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 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: Methods of authenticating a device using a certificate, and digital content processing devices for performing device authentication using the methods are disclosed.

Abstract: A method of creating a domain based on public key cryptography includes providing, by a content-providing server, a list of devices requesting content, and selecting, by a user, a device from the list; transmitting, by the server, discrimination information on revoked devices to the device; extracting, by the device having received the discrimination information, a secret value from the discrimination information, preparing a certificate using the extracted secret value, and transmitting device information and the certificate of the device to the server; verifying, by the server, the certificate and creating a domain ID and a domain key using the device information; encrypting, by the server, the domain ID and the domain key using a unique public key of the device and transmitting the encrypted domain ID and domain key to the device; and restoring, by the device, the domain key using a unique secret key of the device.

Abstract: Disclosed is a domain authentication method for exchanging content between devices. The domain authentication method for exchanging content between devices according to the present invention includes a first step of setting domain identification information into a predetermined device connected on a wired/wireless network; a second step of generating a domain secret key using the set domain identification information and predetermined device identification information; a third step of generating a predetermined first code value and transmitting a first packet encrypted with the first code value using the domain secret key generated in the second step; a fourth step of receiving a second packet that is encrypted with the first code value and a second code value; and a fifth step of decrypting the second packet received in the fourth step.

Abstract: A method of establishing a home domain capable of reproducing multimedia content, and a smart card therefor. The method includes creating a domain certificate for a reproducing device by inserting the smart card into the reproducing device, creating a session key by inserting the smart card into a home server, and verifying the domain certificate of the reproducing device and transmitting the created session key to the reproducing device if the device is a legitimate device. Alternatively, the method includes using an external certificate authority to determine whether the reproducing device is a legitimate device.

Abstract: A system for authenticating a content user, comprising a group common key that authenticates a user, a private key owned by the user, a trusted organization adapted to create and distribute the group common key, and to store personal information on the authenticated user and a temporary registration certificate issued to the authenticated user. A user apparatus converts the temporary registration certificate by means of a predetermined conversion method using the private key, and further provides the converted temporary registration certificate to a content provider prior to executing content provided by the content provider the content provider adapted to check whether the user has been authenticated by the trusted organization, using the group common key prior to providing the content.