Abstract: A method and apparatus for managing digital content, which can detect the leakage of an encryption key when the encryption key used for encrypting the digital content is leaked or cracked. When the encrypted digital content is decrypted by an illegal device, a module linked with the encrypted digital content is automatically driven and a digital content managing apparatus is then notified that the encrypted digital content has been decrypted by the illegal device such that the digital content managing apparatus can change the encryption key. Thus, it is possible to prevent the digital content from being continuously leaked due to the use of the same encryption key for encrypting subsequent digital content.

Abstract: A method of backing up domain information relating to the construction of a domain is provided. In the method, the domain information is encrypted and the encrypted domain information is stored in a predetermined storage device in the domain the encrypted domain information to the predetermined storage device, thereby securely backing up the domain information without the help of an external network. Accordingly, even when the existing domain server malfunctions, a new domain server is capable of obtaining the domain information.

Abstract: A method of measuring round trip time (RTT) includes: chain-hashing at least one random number to create a plurality of hash values; (b) transmitting one of the created hash values to a device and starting to measure RTT of the device; and (c) receiving from the device a response to the transmitted hash value and ending the RTT measurement, thereby performing a more effective proximity check than a conventional proximity check requiring encryptions and decryptions of several tens of times through several thousands of times.

Abstract: Provided is a method for quantitative evaluation of mar- and scratch-induced surface damage on polymeric and coating materials. The method for quantitative evaluation of scratch-induced damage on polymeric and coating materials includes: preparing a test specimen of polymeric and coating materials; inducing a scratch damage on the surface of the test specimen; representing the scratch damage formed on the test specimen as corresponding color coordinates; and calculating a quantitated scratch damage index from a combination of a load applied to the surface of the test specimen and the color coordinates corresponding to the scratch damage.

Abstract: A method and apparatus for encrypting or decrypting digital content are provided. In the method, a binding range is selected from a plurality of binding ranges of content use based on license information of the content, and the content is encrypted based on the selected binding range so that the content can be used only within the selected binding range. Accordingly, it is possible to limit content use to a plurality of binding ranges of use of the content, using license information of the content.

Abstract: A home network system allowing a user to directly control joining or removing of member devices in a domain using a user interface and to effectively control a status change of the member devices of the domain and a management method therefor. The home network system includes: a master device, which forms a domain with more than one controlled device, transmits a predetermined domain key to the controlled devices included in the domain, generates a new domain key whenever a configuration of the domain is changed, and transmits the new domain key to the controlled devices remaining in the domain; and a control point, which provides a user interface allowing a user to directly change the configuration of the domain.

Abstract: A method of receiving a session key in a home network and a method of reproducing content using the same. The method of receiving a session key from a home server in a home network, includes: (a) whenever one of members of the home network changes, receiving and storing the session key and a session version indicating a session key generation sequence; (b) receiving a license necessary for reproducing predetermined content; and (c) determining a session key necessary for reproducing the predetermined content based on an encoding session version (ESV), which is a session version extracted from the license, and the stored session version. A home server transmits a session key and a session version to a user device whenever a subscriber to a home network changes, and the user device determines a session key using the session version, thereby performing a variety of domain administration by freely transmitting content between user devices.

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: The present invention relates to a method of preparing a microcapsule with a double-layered structure which comprises the steps of performing an interfacial polymerization of an amine-aldehyde prepolymer on droplets containing an inorganic metal precursor selected from carboxylate and alkoxide compounds, and hydrolyzing the including inorganic precursors for formation of inorganic inner layer. The method of the present invention can prepare a microcapsule with a double-layered structure of an inorganic inner layer and a polymer outer layer, which is effective for eluting and substituting a core material inside the capsule.

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: The present invention relates to aromatic polyether resins crosslinked with amic acid or imide side chain, and more particularly, to the aromatic polyether resin crosslinked by amic acid or imide side chain, which is produced by heat curing of amic acid, wherein introduction of imide groups to the basic backbone provides excellent chemical resistance as well as heat resistance and improves surface roughness when coated as a thin film so that it can be suitable for films and flexible display plate substrate.

Abstract: A method of measuring round trip time (RTT) and a proximity checking method using the same. The method of measuring RTT includes: transmitting a hashed second random number and starting the RTT measurement; and receiving a hashed first random number from a device that received the hashed second random number and ending the RTT measurement, thereby greatly reducing repetitive encryption and decryption operations in the proximity check using a repetitive RTT measurement.

Abstract: A scheduled recording method, which schedules recording of copy-protected content, is provided. The scheduled recording method involves determining whether copy control information of content of interest exists in a recording device storing various copy control information; if the copy control information does not exist in the recording device, newly receiving copy control information and then determining whether the copy control information exists among the newly received information; if the copy control information of the content exists in the recording device, determining whether the copy control information “copy never”; and if the copy control information of the content is “copy never”, transmitting an error message to a user indicating that the content of interest is not recordable to a user.

Abstract: A method of surface modifying a polyimide film, a method of manufacturing a flexible copper clad laminate using the same, and a flexible copper clad laminate (FCCL) having a two-layer structure manufactured thereby. The method of surface modifying a polyimide film is conducted by modifying the surface of a polyimide film through a first plasma treatment, dipping the polyimide film into a solution containing an ethyleneimine-based silane coupling agent prepared by mixing the compound of Formula 1 and the compound of Formula 2 at a molar ratio of with 0.25˜1, and then modifying the surface of the polyimide film through a second plasma treatment. The method of surface modifying a polyimide film is advantageous because it may be substituted for a conventional surface treatment processes using ion beams.

Abstract: An analog/digital signal processor outputting analog input signals without eliminating copy protection signals from analog input signals, analog input signals having been subjected to copy protection process such as macrovision without adding complicated processes. The analog/digital signal processor for receiving input signals and outputting received input signals to a predetermined appliance through an analog or a digital communication unit, includes: a control unit determining whether the input signals are digital or analog signals and controlling a processing path and an output path of the input signals in accordance with the determination result; and a switching unit switching the input signals to the analog or the digital communication unit under the control of the control unit. When the input signals are analog signals, the control unit sets the processing path of the input signals to the switching unit and the switching unit switches the input signals to the analog communication unit.

Abstract: A method and an apparatus for providing content encrypted in a broadcast encryption scheme to a plurality of devices in a local network are provided. The method includes: storing a minimal number of keys needed by the devices to decode the encrypted content among a plurality of keys that can be used in the predetermined encryption scheme; and transmitting the stored keys to the devices. Accordingly, it is possible for a local server having a small storage capacity to provide the encrypted content to the devices by storing only the minimal number of keys needed by the devices to decode the encrypted content.

Abstract: A method and apparatus for encrypting or decrypting digital content are provided. In the method, a binding range is selected from a plurality of binding ranges of content use based on license information of the content, and the content is encrypted based on the selected binding range so that the content can be used only within the selected binding range. Accordingly, it is possible to limit content use to a plurality of binding ranges of use of the content, using license information of the content.

Abstract: A method of measuring round trip time (RTT) and a proximity checking method using the same. The method of measuring RTT includes: transmitting a hashed second random number and starting the RTT measurement; and receiving a hashed first random number from a device that received the hashed second random number and ending the RTT measurement, thereby greatly reducing repetitive encryption and decryption operations in the proximity check using a repetitive RTT measurement.

Abstract: A method and apparatus of protecting digital content within a domain is provided. if a device registered with a domain withdraws from the domain, a domain key used in the domain before withdrawal of the device is updated to a domain key which cannot be used by the device; and the domain key not exposed to the device is transmitted to a plurality of devices currently registered with the domain so that only the currently registered devices have the most recent domain key. Therefore, devices not registered with the domain and devices which previously registered with the home domain but withdrawn from the home domain can be prevented from using digital content currently shared within the domain. In addition, registered devices that withdraw from the home domain may use digital content legitimately downloaded from the home domain before they withdrew from the domain.

Abstract: A revocation key determining method for content protection. The revocation key determining method includes: identifying at least one of a plurality of groups on the basis of a structure in which groups, each consisting of nodes to which key sets for content protection are respectively assigned, are hierarchically arranged in a tree form; and detecting whether nodes belonging to the group are respectively revoked.