WO2009104844A1

WO2009104844A1 - Method and apparatus for recording or providing content

Info

Publication number: WO2009104844A1
Application number: PCT/KR2008/004731
Authority: WO
Inventors: Kil-Soo Jung; Joon-Hwan Kwon
Original assignee: Samsung Electronics Co., Ltd.
Priority date: 2008-02-19
Filing date: 2008-08-14
Publication date: 2009-08-27
Also published as: KR100965888B1; KR20090089639A

Abstract

Provided are a method and apparatus for recording content. The method includes transmitting a first disc key of a first disc loaded into the recording apparatus to the server; receiving, from the server, an encrypted title key obtained by encrypting a title key of content by using the first disc key; determining whether a second disc key of a second disc loaded into the recording apparatus is identical to the first disc key; and if the second disc key is identical to the first disc key, recording the content and the encrypted title key on the second disc. Accordingly, it is possible to prevent disc waste by allowing content to be recorded only on a specific disc.

Description

Description METHOD AND APPARATUS FOR RECORDING OR

PROVIDING CONTENT

Technical Field

[1] The present invention relates to a method and apparatus for providing or recording content, and more particularly, to a method and apparatus for recording content only on a specific disc, thereby preventing disc waste. Background Art

[2] Advances in digital technology have led to an increase in the amount and types of media signal recording apparatuses, such as digital televisions (DTV), digital versatile disc (DVD) players, and computers. Also, advances in communication technology have enabled a large amount of data to be sent or received within a short period of time via a wired/wireless communication network. Accordingly, a user can access a server managed by a content provider, including for example movie production companies and broadcasting companies, via a communication network, and then download content received from the server in the form of an audio signal, a video signal or a text signal to the user's recording apparatus. The user can use the downloaded content by recording the content on a hard disc included in the recording apparatus or an external storage unit inserted into the recording apparatus and then reproducing it therefrom. A storage medium on which a large amount of data can be recorded may be a DVD or a BD (Blue-ray disc).

[3] A digital rights management (DRM) technique is used in order to prevent a user from illegally copying or altering content downloaded from a server. The user can use the content after obtaining a right to revoke the DRM technique from a content provider. The DRM technique includes a content scrambling system (CSS) technique whereby content is reproduced through a multi-level decryption process using several keys. Through the CSS technique, it is possible to prevent content from being reproduced from a DVD by illegally copying the content to a hard disk driver (HDD), and prevent content stored in an HDD from being illegally recorded on and reproduced from another disc.

[4] FIG. 1 is a block diagram illustrating a method of reproducing content from a DVD

110 to which the CSS technique is applied. Referring to FIG. 1, encrypted disc keys, encrypted title keys and scrambled content are recorded on the DVD 110. A unique player key is allocated to a reproducing apparatus 120 that reproduces the content from the DVD 110. A player key is a value for decrypting an encrypted disc key. A unique player key is allocated to each reproducing apparatus that is to be capable of re- producing the content from the DVD 110. A disc key that is a unique disc value allocated to a disc, is information for decrypting an encrypted title key. The disc keys are encrypted with respective player keys which are allocated to reproducing apparatuses capable of recording data on or reproducing data from a disc, and are then recorded in a lead-in region of the DVD 110. The title key is a unique value allocated in a title of the content, and is used to decipher all of the encrypted title or a part thereof. The title key is stored in a header section of the title in an encrypted form.

[5] If a user loads the DVD 110 into the reproducing apparatus 120 in order to reproduce the content from the DVD 110, the reproducing apparatus 120 reads the encrypted disc keys from the lead-in region of the loaded DVD 110. The reproducing apparatus 120 detects a disc key encrypted with the unique player key of the reproducing apparatus 120 from among the read disc keys being respectively encrypted using a plurality of player keys, and then decrypts the detected disc key with the unique player key of the reproducing apparatus 120 in order to extract the disc key. The reproducing apparatus 120 extracts a title key by deciphering an encrypted title key stored in the header section of a desired title by using the extracted disc key. Then, the reproducing apparatus 120 can reproduce the content from the DVD 110 by descrambling the scrambled content using the extracted title key.

[6] FIG. 2 is a diagram illustrating a CSS managed recording system. The CSS managed recording system allows content to be downloaded via a communication network and recorded on a blank disc by applying a system for protecting content which is equivalent to those used in commercially sold DVDs, i.e., the CSS technique. Referring to FIG. 2, the CSS managed recording system includes a recording apparatus 200, a server 220 and a communication network 210. The recording apparatus 200 is connected to the server 220 via the communication network 210. The server 220 is managed by a content provider, such as a broadcasting company or a movie production company, and stores an audio signal, a video signal, a text signal, or a meta data signal thereof.

[7] A user can access and log in the server 220, and then select and download desired content in a scrambled form from the server 220. The user loads a disc (not shown) into the recording apparatus 200 in order to record the downloaded scrambled content on the disc. The recording apparatus 200 reads an encrypted disc key from a lead-in region of the loaded disc. The recording apparatus 200 extracts a disc key by decrypting the encrypted disc key by using a unique player key of the recording apparatus 200, and transmits the extracted disc key to the server 220 via the communication network 210. The server 220 generates an encrypted title key by encrypting the disc key received from the recording apparatus 200 by using the title key of the content that is to be recorded by the user, and then transmits the encrypted title key to the recording apparatus 200 together with or without the scrambled content. The recording apparatus 200 can download the encrypted title key and the scrambled content from the server 220, and record, on the disc, the scrambled content and the encrypted title key that is used to decrypt the scrambled content in order to reproduce the content.

[8] As described above, the recording apparatus 200 transmits a disc key of a specific disc on which content is to be recorded to the server 220, downloads a title key encrypted with the disc key from the server 220, and then records the encrypted title key together with scrambled content on the disc, so that the scrambled content can be descrambled and reproduced. However, the encrypted title key and the scrambled content downloaded from the server 220 may not be successfully recorded on the disc due to a problem of the recording apparatus 200. In this case, the user may record the downloaded encrypted title key and scrambled content on a new disc. Also, if the user transmits a disc key of a specific disc to the server 220 and downloads the encrypted title key and the scrambled content from the server 220 by using the transmitted disc key, the encrypted title key and the scrambled content may be recorded, by the user's mistake, on a new disc other than the specific disc.

[9] In this case, a reproducing apparatus decrypts the encrypted title key by using a disc key allocated to the new disc. However, the encrypted title key has been encrypted using the disc key of the specific disc. Thus, if the encrypted title key is decrypted using the disc key of the new disc that is different from that of the specific disc, a title key whose value is different from that of the original title key is obtained. Since the scrambled content cannot be deciphered using the title key having a value different from that of the original title key, the reproducing apparatus will not be able to reproduce the content. Accordingly, when the encrypted title key generated using the disc key of the specific disc is recorded on a disc other than the specific disc, the content cannot be reproduced, thus leading to waste of the disc. Disclosure of Invention Technical Solution

[10] The present invention provides a method and apparatus for recording content only on a specific disc, thereby preventing disc waste and preventing a user from mistakenly recording encrypted content on a wrong disk.

[11] The present invention also provides a method and a server for providing content in such a manner that the content can be recorded only on a specific disc, thereby preventing disc waste and preventing a user from mistakenly recording encrypted content on a wrong disk. Advantageous Effects [12] According to the above embodiments of the present invention, it is possible to provide a method and apparatus for recording content only on a specific disc, thereby preventing disc waste and preventing a user from mistakenly recording encrypted content on a wrong disk.

[13] Also, it is possible to provide a method and a server for providing content so that the content can be recorded only on a specific disc, thereby preventing disc waste and preventing a user from mistakenly recording encrypted content on a wrong disk. Description of Drawings

[14] The above and other features and advantages of the present invention will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings in which:

[15] FIG. 1 is a block diagram illustrating a method of reproducing content from a disc to which a content scrambling system (CSS) technique is applied;

[16] FIG. 2 is a diagram illustrating a CSS managed recording system;

[17] FIG. 3 is a block diagram of a content recording apparatus according to an embodiment of the present invention;

[18] FIG. 4 is a block diagram of a content recording apparatus according to another embodiment of the present invention;

[19] FIG. 5 is a block diagram illustrating the module construction of a server that performs a content providing method according to an embodiment of the present invention;

[20] FIG. 6 is a flowchart illustrating a content recording method performed by the recording apparatus of FIG. 3, according to an embodiment of the present invention;

[21] FIG. 7 is a flowchart illustrating a content recording method performed by the recording apparatus of FIG. 4, according to another embodiment of the present invention; and

[22] FIG. 8 is a flowchart illustrating a content providing method performed by a server of FIG. 3, according to an embodiment of the present invention. Best Mode

[23] According to an aspect of the present invention, there is provided a content recording method which is performed by a recording apparatus communicating with a server via a communication network, the method comprising transmitting a first disc key of a first disc loaded into the recording apparatus to the server; receiving, from the server, an encrypted title key obtained by encrypting a title key of content by using the first disc key; determining whether a second disc key of a second disc loaded into the recording apparatus is identical to the first disc key; and if the second disc key is identical to the first disc key, recording the content and the encrypted title key on the second disc. [24] The determining of whether the second disc key is identical to the first disc key may comprise decrypting the encrypted title key with second disc key; transmitting the result of decrypting to the server, together with a content identifier identifying the content; and receiving, from the server, the result of determining whether the result of decrypting is identical to the title key of the content identified by the content identifier. Also, the method may further include obtaining the first disc key by decrypting an encrypted first disc key recorded on the first disc by using a player key of the recording apparatus; and obtaining the second disc key by decrypting an encrypted second disc key recorded on the second disc by using the player key of the recording apparatus. Also, the recording of the content and the encrypted title key on the second disc may comprise determining that the second disc is identical to the first disc when the recording apparatus receives, from the server, the result of determining that the result of decrypting is identical to the title key of the content. When the recording apparatus receives, from the server, the result of determining that the result of decrypting is not identical to the title key of the content, the method may further include creating and outputting an image indicating that recording of the content and the encrypted title key on the second disc is not allowed. The determining of whether the second disc key is identical to the first disc key may be performed based on whether an encrypted second disc key extracted from the second disc is identical to an encrypted first disc key extracted from the first disc. The method may further include storing the encrypted title key received from the server, together with the content and the encrypted first disc key, so that the encrypted title key, the content and the encrypted first disc key belong to the same group. The recording of the content and the encrypted title key on the second disc may include receiving a command that the content and the encrypted title key are to be recorded on the second disc; extracting the stored encrypted first disc key belonging to the same group with the content and the encrypted title key, in response to the command; extracting the encrypted second disc key from the second disc; and determining whether the encrypted first disc key is identical to the encrypted second disc key. Also, if the encrypted first disc key is not identical to the encrypted second disc key, the method may further include creating and outputting an image indicating that recording of the content and the encrypted title key on the second disc is not allowed.

[25] According to another aspect of the present invention, there is provided a content providing method which is performed by a server communicating with a recording apparatus via a communication network, the method comprising receiving a first disc key of a first disc from the recording apparatus; generating an encrypted title key by encrypting a title key of content with the first disc key; transmitting the encrypted title key to the recording apparatus; receiving, from the recording apparatus, a result of decrypting the encrypted title key with a second disc key of a second disc; determining whether the result of decrypting received from the recording apparatus is identical to the title key of the content; and providing the result of determining to the recording apparatus.

[26] According to another aspect of the present invention, there is provided a content recording apparatus communicating with a server via a communication network, the apparatus comprising a communication unit exchanging information with the server via the communication network; a disc key decryption unit extracting a first disc key from a first disc loaded into the recording apparatus; a controller controlling the apparatus to transmit the extracted first disc key to the server and receive an encrypted title key obtained by encrypting a title key of content by using the first disc key, from the server; determining whether a second disc key of a second disc loaded into the recording apparatus is identical to the first disc key; and allowing the content and the encrypted title key to be recorded on the second disc if the second disc key is identical to the first disc key; and a recording unit recording the content and the encrypted title key on the second disc.

[27] According to another aspect of the present invention, there is provided a server for communicating with a recording apparatus via a communication network, the server comprising a transceiving unit exchanging information with the recording apparatus via the communication network; an encrypted title key generation unit generating an encrypted title key by encrypting a title key of content with a first disc key of a first disc, where the first disc key is received from the recording apparatus; a title key comparison unit determining whether the result of decrypting the encrypted title key with a second disc key of a second disc is identical to the title key of the content, where the result of decrypting is received from the recording apparatus; and a controller controlling the server to generate the encrypted title key, determine whether the result of decrypting is identical to the title key of the content, and provides the result of determining to the recording apparatus.

[28] According to another aspect of the present invention, there is provided a computer readable having recorded thereon a computer program for executing a content recording method which is performed by a recording apparatus communicating with a server via a communication network, the method comprising transmitting a first disc key of a first disc loaded into the recording apparatus to the server; receiving, from the server, an encrypted title key obtained by encrypting a title key of content by using the first disc key; determining whether a second disc key of a second disc loaded into the recording apparatus is identical to the first disc key; and if the second disc key is identical to the first disc key, recording the content and the encrypted title key on the second disc.

[29] According to another aspect of the present invention, there is provided a computer readable having recorded thereon a computer program for executing a content providing method which is performed by a server communicating with a recording apparatus via a communication network, the method comprising receiving a first disc key of a first disc from the recording apparatus; generating an encrypted title key by encrypting a title key of content with the first disc key; transmitting the encrypted title key to the recording apparatus; receiving, from the recording apparatus, the result of decrypting the encrypted title key with a second disc key of a second disc; determining whether the result of decrypting received from the recording apparatus is identical to the title key of the content; and providing the result of determining to the recording apparatus. Mode for Invention

[30] This application claims the benefit of Korean Patent Application No.

10-2008-0014910, filed on February 19, 2008, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference.

[31] Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[32] FIG. 3 is a block diagram of a content recording apparatus 300 according to an embodiment of the present invention. Referring to FIG. 3, the content recording apparatus

300 includes a user interface 310, a controller 320, a communication unit 330, a local storage unit 340, a recording unit 350, a storage medium 360, a disc key decryption unit 370, and a title key decryption unit 380. In some cases, although not shown, the recording apparatus 300 may further include a reading unit that reads data from the storage medium 360 or the local storage unit 340, and an output unit that performs signal processing on the read data and outputs the processing result.

[33] The recording apparatus 300 is connected to the server 301 via a communication network 210. The recording apparatus 300 can record content received from the server

301 on the storage medium 360 and may be a digital television (DTV), a computer, or a digital versatile disc (DVD) player. In the current embodiment, the recording apparatus 300 can perform a read operation in order to reproduce content from the storage medium 360 but the present invention is not limited thereto. That is, the recording apparatus 300 may be formed to only perform a write operation and not the read operation. The communication network 210 includes a wired/wireless communication network.

[34] The server 301 is managed by a content provider, such as a broadcasting company, a movie production company, or a general content creating company. The server 301 stores an audio signal, a video signal, a text signal, or a meta data signal thereof. In the present application, a title is used to be equivalent to content. In the present invention, since content contains an audio signal, a video signal, a text signal, or a meta data signal thereof, a title is used as a term including not only a video signal but also an audio signal, a text signal, and a meta data signal thereof. The server 301 scrambles various titles using at least one title key and stores the scrambled titles. Also, the server 301 stores title keys for decrypting the scrambled titles. Although FIG. 3 illustrates that the server 301 has a function of providing content, but a database (not shown) may perform the function of the server 301 in some cases.

[35] A user can receive user authentication by accessing and logging in the server 301, and then select and download desired content. If the desired content is not charge free, the user can download the content from the server 301 after paying a fee by transmitting payment information to the server 301.

[36] A user loads the storage medium 360, such as a disc, on which content is to be recorded into the recording apparatus 300. The recording apparatus 300 reads an encrypted disc key from a lead-in region of the loaded storage medium 360. The recording apparatus 300 extracts a disc key by decrypting the encrypted disc key with a unique player key of the recording apparatus 300, and transmits the extracted disc key to the server 301 via the communication network 210. The server 301 encrypts a title key of the content that is to be recorded by using the disc key received from the recording apparatus 300, and then transmits the encrypted title key to the recording apparatus 300. Hereinafter, a disc key that is transmitted from the recording apparatus 300 to the server 301 and is used for the server 301 to encrypt a title key of content selected by a user, will be referred to as a 'first disc key', and a disc from which the encrypted first disc key is extracted will be referred to as a 'first disc'.

[37] The recording apparatus 300 downloads a title key encrypted using the first disc key, and encrypted (scrambled) content to the local storage unit 340, and stores them therein. The encrypted content may be downloaded either together with or separate from the encrypted title key.

[38] Then, upon receiving from the user a command that the encrypted title key and the encrypted content be recorded on a disc being currently loaded into recording apparatus 300, the recording apparatus 300 determines whether the current disc is identical to the first disc. A disc that is currently loaded into the recording apparatus 300 and on which the user instructs the encrypted content and encrypted title key stored in the local storage unit 340 to be recorded, will be referred to as a 'second disc', so that the loaded disc can be distinguished from the first disc. The recording apparatus 300 determines whether the second disc is identical to the first disc, and records the encrypted content and title key to the second disc only when they are identical to each other. If the second disc is not identical to the first disc, the recording apparatus 300 creates and outputs an image indicating that the encrypted content and title key cannot be recorded on the second disc. [39] A method of determining whether the second disc is identical to the first disc will now be described by describing the constitutional elements of the recording apparatus 300. The user interface 310 that acts as an interface with a user, delivers the user's command to the controller 320. The user interface 310 includes a physical transducer, such as a keyboard mouse, a touch screen, or a microphone, and receives a command, characters, numbers or voice information from the user and delivers it to the controller 320.

[40] The communication unit 330 transmits or receives information by accessing the server 301 or the database via the wired/wireless communication network 210. Although not shown, if the communication unit 330 performs a radio communication, it may include a radio signal transceiving unit, a base-band processor, and a link controller. The base-band processor and the link controller exchange a control command and data with the controller 320 by exchanging host control interface (HCI) packets with the controller 320 while being connected to the controller 320 via an HCI. The radio communication may use a wireless local area network (WLAN), bluetooth, zigbee, or WiBro.

[41] The local storage unit 340 stores information downloaded from the server 301 or the data base by the communication unit 330. In the current embodiment, the local storage unit 340 downloads the encrypted title key from the server 301 and stores it, where the encrypted title key is obtained by encrypting the title key, which is used to decrypt the encrypted content and the encrypted content, by using the first disc key. As described above, the first disc key is a disc key that the recording apparatus 300 transmits to the server 301, and is used for the server 301 to encrypt a title key for predetermined content.

[42] The recording unit 350 records the encrypted title key and content stored in the local storage unit 340 on the storage medium 360 loaded into the content recording apparatus 300.

[43] The disc key decryption unit 370 extracts the encrypted disc key from the second disc loaded into the recording apparatus 300. If the first disc is loaded into the recording apparatus 300, the disc key decryption unit 370 extracts the encrypted first disc key from the first disc, and obtains the first disc key by deciphering the encrypted first disc key with the unique player key of the recording apparatus 300. The disc key decryption unit 370 transmits the obtained first disc key to the server 301 via the communication unit 330. Then, if the second disc is loaded into the recording apparatus 300, the disc key decryption unit 370 extracts an encrypted second disc key from the second disc, and obtains a second disc key by deciphering the encrypted second disc key with the unique player key of the recording apparatus 300. The disc key decryption unit 370 transmits the obtained second disc key to the title key decryption unit 380. [44] If a user instructs that content be recorded on a currently loaded disc, i.e., the second disc, the title key decryption unit 370 decrypts the encrypted title key stored in the local storage unit 340 by using the second disc key extracted from the second disc. The encrypted title key stored in the local storage unit 340 has been encrypted with the first disc key. Thus, when the first disc key is identical to the second disc key since the first disc is identical to the second disc, the result of decrypting is the same as the title key of the content. However, when the first disc key is not identical to the second disc key since the first disc is not identical to the second disc, the result of decrypting by the title key decryption unit 380 is not the same as the title key of the content. The title key decryption unit 380 transmits the result of decrypting to the server 301 via the communication unit 330.

[45] The controller 320 controls the overall operation of the recording apparatus 300 in order to perform a content recording method according to the present invention. The controller 320 includes an arithmetic logic unit (ALU) that makes a calculation, and a register that temporarily stores data and commands. The controller 320 controls the disc key decryption unit 370 to extract the first disc key from the loaded storage medium 360. The controller 320 transmits the first disc key to the server 301 via the communication unit 330, and downloads the title key for the content encrypted with the first disc key from the server 301. The controller 320 stores the downloaded encrypted title key and encrypted content in the local storage unit 340.

[46] Next, upon receiving a command that the encrypted content and title key stored in the local storage unit 340 be recorded on the currently loaded disc, i.e., the second disc, from a user via the user interface 310, the controller 320 determines whether the second disc is identical to the first disc. To this end, the controller 320 controls the disc key decryption unit 370 to extract the second disc key from the second disc, and controls the title key decryption unit 380 to decrypt the encrypted title key stored in the local storage unit 340 with the second disc key. The controller 320 transmits the result of decrypting together with a content identifier identifying the content to the server 301. The server 301 searches for the content identified using the content identifier, and extracts a unique title key allocated to the identified content. The server 301 determines whether the result of decoding received from the recording apparatus 300 is identical to the title key of the identified content and then provides the result of determining to the recording apparatus 300, where the result of decoding is the result of decoding the title key that has been encoded using the first disc key, with the second disc key. If the result of determining reveals that the result of decoding is identical to the title key of the content, the controller 320 determines that the second disc is identical to the first disc and controls the recording unit 350 to be recorded on the encrypted content and title key stored in the local storage unit 340 on the second disc. If the result of determining reveals that the result of decoding is not identical to the title key of the content, the controller 320 controls the output unit to create and output an image indicating that the encrypted content and title key cannot be recorded on the second disc.

[47] The reading unit reads data from the local storage unit 340 or the storage medium

360 and transmits the read data to the output unit. The output unit decodes the read data in order to convert it in a format in which the data can be output, and then outputs the converted signal. Also, the output unit outputs the overall state of the recording apparatus 300 or information input by a user via the user interface 310, using a screen or a speaker. Although not shown, the output unit includes a display unit that outputs a video signal and a speaker that outputs an audio signal. The output unit may include an on-screen display (OSD) processor that creates and outputs a user controlled list. If a user tries to record the encrypted title key and content stored in the local storage unit 340 on the second disc that is not identical to the first disc, the output unit creates and outputs an image indicating that the encrypted title key and content cannot be recorded on the second disc.

[48] FIG. 4 is a block diagram of a content recording apparatus 400 according to another embodiment of the present invention. Referring to FIG. 4, the content recording apparatus 400 includes a user interface 410, a controller 420, a communication unit 430, a local storage unit 440, a recording unit 450, a storage medium 460, a disc key decryption unit 470, and a disc comparison unit 480. In some cases, although not shown, the content recording apparatus 400 may further include a reading unit that reads data from the storage medium 460 loaded into the content recording apparatus 400, and an output unit that performs signal processing on the data read from the storage medium 460. As described above with reference to FIGS. 2 and 3, the content recording apparatus 400 accesses the server 401 via a communication network 210.

[49] The operations of the user interface 410, the communication unit 430, the recording unit 450, the storage medium 460, and the disc key decryption unit 470 included in the content recording apparatus 400, are respectively the same as those of the user interface 310, the communication unit 330, the recording unit 350, the storage medium 360, and the disc key decryption unit 370 included in the recording apparatus 300 illustrated in FIG. 3.

[50] Referring to FIG. 4, the local storage unit 440 downloads an encrypted title key and encrypted content from the server 401 or a database (not shown), and stores them. Referring to FIG. 4, the local storage unit 440 stores the encrypted title key and content together with an encrypted first disc key, so that they belong to the same group. Each of groups stored in the local storage unit 440 is managed using a content identifier. That is, the local storage unit 440 manages the groups by allocating content identifiers thereto in order to identify encrypted content belonging to each of the groups.

[51] The disc comparison unit 480 compares an encrypted second disc key extracted from a second disc loaded into the content recording apparatus 400 by the key extraction unit 470 with the encrypted first disc key stored in the local storage unit 440 in order to determine whether the disc keys are the same, and provides the result of comparing to the controller 420.

[52] The controller 420 controls the overall operation of the content recording apparatus

400 in order to perform a content recording method according to the present invention. The controller 420 controls the disc key decryption unit 470 to extract an encrypted first disc key from a first disc loaded into the content recording apparatus 400. The controller 420 transmits the first disc key to the server 401 via the communication unit 430, and downloads an encrypted title key obtained by encrypting the title key of the content with the first disc key, from the server 401. The controller 420 stores the downloaded, encrypted title key and scrambled content in the local storage unit 440 together with the encrypted first disc key, so that they belong to the same group.

[53] Thereafter, when the controller 420 receives a command that encrypted content and title key belonging to a specific group (which is managed with a specific content identifier) stored in the local storage unit 440 be recorded on the second disc loaded into the content recording apparatus 400, from a user via the user interface 410, then the controller 420 determines whether the loaded second disc is identical to the first disc. To this end, before recording scrambled content and a title key encoded using the first disc key, which are stored in the local storage unit 440, on the second disc, the controller 420 determines whether the second disc is identical to the first disc by extracting an encrypted first disc key stored in the local storage unit 440 to belong to the same group as the scrambled content and encrypted title key and then comparing it with the encrypted second disc key stored in the currently loaded second disc. That is, the controller 420 controls the disc key decryption unit 470 to extract the encrypted second disc key from the loaded second disc and to transmit the encrypted second disc key to the disc comparison unit 480. The controller 420 controls the disc comparison unit 480 to compare the encrypted first disc key stored in the local storage unit 440 with the second disc key in order to determine these disc keys are the same. If the encrypted first disc key is not the same as the encrypted second disc key, the controller 420 determines that the first disc is not identical to the second disc, and then controls the output unit to output an image indicating that the content and the encrypted title key cannot be recorded on the second disc concurrently with controlling the recording unit 450 not to record the encrypted content and first title key on the second disc. If the encrypted first disc key and the encrypted second disc key are the same, the controller 420 determines that the first disc and the second disc are the same, and then controls the recording unit 450 to record the encrypted content and first title key on the second disc.

[54] FIG. 5 is a block diagram illustrating the module construction of a server 301 that performs a content providing method according to an embodiment of the present invention. Referring to FIG. 5, the server 301 includes a transceiving processing module 541 that processes a communication with the recording apparatus 300 illustrated in FIG. 3; an encrypted title key generation module 543 that generates an encrypted title key by encrypting a title key of a desired title with a first disc key received from a user; and a title key comparing module 545 that determines whether the result of decoding a title key encrypted using a second disc key, which is received from the recording apparatus 300, is identical to a title key of content.

[55] The server 301 may use various operating systems (OSs) as an OS of the system. The

OS provides a high-level command to an application program interface (API) 501 in order to control the operation of an application module 540. The server 301 includes a high-level command processor 510 that identifies a corresponding element of the application module 540 according to the high-level command from the API 501, decodes the high-level command, and provides the result of decoding to the identified element. The application module controller 520 controls the operation of the application module 540 according to a command received from the high-level command processor 510. That is, the high-level command processor 510 determines whether an element corresponding to the high-level command from the API 501 is present in the application module 540 according to the high-level command from the API 501. Then, when the corresponding element is present, the high-level command processor 510 decodes the command into a command that the corresponding element can recognize, and either transmits the result of decoding to a related mapping unit or controls message transmission. Thus, the application module controller 520 includes a plurality of mapping units 521, 525, and 529 and a plurality of interface units 523, 527, and 531 related to the transceiving processing module 541, the encrypted title key generation module 543, and the title key comparing module 545.

[56] The transceiving processing module mapping unit 521 receives a high-level command for communicating with the recording apparatus 300 illustrated in FIG. 3 from the high-level command processor 510, maps the command to a device level command that the transceiving processing module 541 can process, and then provides the device-level command to the transceiving processing module 541 via the transceiving processing module interface unit 523.

[57] The encrypted title key generation module mapping unit 525 and the encrypted title key generation module interface unit 527 search for content that a user requests, extract a title key of the requested content, and generate an encrypted title key by encrypting the title key with a first disc key received from the recording apparatus 300. The encrypted title key generation module mapping unit 525 receives a high-level command for using the encrypted title key generation module 543 from the high-level command processor 510, maps the command to a device-level command, and then provides the device-level command to the encrypted title key generation module 543 via the encrypted title key generation module interface unit 527.

[58] The title key comparing module mapping unit 529 and the title key comparing module interface unit 531 receive the result of decoding a title key, which was encrypted with the first disc key, using a second disc key from the recording apparatus

300, together with a content identifier, and then compare the result of decoding with a title key of content identified using the content identifier in order to determine whether the result of decoding and the title key are the same. To this end, the title key comparing module mapping unit 529 receives a high-level command via the high-level command processor 510 and maps the command to a device-level command that the title key comparing module 545 can recognize. The device-level command is provided to the title key comparing module 545 via the title key comparing module interface unit 531.

[59] FIG. 6 is a flowchart illustrating a content recording method performed by the recording apparatus 300 of FIG. 3, according to an embodiment of the present invention. Referring to FIG. 6, the recording apparatus 300 extracts an encrypted first disc key from a first disc loaded into the recording apparatus 300, and obtains a first disc key by decoding the encrypted first disc key with a unique player key of the recording apparatus 300. The recording apparatus 300 transmits the first disc key to the server 301 via the communication unit 330 (operation 601). A user can select and download content to be recorded on the storage medium 360 by accessing the server

301. The server 301 generates an encrypted title key by encrypting the selected content with the first disc key. The recording apparatus 300 receives the encrypted title key from the server 301 (operation 603). The recording apparatus 300 stores the encrypted title key together with the encrypted content (operation 605). Upon receiving a command that the encrypted title key and the encrypted content be recorded on a currently loaded second disc from a user (operation 607), the recording apparatus 300 extracts a second disc key from the second disc and decodes the encrypted title key with the second disc key (operation 609). The recording apparatus 300 transmits the result of decoding to the server 301 (operation 611). The server 301 compares the result of decoding received from the recording apparatus 300 with the title key of the content in order to determine whether they are the same and then provides the result of determining to the recording apparatus 300. When it is determined that the result of decoding is identical to the title key (operation 613), the recording apparatus 300 records the title key encrypted with the first disc key together with the encrypted content on the second disc (operation 615). When it is determined that the result of decoding is not identical to the title key (operation 613), the recording apparatus 300 prevents the encrypted title key and the encrypted content from being recorded on the second disc, and creates and outputs an image indicating that the encrypted title key and the encrypted content cannot be recorded on the second disc (operation 617).

[60] FIG. 7 is a flowchart illustrating a content recording method performed by the content recording apparatus 400 of FIG. 4, according to another embodiment of the present invention. Referring to FIG. 7, the content recording apparatus 400 extracts an encrypted first disc key from a first disc loaded into the content recording apparatus 400 (operation 701). The content recording apparatus 400 obtains a first disc key by decoding the encrypted first disc key with a unique player key of the content recording apparatus 400, and transmits the first disc key to the server 401 (operation 703). The server 401 generates an encrypted title key by encoding desired content with the first disc key, and transmits it to the content recording apparatus 400. The content recording apparatus 400 receives the encrypted title key from the server 401 (operation 705). The content recording apparatus 400 stores the encrypted title key to belong to the same group as the encrypted content and the encrypted first disc key, where the group is identified by a content identifier (operation 707). Upon receiving a command that an encrypted title key and encrypted content belonging to a group identified by a specific content identifier be recorded on a second disc loaded thereinto, from a user (operation 709), the content recording apparatus 400 extracts the encrypted second disc key from the second disc (operation 711). The content recording apparatus 400 searches the local storage unit 440 for the group identified by the specific content identifier, and extracts an encrypted first disc key belonging to the group. The content recording apparatus 400 determines whether the extracted first disc key is identical to a second disc key (operation 713). If the extracted first disc key is identical to the second disc key, the content recording apparatus 400 determines that the first disc and the second disc are the same, and then records the encrypted title key and the encrypted content on the second disc (operation 715). If the extracted first disc key is not identical to the second disc key, the content recording apparatus 400 prevents the encrypted title key and the encrypted content from being recorded on the second disc, and creates and outputs an image indicating that the encrypted title key and the encrypted content cannot be recorded on the second disc (operation 717).

[61] FIG. 8 is a flowchart illustrating a content providing method performed by the server

301 of FIG. 3, according to an embodiment of the present invention. Referring to FIG. 8, the server 301 receives a first disc key from the recording apparatus 300 (operation 801). As described above, the server 301 stores various types of content scrambled with respective title keys, and the titles keys for respectively decoding the scrambled content. A user can select desired select from the server 301. The server 301 searches for the selected content, and extracts a title key of the selected content. The server 301 generates an encrypted title key by encoding the extracted title key with the first disc key (operation 803), and transmits it to the content recording apparatus 300 (operation 805). Then, the server 301 receives the result of the encrypted title key with a second disc key from the content recording apparatus 300, together with a content identifier (operation 807). The server 301 searches for content identified by the content identifier, and extracts a title key of the content. The server 301 compares the extracted title key with the result of decoding received from the recording apparatus 300 in order to determine whether they are the same (operation 809). The server 301 provides the result of determining to the recording apparatus 300 (operation 811).

[62] The present invention can be embodied as computer readable code in a computer readable medium. Here, the computer readable medium may be any recording apparatus capable of storing data that is read by a computer system, e.g., a read-only memory (ROM), a random access memory (RAM), a compact disc (CD)-ROM, a magnetic tape, a floppy disk, an optical data storage device, and so on. Also, the computer readable medium may be a carrier wave that transmits data via the Internet, for example. The computer readable medium can be distributed among computer systems that are interconnected through a network, and the present invention may be stored and implemented as computer readable code in the distributed system. A function program, code and code segments for embodying the present invention may be easily derived by computer programmers skilled in the art to which the present invention pertains.

[63] While this invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims

[1] L A content recording method which is performed by a recording apparatus communicating with a server via a communication network, the method comprising: transmitting a first disc key of a first disc loaded into the recording apparatus to the server; receiving, from the server, an encrypted title key obtained by encrypting a title key of content by using the first disc key; determining whether a second disc key of a second disc loaded into the recording apparatus is identical to the first disc key; and if the second disc key is identical to the first disc key, recording the content and the encrypted title key on the second disc.

[2] 2. The method of claim 1, wherein the determining of whether the second disc key is identical to the first disc key comprises: decrypting the encrypted title key with second disc key; transmitting the result of decrypting to the server, together with a content identifier identifying the content; and receiving, from the server, the result of determining whether the result of decrypting is identical to the title key of the content identified by the content identifier.

[3] 3. The method of claim 2, further comprising: obtaining the first disc key by decrypting an encrypted first disc key recorded on the first disc by using a player key of the recording apparatus; and obtaining the second disc key by decrypting an encrypted second disc key recorded on the second disc by using the player key of the recording apparatus.

[4] 4. The method of claim 2, wherein the recording of the content and the encrypted title key on the second disc comprises determining that the second disc is identical to the first disc when the recording apparatus receives, from the server, the result of determining that the result of decrypting is identical to the title key of the content.

[5] 5. The method of claim 4, when the recording apparatus receives, from the server, the result of determining that the result of decrypting is not identical to the title key of the content, further comprising creating and outputting an image indicating that recording of the content and the encrypted title key on the second disc is not allowed.

[6] 6. The method of claim 1, wherein the determining of whether the second disc key is identical to the first disc key is performed based on whether an encrypted second disc key extracted from the second disc is identical to an encrypted first disc key extracted from the first disc.

[7] 7. The method of claim 6, further comprising storing the encrypted title key received from the server, together with the content and the encrypted first disc key, so that the encrypted title key, the content and the encrypted first disc key belong to the same group, wherein the recording of the content and the encrypted title key on the second disc comprises: receiving a command that the content and the encrypted title key are to be recorded on the second disc; extracting the stored encrypted first disc key belonging to the same group with the content and the encrypted title key, in response to the command; extracting the encrypted second disc key from the second disc; and determining whether the encrypted first disc key is identical to the encrypted second disc key.

[8] 8. The method of claim 7, if the encrypted first disc key is not identical to the encrypted second disc key, further comprising creating and outputting an image indicating that recording of the content and the encrypted title key on the second disc is not allowed.

[9] 9. A content providing method which is performed by a server communicating with a recording apparatus via a communication network, the method comprising: receiving a first disc key of a first disc from the recording apparatus; generating an encrypted title key by encrypting a title key of content with the first disc key; transmitting the encrypted title key to the recording apparatus; receiving, from the recording apparatus, a result of decrypting the encrypted title key with a second disc key of a second disc; determining whether the result of decrypting received from the recording apparatus is identical to the title key of the content; and providing the result of determining to the recording apparatus.

[10] 10. The method of claim 9, further comprising receiving a content identifier identifying the content from the recording apparatus, wherein the determining of whether the result of decrypting is identical to the title key of the content comprises: extracting the title key of the content identified by the content identifier; and determining whether the result of decrypting received from the recording apparatus is identical to the extracted title key.

[11] 11. A content recording apparatus communicating with a server via a communication network, the apparatus comprising: a communication unit exchanging information with the server via the communication network; a disc key decryption unit extracting a first disc key from a first disc loaded into the recording apparatus; a controller controlling the apparatus to transmit the extracted first disc key to the server and receive an encrypted title key obtained by encrypting a title key of content by using the first disc key, from the server; determining whether a second disc key of a second disc loaded into the recording apparatus is identical to the first disc key; and allowing the content and the encrypted title key to be recorded on the second disc if the second disc key is identical to the first disc key; and a recording unit recording the content and the encrypted title key on the second disc.

[12] 12. The apparatus of claim 11, further comprising a title key decryption unit decrypting the encrypted title key with the second disc key of the second disc, wherein the disc key decryption unit extracts the second disc key from the second key loaded into the recording apparatus, and the controller allows the result of decrypting received from the title key decryption unit to be transmitted to the server, together with a content identifier identifying the content, and is informed of whether the result of decrypting is identical to the title key of the content identified by the content identifier, which is received from the server.

[13] 13. The apparatus of claim 11, wherein the disc key decryption unit extracts an encrypted first disc key from the first disc, obtains the first disc key by decrypting the encrypted first disc key with a player key of the apparatus, extracts an encrypted second disc key from the second disc, and obtains the second disc key by decrypting the encrypted second disc key with the player key.

[14] 14. The apparatus of claim 12, wherein if the controller is informed from the server that the result of decrypting is identical to the title key of the content, the controller determines that the second disc is identical to the first disc.

[15] 15. The apparatus of claim 14, further comprising an output unit outputting the content recorded on the disc, wherein if the controller is informed from the server that the result of decrypting is not identical to the title key of the content, the controller controls the output unit to create and output an image indicating that recording of the content and the encrypted title key on the second disc is not allowed.

[16] 16. The apparatus of claim 11, wherein the disc key decryption unit extracts an encrypted second disc key from the second disc and an encrypted first disc key from the first disc, and the controller determines whether the second disc is identical to the first disc, based on whether the encrypted first disc key is identical to the encrypted second disc key.

[17] 17. The apparatus of claim 16, further comprising: a local storage unit storing the encrypted title key received from the server, together with the content and the encrypted first disc key, so that the encrypted title key, the content, and the encrypted first disc key belong to the same group; and a disc comparison unit determining whether the encrypted first disc key is identical to the encrypted second disc key.

[18] 18. The apparatus of claim 17, further comprising an output unit outputting the content recorded on the disc, wherein if the encrypted first disc key is not identical to the encrypted second disc key, the controller controls the output unit to create and output an image indicating that recording of the content and the encrypted title key on the second disc is not allowed.

[19] 19. A server for communicating with a recording apparatus via a communication network, the server comprising: a transceiving unit exchanging information with the recording apparatus via the communication network; an encrypted title key generation unit generating an encrypted title key by encrypting a title key of content with a first disc key of a first disc, where the first disc key is received from the recording apparatus; a title key comparison unit determining whether the result of decrypting the encrypted title key with a second disc key of a second disc is identical to the title key of the content, where the result of decrypting is received from the recording apparatus; and a controller controlling the server to generate the encrypted title key, determine whether the result of decrypting is identical to the title key of the content, and provides the result of determining to the recording apparatus.

[20] 20. The server of claim 19, wherein the title key comparison unit extracts the title key of the content by using a content identifier identifying the content, where the content identifier is received from the recording apparatus, together with the result of decrypting.

[21] 21. A computer readable having recorded thereon a computer program for executing a content recording method which is performed by a recording apparatus communicating with a server via a communication network, the method comprising: transmitting a first disc key of a first disc loaded into the recording apparatus to the server; receiving, from the server, an encrypted title key obtained by encrypting a title key of content by using the first disc key; determining whether a second disc key of a second disc loaded into the recording apparatus is identical to the first disc key; and if the second disc key is identical to the first disc key, recording the content and the encrypted title key on the second disc. [22] 22. A computer readable having recorded thereon a computer program for executing a content providing method which is performed by a server communicating with a recording apparatus via a communication network, the method comprising: receiving a first disc key of a first disc from the recording apparatus; generating an encrypted title key by encrypting a title key of content with the first disc key; transmitting the encrypted title key to the recording apparatus; receiving, from the recording apparatus, the result of decrypting the encrypted title key with a second disc key of a second disc; determining whether the result of decrypting received from the recording apparatus is identical to the title key of the content; and providing the result of determining to the recording apparatus.