Abstract: An embodiment of the present disclosure discloses tobacco material including: a center portion including a flavor material; and an outer portion including a tobacco mixture, wherein the outer portion surrounds the center portion.

Abstract: The present invention relates to a method of manufacturing polycrystalline silicon ingot using a crucible in which an oxygen exhaust passage is formed by single crystal or polycrystalline rods, the method including the steps of: manufacturing the single crystal or polycrystalline silicon rods each having the shape of a quadrilateral pillar; putting the single crystal or polycrystalline quadrilateral pillar-shaped silicon rods into the crucible in such a manner as to be arranged close to one another along the inner peripheral surface of the crucible to thus form a space portion inside the single crystal or polycrystalline silicon rods, into which silicon chunks are put, and the oxygen exhaust passages between the inner peripheral surface of the crucible and the respective surfaces of the single crystal or polycrystalline silicon rods oriented toward the inner peripheral surface of the crucible; putting the silicon chunks into the space portion of the crucible; and melting and crystallizing the silicon chunks.

Abstract: A method of controlling transmission of content data includes establishing a communication channel with an external device; transmitting the content data through the communication channel to the external device; verifying a plurality of times whether the content data is transmitted to the external device within an acceptable transmission range to generate a verification result; and determining whether to continue transmitting the content data according to the verification result. The verification is periodically performed according to an amount of the content data to be transmitted.

Abstract: A method of controlling transmission of content data includes establishing a communication channel with an external device; transmitting the content data through the communication channel to the external device; verifying a plurality of times whether the content data is transmitted to the external device within an acceptable transmission range to generate a verification result; and determining whether to continue transmitting the content data according to the verification result. The verification is periodically performed according to an amount of the content data to be transmitted.

Abstract: Provided are a method and apparatus for controlling transmission of content data. In the method, a communication channel is initially established to transmit the content data, the content data is transmitted through the established communication channel, verification is performed a plurality of times to determine whether the content data is transmitted within an acceptable transmission range, and whether to continue the transmission of the content data is determined according to the verification result. Accordingly, when a client moves to a location outside a predetermined acceptable transmission range in a wireless environment, a server stops transmission of the content data. In addition, content data can be continuously transmitted regardless of interference caused by a temporary obstacle between a server and a client.

Abstract: A method of and apparatus for encrypting and/or decrypting content according to broadcast encryption scheme. The decryption method includes: determining whether or not a revoked device among devices that have licenses for predetermined content is present; and according to the determination result, selectively decrypting a content key encrypted by using a key to prevent the revoked device from decrypting the predetermined content. By doing so, an unnecessary encryption process and decryption process that occur when there is no revoked device are avoided.

Abstract: A key management, user registration and deregistration for a digital rights management (DRM) system in a home network, using a hierarchical node topology. In the key management, node information is generated by allocating a pair of keys (a public key and a private key) to each node. A node tree is made by generating link information using the pair of keys and a content key. The link information is delivered from an upper node to a lower node using the node tree. The link information is obtained by encrypting a private key of a ‘TO’ node using a public key of a ‘FROM’ node. Accordingly, it is possible to realize a DRM system that protects content and easily accomplishes a binding mechanism and a revocation mechanism.

Abstract: Provided is a method of controlling content access in a home network. The method includes: (a) defining a predetermined sub group and allocating a sub group key for the sub group; and (b) checking whether a user belongs to the sub group and transmitting the sub group key to a user device requested by the user, wherein the user device obtains an encrypted content key using a domain key and the sub group key. Since a content key is twice encrypted using a domain key and a sub group key and transmitted to a user device, it is possible to provide authorized content access to a user.

Abstract: A method of packaging broadcast contents are provided. The method includes: extracting a copy control bit from input broadcast contents and determining whether the broadcast contents will be stored after being encrypted based on the extracted copy control bit; creating usage rule information which includes an encryption method of the broadcast contents if it is determined that the broadcast contents will be stored after being encrypted; extracting the copy control bit from each new broadcast content sequentially input and detecting broadcast contents which include copy control bits indicating that the broadcast contents will be stored without being encrypted; and encrypting the input broadcast contents through the broadcast contents before the detected broadcast contents using the encryption method and packaging and storing the encrypted broadcast contents and the usage rule 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 of managing a home network key in a home network environment, which has a key management server for managing the home network key and a plurality of home network devices, includes: allowing a home network device to generate device unique information and to transmit the device unique information to the key management server; allowing the key management server to generate a parameter for generating the home network key by using the device unique information and to transmit the parameter to the home network device; and allowing the home network device to generate the home network key by using the parameter. The generated home network key being independent of the device unique information.

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: 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 and apparatus for encoding data, and a method and apparatus for decoding data. The method of encoding data including generating first encoded data by encoding input data, dividing the first encoded data into a plurality of segments, and generating second encoded data by combining the plurality of segments and dummy data.

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: 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: 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.