Abstract: A multimedia device having an encryption module, which prevents an encryption key from being exposed to the outside, is provided. The multimedia device includes: a key processing unit, which generates and manages an encryption key; and a data processing unit, which encrypts/decrypts content with the encryption key. Both the key processing unit and the data processing unit are located in the encryption module. The encryption module can generate an encryption key and encrypt content with the encryption key, independently of an external device, such as a CPU. In addition, the encryption module encrypts the encryption key before transmitting the encryption key to the CPU to record the encryption key on a storage medium. Therefore, it is possible to protect the content and the encryption key from hacking threats by preventing the encryption key from being exposed to the outside of the encryption module.

Abstract: A color image segmentation method is provided. The color image segmentation method includes the steps of: (a) calculating a first value representing the degree of difference between a pixel and the color of peripheral pixels based a plurality of pixel values of an input image; (b) obtaining a converted image by converting the first calculated value into a value of a predetermined scale; and (c) segmenting the converted image. According to the color image segmentation method, an effective and an automatic segmentation is possible, and a segmentation speed is high even when segmenting an image containing much noise.

Abstract: A color image processing method and apparatus thereof are provided. The color image processing method includes the steps of (a) sorting image pixels according to the color distance between the image pixels and a central pixel, (b) grouping the sorted pixels into groups in which the difference in the intragroup color distance is minimum and the difference in the intergroup color difference is maximum, and (c) performing filtering by replacing a central pixel value with a predetermined pixel value determined by pixel values of pixels in the groups. The color image processing method can reduce the generation of edge blurring of the image in removing impulse noise from an image and filtering the same.

Abstract: A method and apparatus for restricting the use of a disc are provided. In this method, first, lead-in data is read out from a loaded disc. Then, a user key is read out from a lead-in area of the disc. Thereafter, the user key undergoes authentication based on a user key received from a host. The authentication is performed by comparing a random number produced by a disc drive with a decrypted random number obtained by the disc drive decrypting a random number encrypted by the host. Accordingly, the use of the disc by an unauthorized third person is restricted, thus preventing a leakage of personal information and a protection of the copyrights of data.

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: An object activity modeling method which can efficiently model complex objects such as a human body is provided. The object activity modeling method includes the steps of (a) obtaining an optical flow vector from a video sequence; (b) obtaining the probability distribution of the feature vector for a plurality of video frames, using the optical flow vector; (c) modeling states, using the probability distribution of the feature vector; and (d) expressing the activity of the object in the video sequence based on state transition. According to the modeling method, in video indexing and recognition field, complex activities such as human activities can be efficiently modeled and recognized without segmenting objects.

Abstract: A method and apparatus for reporting the operation state of digital rights management are provided. In a home network formed with control devices and a control point, the apparatus for reporting the operation state of digital rights management of the control device to the control point includes: a digital rights management (DRM) module which performs digital rights management; a state variable generation unit which receives DRM operation state information indicating the state of a DRM process currently operating, from the DRM module, and based on the received DRM state information, generates DRM state variables; and a universal plug and play (uPnP) module which by using a uPnP protocol, transmits the generated state variables to the control point.

Abstract: A data recording medium, a recording apparatus thereof, and an apparatus for providing contents having a function of securing personal anonymity similar to a prepaid card. The prepaid card type data recording medium includes a control information area on which is recorded coupon ID information for identifying the data recording medium and representing the authority for recording contents. In addition, marginal capacity information for indicating the maximum downloadable capacity of contents may further be recorded on the control information area. The apparatus for providing contents includes an authentication unit for authenticating personal identification information, and a contents upload unit for uploading predetermined contents to the data recording medium when the authentication is successful in the authentication unit.

Abstract: An apparatus and method for updating copy control information. The apparatus and method can update copy control information of input data with user-defined copy control information. The apparatus includes a copy control information detection unit, which detects copy control information from input data; a copy control information input unit, which receives user-defined copy control information from a user; and a copy control information update unit, which updates the copy control information of the input data with the user-defined copy control information. The copy control information update unit may update the copy control information of the input data with the user-defined copy control information only when the user-defined copy control information imposes a stricter restriction on copying the input data than the copy control information of the input data does.

Abstract: A method of assigning user keys for broadcast encryption. According to the method, at least one unit tree in which grandparent nodes, parent nodes, and son nodes are hierarchically connected is created. User keys created to identify lower-level nodes connected to all nodes of the tree are assigned as first user keys of the nodes for all nodes of the tree, and node identification user keys of the son nodes except for the son node included in the unit tree among node identification user keys that identifies son nodes included in unit trees are assigned as second user keys of the son nodes.

Abstract: A data retransmission device and method are provided that can simultaneously implement link protection and internal protection without increasing design complexity and cost. A data retransmission device for encrypting input data and retransmitting the encrypted data to a predetermined device includes an input data processing unit receiving the input data, coding the input data in a format suitable for the predetermined device, and encrypting the input data with a common key to be shared with the predetermined device, and a link protection unit receiving the encrypted input data from the input data processing unit via a predetermined bus and retransmitting the received data to the predetermined device. In addition, the common key is created in the link protection unit and transmitted to the input data processing unit via the predetermined bus.

Abstract: Provided is a method of copying data stored in a first storage medium to a second storage medium. The method includes recording the encrypted data stored in the first storage medium on the second storage medium; reproducing a first content key, which is used to encrypt the encrypted data, using a first drive into which the first storage medium is loaded; encrypting the first content key; sending the encrypted first content key to a second drive into which the second storage medium is loaded; and recording the encrypted first content key on the second storage medium. In this method, encrypted data stored in a first storage medium is sent to a second storage medium via a host without decrypting the encrypted data, thereby preventing the data from being hacked or being accessed by unauthorized users and increasing a speed of copying the encrypted data.

Abstract: A method is provided for indexing feature vectors within feature vector data space which includes adaptively forming approximation of the feature vectors on the basis of statistical distribution of feature vector data within the feature vector data space. The method for indexing feature vector data space of the present invention efficiently indexes vector space having high-dimensionality in which generally feature vectors are not uniformly distributed. Also, the method for indexing feature vector data space has an advantage that indexing can be easily upgraded when new feature vector data is added.

Abstract: A method and apparatus for recording data on and/or reproducing data from a storage medium are provided. The recording apparatus includes an authenticating unit which authenticates a host, which transmits a write command to the apparatus, to verify whether the host is authentic; at least one job module which generates output information by processing the user data, which is included in the write command, based on disc information stored in the storage medium and device information stored in the apparatus, in response to the write command; a module selecting unit which selects the job module based on module selection information and sends the write command to the selected job module, when the host is determined to be authentic, the module selection information being contained in the write command and specifying the job module; and a recording unit which records the output information on the storage medium.

Abstract: An adaptive search method in feature vector space which can quickly search the feature vector space indexed based on approximation for a feature vector having features similar to a query vector according to a varying distance measurement is provided. The adaptive search method includes the steps of (a) performing a similarity measurement on a given query vector within the feature vector space, and (b) applying search conditions limited by the result of the similar measurement obtained in the step (a) and performing a changed similarity measurement on the given query vector. According to the adaptive search method, the number of candidate approximation regions is reduced during a varying distance measurement such as an on-line retrieval, which improves the search speed.

Abstract: Provided are an information storage medium from which a total number of times that data can be reproduced is limited, a method and apparatus for recording data on the information storage medium, and a method and apparatus for reproducing data from the information storage medium. The information storage medium includes a data zone storing user data, and a control information zone storing control information regarding controlling a number of times that the user data can be reproduced. Accordingly, a content provider who provides content such as a movie can create various types of business models by recording content on the aforementioned information storage medium, and selling it at a cheaper price. Further, control information is recorded on the information storage medium or a write once zone of the information storage medium before recording content or user data thereon, thereby preventing the control information from being changed or deleted.

Abstract: A home domain building method and system that allow devices to join a home domain using smart cards. In the method, a master device reads device information from a smart card having a device ID and a device key as the device information of a guest device authenticated as a legal device and transmits a challenge request signal to the guest device, the guest device randomly generates a challenge value in response to the challenge request signal, the master device encrypts the challenge value using the device key of the guest device and transmits the encrypted challenge value to the guest device, the guest device decrypts the encrypted challenge value, and if the decrypted challenge value is the same as the challenge value generated in response to the challenge request signal, the guest device allows the master device to join the guest device in the home domain.

Abstract: A method of and an apparatus for copying and decrypting encrypted digital data. The method of copying encrypted digital data includes encrypting a first media key block to be used for decryption of the encrypted digital data using a predetermined key of a second information storage medium and storing the encrypted digital data and the encrypted first media key block in the second information storage medium. Security of data encryption is heightened by not discarding an encryption key used for an initial encryption, encrypting the encryption key used for initial encryption using another encryption key used for a second encryption, and storing the encrypted encryption key with the data. Also, since unnecessary decryption and encryption of data are not repeated, the time required for copying data is reduced, and since data is transferred between apparatuses in an encrypted state, a security level is higher.

Abstract: An audio and/or video (AV) stream copy method, an AV stream copy apparatus, and an AV contents copy control method, in which AV content includes an AV stream, are disclosed. The apparatus for copying an AV stream includes an AV stream copy controller, which, when an input copy command does not correspond to copy control information (CCI) of the AV stream, gives instructions to input a CCI coupon including new CCI, extracts the new CCI from the input CCI coupon, and gives instructions to copy the AV stream; a CCI coupon input unit, which inputs the CCI coupon according to a CCI coupon input command of the AV stream copy controller; and an AV stream copy unit, which changes the CCI of the AV stream, according to an AV stream copy command of the AV stream copy controller, and the extracted CCI and copies the AV stream.

Abstract: A method of constructing a unique domain for preventing content from being illegally used by an unauthorized third person in a public key-based architecture and applying the constructed domain to a home network using universal plug and play (UPnP). The method of the present invention includes selecting one of controlled devices that are operable as a master device and determining the selected device as the master device; performing device authentication in such a manner that other controlled devices receive a secret information block from the determined master device and create certificates; and determining slave devices by selecting one or more devices among the authenticated controlled devices.