information, and adjusts a display status of the 3D GUI, while maintaining the relative location relationship between the detected mapping information.

Abstract: Provided are a method of tracing a device key in a user key management system using a hierarchical hash chain broadcast encryption scheme (HBES) algorithm, a user key management system for executing the method of tracing a device key, and a computer program for executing the method of tracing a device key. The method of tracing a device key of an illegal decoder in a user key management system for broadcast encryption includes: tracing a device key using a binary search; and revoking the traced device key. The technology according to the present invention can be applied to prevent exposure of the device keys to hacking. The present invention provides a method of tracing which can be applied to an HBES algorithm structure.

Abstract: A method and apparatus for updating data, the method including: receiving a forced update command to forcibly update at least one of a first digital rights management (DRM) module and a first device key stored in the device; receiving a DRM package including at least one of a second DRM module and a second device key based on the forced update command; and updating the at least one of the first DRM module and the first device key based on the received DRM package.

Abstract: A method and apparatus for protecting digital content in a digital rights management (DRM) system are provided. The method of importing a first content file into a second content file includes determining a usage rule of content included in the first content file based on information used to control remote access of the content included in the first content file; and generating the second content file that follows the determined usage rule.

Abstract: Provided are a method of tracing a device key in a user key management system using a hierarchical hash chain broadcast encryption scheme (HBES) algorithm, a user key management system for executing the method of tracing a device key, and a computer program for executing the method of tracing a device key. The method of tracing a device key of an illegal decoder in a user key management system for broadcast encryption includes: tracing a device key using a binary search; and revoking the traced device key. The technology according to the present invention can be applied to prevent exposure of the device keys to hacking. The present invention provides a method of tracing which can be applied to an HBES algorithm structure.

Abstract: Provided is a method of transmitting content keys to nodes arranged in a hierarchical structure which includes a plurality of node groups each including a predetermined number of the nodes. In this method, revoke information that includes identifiers of revoked node groups in the hierarchical structure, the total number of independent revoked nodes, and identifiers of the independent revoked nodes is generated. The revoked node groups are node groups consisting of only revoked nodes, and the independent revoked nodes are revoked nodes not belonging to any of the revoked node groups. Then, encrypted content keys are obtained by encrypting content keys using broadcast encryption, by using an encryption key set that has a form that cannot be generated using a decryption key set that the revoked nodes possess, and a set of encrypted content keys is generated. Thereafter, the revoke information and the set of the encrypted content keys are transmitted to all of the nodes arranged in the hierarchical structure.

Abstract: Provided are a method and apparatus for mutually authenticating devices in a group and reproducing content using public broadcast encryption. The method of authenticating a first device and a second device includes acquiring specific information of the second device from the second device, transmitting data, containing the acquired specific information of the second device and specific information of the first device, by encrypting the data using a broadcast public key of a group to which the second device belongs, and determining whether authentication of the first device succeeds by decrypting the encrypted data by using a private key of the second device. If authentication succeeds, receiving the specific information of the first device, which is encrypted by using a temporary common key by using the decrypted data, and authenticating the second device by decrypting the encrypted specific information of the first device by using the temporary common key.

Abstract: A reproduction method capable of immediately revoking a leaked device key by dividing the device key into a first partial key and a second partial key is provided. The reproduction method includes the operations of receiving encrypted content to be reproduced, requesting a token for decrypting the received content from an external device containing a first partial key of a device via a network, receiving the requested token from the external device, and decrypting the received token by using a second partial key contained in the device, thereby preventing content encrypted and distributed before revocation of an illegally copied device from being reproduced, and minimizing damage due to key leakage.

Abstract: Provided are a method and apparatus for generating separate rule data using a database management system (DBMS) based language in order to efficiently manage usage rules of content. The method of providing usage rule data of content included in a mobile storage medium connected to a content reproduction device, the method includes: generating first rule data that is a set of rules used to manage the usage rule data based on a data structure of a database management system (DBMS); and generating second rule data that is a set of rules used to access the usage rule data using the first rule data.

Abstract: A mutual authentication method using a mediation module and a system therefor are provided.

Abstract: A portable memory apparatus having a content protection function is provided. The portable memory apparatus includes a memory and a memory control unit. The memory includes a read-only memory area which stores content and is set to so that only read operations are allowed, a writable memory area which is set so that read and write operations are allowed, and a special memory area which stores information needed to operate the portable memory apparatus and is set so that only authenticated programs are allowed to read from and/or write to the special memory area. The memory control unit controls the read and write operations on each of the areas.

Abstract: Provided is a method of conditionally decrypting content. In the method, whether a content key for encrypting and/or decrypting content is revoked is determined, and encrypted content is selectively decrypted using the content key.

Abstract: A method of transmitting content between devices and a system therefor are provided. The method of transmitting encrypted content in a state in which the encrypted content and license information is stored and in which an external device is connected, includes: transmitting the license information corresponding to the encrypted content to the external device; transmitting the encrypted content to the external device, when receiving a request for transmitting the encrypted content from the external device; and updating the license information. Accordingly, content can be rapidly and stably transmitted between the devices. Also, it is possible to improve the accuracy and the security in the procedure of updating the license information.

Abstract: Provided are a method and a system for mutual authentication between mobile and host devices. The mobile device stores a first secret key and is connected to the host device. The method includes generating a second secret key using the first secret key and first data that is received from the host device and is encrypted using a predetermined method. The method further includes transmitting second data that is encrypted using a predetermined method, to the host device to induce generation of a media key; performing an operation on the second secret key and transmitting a generated operation value to the host device; and performing mutual authentication between the mobile device and the host device.

Abstract: A method and apparatus for managing digital content are provided. The apparatus for managing digital content generated by applying digital rights management (DRM) includes: a content execution unit executing digital content; and a control unit confirming whether or not digital content is in a first period in which the digital content can be normally executed, and controlling the content execution unit so that, if the digital content is in the first period, the digital content can be executed normally, and if the digital content is in a second period which is not in the first period, the digital content can be executed in a manner which can be distinguished from that of execution in the first period. According to the apparatus and method, execution of digital content, which is close to expiration, can be controlled, thereby managing the expiration of the digital content for a user.

Abstract: Provided are an apparatus and method for determining the integrity of content in at least one packet of a plurality of packets. A content using apparatus includes a receiver which receives a transport packet including content in at least one packet and a secret set, which includes an integrity check key generated for determining the integrity of the content, and extracts the secret set by processing the transport packet, a storage unit which stores the secret set, a controller which uses the secret set to determine whether each packet having the content maintains integrity, and a data processing unit which processes the at least one packet if the at least one packet is determined to be maintaining integrity. Accordingly, when content is transmitted, the integrity of the content can be checked using only a small amount of transmission data and a small amount of computation.

Abstract: A method of decoding/encoding a content file is provided. The method of decoding a content file includes dividing an encoded content file into a plurality of data blocks, grouping the plurality of data blocks into a plurality of groups, generating a group content key for each of the plurality of groups, generating a plurality of block keys for the data blocks in each of the plurality of groups from the group content key generated for each of the plurality of groups, and decoding the plurality of data blocks using the plurality of block keys.

Abstract: Provided is a contents decoding method using a digital rights management (DRM) card. The method of decoding contents received from a host device connected with a DRM card storing DRM software includes: receiving encrypted contents information from the host device and granting a contents decoding request; executing the DRM software corresponding to the contents information and decoding the received contents; and transmitting the decrypted contents to the host device, thereby using various pieces of contents regardless of a DRM system set in contents and easily upgrading DRM software to defend against hacking. Further, a host device does not require DRM software, which enables mass production and reduces manufacturing costs.