CN1985320A - Combining DRM data and UDF on optical media - Google Patents

Abstract

This invention relates to a device for an optical carrier. The device is equipped with a local storage device and a control unit. The control unit controls the storage of a dataset last written to the optical carrier in the storage device. The control unit then triggers the writing of digital access control (DRM) data to a disk and writes the dataset temporarily stored in the local storage device back to the disk. If the dataset is an information control block associated with the disk's virtual allocation table, the carrier meets specific UDF specifications and requirements for certain DRM-related standards (e.g., the Sapphire scheme).

Description

Combine DRM data and UDF on optical media

technical field

The invention belongs to the field of optical storage in which record carriers have a main program storage area. The present invention relates to integrating the security mechanism into the optical disc, and more specifically relates to the specification of writing digital rights management data in the main program storage area.

Background technique

A generic file structure for writable optical storage media is specified in the Universal Disk Format (UDF) standard. The generic file system imposes various conditions on file location and operational read/write processing. Among these conditions, the UDF sets the order of some files that must be written. For example, the UDF standard stipulates that for an open CD-R, the last written sector must be the Information Control Block (ICB) of the Virtual Allocation Table (VAT). While this requirement sounds straightforward to implement, it is not a good policy. Exactly meeting this requirement is critical to the installation process, as failure to find the ICB where it should be will cause a read error and fail the operation.

In addition to the requirements set forth above by common file system standards, the electronics industry seeks to integrate technical security mechanisms to ensure that loss of content is prevented and that usage of valid content can be closely monitored and restricted. There is therefore a strong push by the industry and content providers for the pervasive integration of digital rights management data in optical discs. To this end, solutions are being discussed in industry associations and standards are being drafted. Most schemes define stringent conditions that need to be met to ensure industry interoperability. One of these schemes is called the Sapphire specification. The Sapphire scheme describes keys and rights about protected content on a disc, and these keys and rights are stored securely in a so-called Key Locker Area (KLA) in the program area or in the lead-in part of the disc. One of these specifications is written in the KLA immediately before the VAT-related ICB. VAT is only used if the type of access to the disc is sequential, and thus unavoidable in CD-R and optional in CD-RW. The entry point of the DRM data is contained in the DRM pointer entry, especially in the Adaptation Layer Parameter Space (ALP), where the physical locations of all key locker copies are listed, the key locker ( locker) is a structure containing permissions and keys for protected data. KLA is an area on the disc reserved for the key locker and ALP. For a recordable (write once) access type disc, DRM data can be placed anywhere in the program area, and a DRM pointer entry can be placed anywhere after the DRM data. A method of finding DRM data stored on a disc is disclosed in European Patent Application No. 2004/021345 A1, which is hereby incorporated by reference. This document discloses a method of accessing digital rights management data stored in the program area of a record carrier as a recordable or rewritable disc. The proposed solution adds an entry in the disc to allow the drive to find the DRM pointer entry (ALP), which points to the DRM data stored on the disc.

However writing the KLA at a different location than specified in the Sapphire scheme can delay the reading of the disc and playback of the content. In fact, if the KLA cannot be easily found at a prescribed location next to the ICB, the drive's operating system first needs to scan the entire disc before processing the stored content and this scan may take minutes or hours.

As mentioned above, the UDF standard imposes a condition on the location of the ICB on the disc, and the current standardization work tends to impose a condition on the location of the KLA. So both requirements need to be fulfilled at the same time. When reading, this arrangement works well because the ICB will be located at the last written sector of the program area, and the KLA will be placed nearby. The problem arises when writing to KLA. In fact, in host/drive optics, when using common UDF support, both the host and the drive are responsible for writing the data, but neither takes full control. There is therefore a need to define a write mechanism that will satisfy the UDF standard and the Sapphire specification or any other specification that will place the same restrictions on DRM data, without affecting the general structure of the disc.

Contents of the invention

It is therefore an object of the present invention to provide a solution that satisfies not only the Universal File System defined in UDF but also any standard that imposes conditions on DRM-related data.

The principle of the present invention is to integrate usage restrictions on content stored on conventional optical recordable discs.

To this end, a method for storing data on a record carrier of the type defined above is proposed. The method includes a first step in which the data set last written to the main program memory area of the disc is stored in the memory of the drive. Then, write digital rights management data in the main program storage area. DRM data enables the control of access to protected content stored on the record carrier. When the DRM data is written to the disc, the data sets stored in the drive memory are sequentially written back into the main program storage area following the DRM data.

The present invention proposes to temporarily store the last written sector in the drive memory, while at the same time the data relating to digital rights management is written to the disc. The data temporarily stored in the memory is then written back onto the disc next to the DRM data. Therefore, the present invention advantageously solves the problem currently under discussion if the data temporarily stored in the drive memory is an ICB. In fact, if the carrier is UDF compatible, the last sector written will actually contain the ICB and Virtual Allocation Table. The present invention therefore ensures that the ICB is the last sector written to the disc and that the DRM data is written sequentially next to it.

In an exemplary embodiment of the invention, said method is performed when a request is made to write DRM data onto said carrier. Such a request may be subordinate to other commands, such as an eject command, a close command, or may be generated according to the necessity to update the DRM data. For example, a system may be set up such that DRM data is automatically updated if updates have been pending in the drive for a predetermined time period, or when the number of pending updates is above a limit. Writing of DRM data can also be triggered by the drive being turned off or ejecting the carrier from the drive.

The invention also relates to a drive device having a receptacle into which a record carrier can be inserted. The record carrier may be an optical disc with a UDF defined structure comprising a lead-in memory area, a main program memory area and a lead-out memory area. The device also comprises a storage means and control means adapted to control the writing of data on the record carrier. The device of the present invention causes said control means to control storing in said storage means a data set last written into said main program storage area. The control device then controls to write data related to digital rights management in the main program storage area. This data defines the rules regarding access to content on the record carrier. The control device further controls to write the data set stored in the storage device into the main program storage area.

These and other aspects of the invention will be apparent from and will be elucidated with reference to the embodiments described hereinafter.

Description of drawings

The invention will now be described in more detail by way of example with reference to the accompanying drawings, in which:

Fig. 1 is the carrier/driver system of the present invention;

Figures 2a, 2b and 2c show the layout of the carrier of the invention.

Detailed ways

Figure 1 shows a block diagram of a reproduction system 100 according to the invention. In order to read user data from the disc 102, a reading unit 104 is provided. There is widespread consensus among content providers and industry players to develop digital rights management (DRM) systems that define usage restrictions on some or all user data. This means that the content stored on the disc 102 may be encrypted, and the disc 102 may store an encryption key for decrypting the content before the user can process the content. Additionally, usage rights may be stored on disc 102, eg indicating whether making copies of the content is permitted. Such usage rights and keys will be referred to as DRM data. The reading unit 104 is further arranged for reading such DRM data. However, first a pointer to the DRM data needs to be found, and the reading unit 104 is provided with an evaluation unit for that effect. Once the evaluation unit in the reading unit 104 has determined the position of the DRM pointer, the DRM data is provided to the control block 114 via the wire 206 . A control block 114 resides within a digital signal processing unit (DSP) 110 which is responsible for processing the content and format specific data on the disc 102 when writing to or playing back content from the disc 102 . The read DRM data is used to control the output of the user data, that is, the control unit 114 controls the content playout unit 112 of the DSP 110, for example, by prohibiting the output of the output signal OUT if the use authority forbids the output, or by playing out the data Data decryption is enabled before being given to the user. The invention is not limited only to the usage rights and key encryption mechanisms described above, and thus also includes other usage restrictions or any other type of control regarding content access or handling.

The reproduction system 100 of FIG. 1 can accept a writable disc, and also includes a writing unit 108 for writing content on the disc 102 . Disc 102 is a CD-R based on the Orange Book Part II specification, ie disc 102 is write once, however the general principles of the invention are also applicable to rewritable discs or other types of optical storage media. For example, the invention may also relate to the upcoming Blu-ray discs, specifically BD-R and DVD+R/-R.

The data IN supplied to the input of the DSP unit 110 is transferred to the writing unit 108 via the wire 204 . The DSP 100 can control how the writing unit 108 performs writing of the data IN onto the disk 102 via the control line 202. The DSP 100 can also control the writing of data obtained by the storage device 106 of the system 100 to the disk 102, which will be described later.

The reproduction system is also equipped with storage means 106 for storing content, user data and format specific data related to the disc 102 . Storage device 106 may include a temporary memory portion for storing data sets that have a short lifetime (ie, data sets that may be processed after a read or write cycle or when an inserted disc 102 is ejected). The storage device 106 may also include a permanent storage portion for permanent storage of user and standard specific data and content, whether erasable or non-erasable.

In the exemplary embodiment, system 100 is UDF and Sapphire compatible. Thus, system 100 and disk 102 meet the previously mentioned requirements. Therefore, to ensure that the ICB block is within the last written sector and that the KLA is next to the ICB, the system 100 operates as follows.

The system 100 can be designed to automatically trigger the writing of KLA data under certain circumstances. Writing to the KLA can be initiated in two ways. In a first scenario, the application responsible for writing content on disc 102 sends a command to write KLA to writing unit 108 . The application may run within DSP 110 or external to system 100. The write command may be part of the writing process, such as terminating any writing of content on disc 102 . Therefore, whenever the DSP 110 controls the writing of data sets protected by the associated DRM rights, the final write process will be accompanied by a command to write the KLA data representing the DRM rights. The KLA data may be received along with the content to be written on the disc 102 or may have been previously stored in and obtained from the storage device 106 . DSP 110 may also issue a write command when a pending update of the KLA data temporarily stored in storage device 106 has been postponed for too long. Updates of the KLA on disk 102 may also occur at regular intervals.

Alternatively, the KLA data is written when the disk 102 is ejected from the system 100 . DSP 110 keeps track of whether the KLA cached in storage device 106 has changed. KLA is changed when writing content or when unit 104 reads content from disk 102 . For example, the right to watch a movie may limit the user to a maximum number of viewings. Therefore, the KLA data related to the movie is cached and updated in the storage device 106 when viewing the content. The above is just one example, the invention also relates to systems where reads do not have to be accompanied by KLA changes. Finally, when ejecting the disk 102 or turning off the power of the system 100 in response to an external command COM, the system DSP 110 checks whether an update of the KLA data is pending in the device 106 and modifies the disk 102 accordingly before ejecting the disk 102 or before shutting down KLA on.

Writing or updating the KLA can be initiated under the specific circumstances described above, however the present invention encompasses any other circumstances not described here that can result in writing to the KLA.

Fig. 2a, Fig. 2b and Fig. 2c show the structural format of the disc 102 defined by the UDF standard at three times. The disc 102 includes a lead-in portion 402 , a main program storage area 404 and a lead-out portion 406 . The lead-in and lead-out sections are reserved areas on the disc 102 and have not been written to yet. In FIG. 2 a , writing unit 108 has written data set 408 in the main program area of disc 102 . System 100 is UDF compatible, and thus when writing the data set onto disc 102, write unit 108 will then write the associated VAT ICB in the main program storage area of disc 102. In subsequent operations, a request is made to write the KLA onto disk 102 in one of the situations described above. DSP 110 then controls read unit 104 to copy the last written data block from disk 102 into storage device 106. At this moment, as represented in Figure 2a, the last written block is VAT ICB. Then, DSP 110 controls KLA to be written on the disc 102, as shown in Figure 2b, and in the next step thereafter, control writes the cache VAT ICB from memory 106 into the program storage area of disc 102. Finally, the structure of the disc 102 is shown in Figure 2c, and the last written sector is still VAT ICB, and the DRM data contained in the KLA is stored next to VAT ICB in the program area. It is therefore an advantage of one or more embodiments to enable fast retrieval of DRM pointers and data contained in the KLA while complying with the UDF standard. The present invention allows digital rights management to be added to the optical disc without changing the common parts of the software and hardware of the system 100, and the present invention only needs to change the optical drive.

Claims (10)

1. A method for storing data on a record carrier (102) comprising a main program storage area (404), said method comprising: storing in the drive's memory (106) the data set last written to the main program storage area of the disc; writing digital rights administration data (KLA) in said main program storage area for controlling access to content on the record carrier; and The data set stored in the drive memory is written to the main program memory area next to the digital rights management data. 2. The method of claim 1, wherein said storing and writing steps are performed in response to a request from the drive to write digital rights management data. 3. The method of claim 2, wherein the request is triggered by an eject command that ejects the disc from the drive. 4. The method of claim 2, wherein said request is triggered when the number of pending updates of digital rights management data is above a threshold. 5. The method of claim 2, wherein the request is triggered based on a duration that an update is pending. 6. The method of claim 1, wherein storing the data set in the drive memory is performed concurrently with writing the data set to the program storage area of the disc. 7. The method of claim 1, wherein the step of storing the data set in drive memory comprises copying the data set from a main program memory area. 8. The method of claim 1, wherein said data set is a control block of information associated with a virtual allocation table stored to disk. 9. The method of claim 1, wherein the digital rights management data is stored in a key locker area as defined in the Sapphire specification. 10. An apparatus comprising: a receiver for receiving a record carrier comprising a main program storage area; storage device; control means (108, 110) adapted to control the writing of data onto the record carrier; It is characterized by: The control device controls to store in the storage device (106) the data set that is written into the main program storage area at last, and the data set is written in the main program storage area afterward and related to digital rights management. data related to digital rights management for controlling access to content on the record carrier (102); and the control means further controls writing of data sets stored in said storage means to said main program storage in the district.

Images