Abstract: A method and an apparatus for managing domains are provided. The method of managing one or more domains performed by a domain manager located in a home network includes determining whether to register a first device located in the home network to a domain, and providing data required to share content between the first device and a second device registered to the domain according to the determination. In the method and apparatus, content can be shared by connecting the devices with one another including a user, and the burden of content providers for management can be reduced.

Abstract: A method and apparatus for protecting digital content in a digital rights management (DRM) system are provided. The method includes: determining a usage rule for content included in a first content file based on usage constraint information included in the first content file; and generating a second content file complying with this usage rule. According to the method and apparatus, the security requirement of content creators and content providers can be satisfied and at the same time the requirement of content consumers for freer usage can be satisfied.

Abstract: A scrambling apparatus and method are provided for increasing randomness without damaging compression efficiency of total video data by selectively and randomly performing conversion when converting motion vector codes of compressed video data into other motion vector codes indicating other motion vector values, and more particularly, by performing conditional conversion only if a predetermined condition is satisfied when selective conversion of motion vector codes is performed. The scrambling apparatus includes a conversion motion vector code table generator generating a conversion motion vector code table comprising motion vector codes obtained by converting motion vector codes corresponding to motion vector values of input video data in a standard motion vector code table; and a conversion controller randomly determining whether a certain motion vector value is encoded using the conversion motion vector code table or the standard motion vector code table.

Abstract: A method and apparatus are provided for simply and securely limiting a number of times that contents can be accessed using a hash chain. The apparatus limiting a number of times contents are accessed by a user terminal includes a hash chain generator receiving information indicating selected contents by the user terminal and information indicating how many times (n) the user terminal has authority to access the selected contents and generating a hash chain including n hash values derived from a seed value, and a contents access manager deleting the hash values one by one from the hash chain whenever the user terminal accesses the selected contents such that the number of times the contents can be accessed by the user terminal is decreased by the number of deleted hash values.

Abstract: Provided are methods of generating and verifying an electronic signature of software data, wherein software data is split into a plurality of blocks, electronic signatures corresponding to each of the blocks are generated, and some of the electronic signatures are randomly selected for verification. Accordingly, a time required for verifying an electronic signature can be reduced while maintaining the advantages of an electronic signature system.

Abstract: Provided is a method of protecting a content consumer's privacy. The method includes classifying contents into content groups, encrypting the contents using different encryption keys, generating a plurality of decryption keys each of which can decrypt all contents in each of the content groups, and provides the generated decryption keys to authorized clients, wherein each client is provided with a different decryption key.

Abstract: A method of converting a license is provided. The method includes obtaining a domain policy from a domain to which content is to be transmitted, determining whether license information that is information for a content usage limitation and the domain policy coincide, and then based on the determination result, selectively converting a license.

Abstract: An AV stream processing system includes an AV stream input unit which receives an AV stream having an AV content information field including first copy control information, and an AV content field including second copy control information, a determination unit which extracts the first and second copy control information from the received AV stream and determines whether the first copy control information has been modified, and an AV stream decryption unit which processes the received AV stream according to predetermined criteria, when the first copy control information has been modified.

Abstract: A method and apparatus for performing authentication are provided. The method includes: receiving an authentication request signal for requesting authentication from an external device; determining whether authentication has been performed with the external device that has transmitted the authentication request signal; based on the determination, selectively outputting an indication representing that it is necessary to perform authentication with the external device; if the indication representing that it is necessary to perform authentication with the external device is output, receiving an authentication execution command for instructing the execution of authentication in response to the indication; and performing authentication with the external device according to the authentication execution command.

Abstract: A method and apparatus for preventing modulation of an executable program are provided. The method includes decoding a header of the executable program and generating information about a plurality of executable codes, grouping the plurality of executable codes into a first code group and a second code group with reference to the information about the plurality of executable codes, matching each of the plurality of executable codes included in the first code group with each of the plurality of executable codes included in the second code group, and encoding each of the corresponding executable codes included in the second code group using each hash value of the executable codes included in the first code group.

Abstract: Provided is a contents sharing method between a mobile terminal and a local server. The contents sharing method between a client terminal storing metadata and a server terminal storing the metadata, the method comprising requesting the server terminal for a contents share service; and receiving information on contents corresponding to matching metadata as a result of comparing the metadata stored in the, client terminal and the metadata stored in the server terminal, thereby sharing contents desired by the user without the user's intervention. Also, the user can communicate desired contents information with people in a bus, subway, library, etc., which forms a social network, and produces a contents flow between mobile terminals, thereby creating a new business model such as contents resale, promotion, etc.

Abstract: A method and apparatus for effectively managing a plurality of licenses are provided. The method includes selecting a value, which corresponds to license information, from a Hash mapping table; selecting a node corresponding to the license information from a tree structure corresponding to the value; and searching for a license by using license location information contained in the node. The apparatus includes a Hash function processor which computes a first value corresponding to the license information using a Hash function; a controller which selects a tree structure corresponding to the license information based on the first value computed by the Hash function processor; a tree structure manager which selects a node corresponding to the license information from the tree structure; and a storage unit which stores the license.

Abstract: Provided are a method and apparatus for acquiring data regarding a domain for the protection of digital content, and more particularly, a method and apparatus for acquiring domain information and domain-related data in which content received from an external source is converted into content that complies with a set of rules of a digital rights management (DRM) system and a license for the use of the result of the conversion is issued by receiving domain information including a domain key identifier from a domain information providing apparatus and receiving an updated domain key that is a valid domain key currently being used in a domain from a DRM object providing apparatus.

Abstract: A method and an apparatus for managing domains are provided. The method of managing one or more domains performed by a domain manager located in a home network includes determining whether to register a first device located in the home network to a domain, and providing data required to share content between the first device and a second device registered to the domain according to the determination. In the method and apparatus, content can be shared by connecting the devices with one another including a user, and the burden of content providers for management can be reduced.

Abstract: A method and an apparatus for transmitting content from a first device that joins a domain to a second device that does not join the domain are provided. If the second device which does not join the domain is adjacent to the first device which joins the domain, by encrypting a content key corresponding to the content to be transmitted to the second device which does not join the domain using a key of the second device which does not join the domain, and then transmitting the content and the encrypted content key to the second device which does not join the domain, the second device which does not join the domain can use the content having an access authority limitation, which can be used by only devices which join the domain.

Abstract: A method and apparatus for protecting digital content in a digital rights management (DRM) system are provided. The method includes: determining a usage bind of content based on usage constraint information of the content; and generating a license of the content for each usage bind. According to the method and apparatus, by generating the license of the content with respect to each usage bind, the content can be protected in a variety of ways with respect to the usage bind of the content, in addition to the conventional content protection by usage constraint information.

Abstract: A method and apparatus for protecting digital content in a digital rights management (DRM) system. The method of re-importing a second content file, which was imported from a first content file, as a third content file, includes determining whether to allow the re-importing of the second content file based on a difference between a current usage bind of the content determined in an import process and an original usage bind of the content and changing a usage bind of the content from the current usage bind to the original usage bind based on the result of determination. Therefore, when the usage bind of content, which had to be a domain bound, was inevitably determined to be a device bound due to a situation at the time of a content import process, the content can be freely used in the domain bound, which is the original usage bind of the content, according to usage constraints information (UCI) of the content.

Abstract: An apparatus and method for protecting digital content in a digital rights management (DRM) system. In the apparatus and method, usage rules for respective content parts included in a first content file are determined based on plural items of information in the first content file, and a second content file complying with the usage rules is generated. Accordingly, it is possible to allow a user to use only that part of the content included in an externally received content file, which the user has a right to use.

Abstract: A method and apparatus for protecting digital content in a digital rights management (DRM) system are provided. The method includes: determining a usage rule for content included in a first content file based on usage constraint information included in the first content file; and generating a second content file complying with this usage rule. According to the method and apparatus, the security requirement of content creators and content providers can be satisfied and at the same time the requirement of content consumers for freer usage can be satisfied.

Abstract: Provided are a method and apparatus for effectively fixing scrambled content. The method includes checking fixing information for a program map table (PMT) packet of packets constituting the content, the fixing information being used to fix a transformed part of the content; extracting location information of a next PMT packet containing fixing data for fixing the transformed part of the content from the fixing information of the PMT packet; and fixing the transformed part of the content by using the fixing data in the next PMT packet indicated by the extracted location information. Accordingly, it is possible to easily detect a location of the content, which stores the fixing information, thereby expediting fixing of the transformed content.