Samsung Electronics Co., Ltd.

Jae-heung Lee

Myung-Sun Kim

Sung-hyu Han

Young-sun Yoon

Bong-seon Kim

Sun-nam Lee

Su-hyun Nam

Yong-jin Jang

Yang-lim Choi

Yong-kuk You

Myung-sun Kim

Moon-young Choi

Noh-byung Park

Sang-su Choi

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.

Method and apparatus for efficiently encrypting/decrypting digital content according to broadcast encryption scheme

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.

Key management method using hierarchical node topology, and method of registering and deregistering user using the same

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.

System and method for building home domain using smart card which contains information of home network member device

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.

Method of controlling content access and method of obtaining content key using the same

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. Therefore, the unauthorized copying of broadcast contents transmitted through a digital broadcast receiver can be prevented.

Method of packaging broadcast contents

A method for transmitting content to a user device from a home server in a home network is provided. The method includes: receiving an allocated user public key and a user private key of a user to whom the home server belongs; generating an arbitrary session public key and a session private key, generating an encrypted session private key by encrypting the session private key using a device public key that is a public key of the user device, and transmitting the encrypted session private key to the user device; and transmitting the content encrypted using a predetermined content key and a content key encrypted using the session private key to the user device. According to the method, by binding the content to each user, instead of to each device, the content can be safely and conveniently shared.

Method for transmitting content in home network using user-binding

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.

Method and apparatus for managing digital content

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.

Method and apparatus for backing up and restoring domain information

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.

Method and apparatus for checking proximity between devices using hash chain

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.

Encryption/decryption method and apparatus for controlling content use based on license information

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.

Home network system and method therefor

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.

Method of receiving session key in home network and method of reproducing content using the same

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.

Scrambling apparatus and method using conversion of motion vector information of video data

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.

Method and apparatus for limiting number of times contents can be accessed using hash chain

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.

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Suwon-si, South Korea

Jae-heung Lee