Abstract: A method and apparatus for generating and updating a license for content and for providing content are provided. The method of generating a license includes generating license signature information for authenticating the license; generating use rule information for controlling the use of the content; generating authentication code information for authenticating a coupon for changing at least a portion of the use rule information; and generating key information required for decrypting the content.

Abstract: Provided is a method of transmitting content processed according to first digital rights management (DRM) to a device that uses second DRM. The method includes generating a ticket using a first license server and a second license server, the first license server issuing a first license for use in the first DRM and the second license server issuing a second license for use in the second DRM; the second device obtaining a second content key required to process the content using the ticket and the second DRM; and the second device receiving the content from the first device and processing the content using the second content key and the second DRM. The ticket includes use control information that specifies a restriction of use of the content, and the second content key required to process the content using the second DRM.

Abstract: Disclosed are a method of multi-streaming encrypted contents stored in a storage medium to a second player during streaming the contents to a first player, and an apparatus using the same. The method includes: temporarily storing the encrypted contents streaming to the first player in a temporary storage medium; and streaming the stored contents to the second player in response to a multi-streaming command input by a user to the second player, wherein key generation information required to decrypt the encrypted contents is not stored in the temporary storage medium. It is possible to provide a multi-streaming with a copy protection through temporary storage, and also to reduce noise caused by rotation of the disc in the streaming apparatus.

Abstract: Provided is a contents decoding method using a digital rights management (DRM) card. The method of decoding contents received from a host device connected with a DRM card storing DRM software includes: receiving encrypted contents information from the host device and granting a contents decoding request; executing the DRM software corresponding to the contents information and decoding the received contents; and transmitting the decrypted contents to the host device, thereby using various pieces of contents regardless of a DRM system set in contents and easily upgrading DRM software to defend against hacking. Further, a host device does not require DRM software, which enables mass production and reduces manufacturing costs.

Abstract: A method and apparatus for generating and updating a license for content and for providing content are provided. The method of generating a license includes generating license signature information for authenticating the license; generating use rule information for controlling the use of the content; generating authentication code information for authenticating a coupon for changing at least a portion of the use rule information; and generating key information required for decrypting the content.

Abstract: An apparatus and a method for providing secure time, an apparatus and a method for securely reproducing contents using the secure time, and a method of securely transmitting data using the secure time. The apparatus for providing the secure time includes a clock whose time can be changed, a time difference storing unit storing a time difference between the correct time and the time of the clock, a time difference setting unit performing a time difference setting process of calculating a time difference and storing the time difference in the time difference storing unit when the time of the clock is changed, and a time providing unit providing the correct time by using the time of the clock and the time difference. Advantages of user convenience and cost savings can be obtained through the use of a single clock whose time can be freely changed by a user. A secure clock that can provide the correct time can be embodied as a software program.

Abstract: A method of revoking a public key of a content provider is provided. In a system in which a certificate authority certifies the public key of the content provider and the content provider transmits predetermined content to a user device using the certified public key, the method includes the user device determining whether the predetermined content is revoked by comparing a time when a signature of the public key is generated with a time when the public key is revoked. Accordingly, it is possible to allow the user device to identify content that must not be revoked according to the time when the public key is revoked and a revocation list which includes an exception list, thereby preventing rightly obtained content from being revoked.

Abstract: A digital rights management (DRM) conversion method and apparatus are provided. The DRM conversion method includes: (a) obtaining a first content key for the first content and a second content key for the second content through reciprocal authentication between a DRM conversion apparatus and a DRM conversion server, the DRM conversion apparatus converting the first content into the second content; and (b) converting the first content into the second content wherein the DRM conversion apparatus is disconnected from the DRM conversion server. Accordingly, it is possible to transmit content between devices using different DRM systems even offline with the use of a conversion manager (CM) that performs authentication and DRM conversion operations.

Abstract: An apparatus and method for securely storing data. The apparatus for securely storing data in a predetermined device, includes: a key generator generating a protection key used to encrypt data based on a random number generated by inputting predetermined secret information in a predetermined random number generation function, and generation sequence information, which is information on a generation sequence of the random number, wherein the predetermined secret information is stored in a secure region, and the random number generation function can generate the protection key based on the generation sequence information and the secret information. As described above, the apparatus and method for storing data make it possible to securely store data even if the apparatus for storing data is replaced.

Abstract: Provided are an apparatus and method for storing data. The apparatus includes a directory key generator generating a directory key required for encrypting and decrypting the data by inputting a device-specific key to a key generating function, the device-specific key being unique information allocated to the device and stored in a secure region of the device. The data is stored in at least one directory, and the directory key is used in encrypting and decrypting the data in units of directories. Accordingly, it is possible to minimize consumption of resources required to encrypt and decrypt the data.

Abstract: A method of authenticating a device having its own device key allocated by an authentication server according to broadcast cryptography is disclosed. The method includes receiving a device identifier of the device and an encrypted device identifier generated by encrypting the device identifier with the device key; and examining whether or not the device identifier is identical to a decrypted device identifier generated by decrypting the encrypted device identifier with another device key corresponding to the device identifier. Therefore, it is possible to authenticate a device having its own device key allocated by an authentication server according to broadcast cryptography without using a separate public key structure.

Abstract: Disclosed are a method of multi-streaming encrypted contents stored in a storage medium to a second player during streaming the contents to a first player, and an apparatus using the same. The method includes: temporarily storing the encrypted contents streaming to the first player in a temporary storage medium; and streaming the stored contents to the second player in response to a multi-streaming command input by a user to the second player, wherein key generation information required to decrypt the encrypted contents is not stored in the temporary storage medium. It is possible to provide a multi-streaming with a copy protection through temporary storage, and also to reduce noise caused by rotation of the disc in the streaming apparatus.

Abstract: Provided are a system and a method for transmitting and receiving contents at home. The content service method includes: reconstructing encrypted compressed contents back into compressed contents by decrypting the encrypted compressed contents according to a first scheme; encrypting the reconstructed compressed contents according to a second scheme; and transmitting the encrypted compressed contents via a predetermined link. Therefore, the encrypting and decrypting of contents are easily supported without an encoding process in a content server terminal at home.

Abstract: A streaming apparatus and method that streams AV data to other devices and converts the recording time stamp into a streaming time stamp format, thereby simplifying the streaming process.

Abstract: A method of transmitting copy control information in a video data transmitting/receiving system is provided. The method includes: decoding compressed contents into prior-to-compression contents; generating packets including the decoded contents and the copy control information; and transmitting the packets through a predetermined link. An unauthorized copying of the decoded video data is prevented.

Abstract: Provided is a method of transmitting content processed according to first digital rights management (DRM) to a device that uses second DRM. The method includes generating a ticket using a first license server and a second license server, the first license server issuing a first license for use in the first DRM and the second license server issuing a second license for use in the second DRM; the second device obtaining a second content key required to process the content using the ticket and the second DRM; and the second device receiving the content from the first device and processing the content using the second content key and the second DRM. The ticket includes use control information that specifies a restriction of use of the content, and the second content key required to process the content using the second DRM.