KR100513280B1 - System and Method for AV-data copy protection - Google Patents

Abstract

The present invention relates to AV data copy protection, and the AV data copy protection system according to the present invention includes an AV content area including first copy control information and an AV content area including second copy control information. A copy control information inspection unit which receives the first copy control information from data, transmits a control command corresponding to the first copy control information and the first copy control information, and the first copy control information according to the control command. And a key generator for generating a decryption key using predetermined decryption key generation information, and a decoder for decoding the AV data using the decryption key.

Description

System and Method for AV-data copy protection

The present invention relates to data copy protection, and more particularly, copy control information included in audio / video streaming data (hereinafter referred to as 'AV data'). The present invention relates to a system for preventing illegal copying of contents included in AV data using Information (CCI) and a method for preventing illegal copying.

With the development of digital signal processing technology, various types of digital recording devices and recording media are widely used. However, the digital data contained in such a device and recording medium can be repeatedly reproduced and copied. Therefore, if a copying medium that is illegally copied is distributed to the market, the rights of the copyright holder or legitimate distributor of various contents such as music and movies can be obtained. This may be infringed. Recently, various methods have been introduced to prevent such illegal copying of digital data. Among them, there is a method using copy control information.

In general, AV data includes copy control information indicating a copy control status of content. The copy control information indicates whether a system that processes AV data, such as a recorder implemented by hardware or software, has a right to copy content contained in AV data received from a transmission medium. The devices determine whether to decode the content according to the value of the copy control information.

The copy control information may be represented by a predetermined bit in the AV data, and is generally represented by a 2-bit code, and it is possible to set four types of modes as shown in [Table 1]. . Looking at the modes that can be configured as the copy control information in more detail [Table 1].

FIG. 1 is an exemplary view illustrating a schematic structure of AV data, and the AV data 100 includes an information field containing information of content and a content field containing content of the content.

The information field includes the copy control information area 110 used to control the copy operation of the device and information on various contents contained in the AV data. The content fields are 'Content_unit_1', ' It can be divided into n subunit areas such as 'Content_unit_2', ..., 'Content_unit_n'.

An area 110 of copy control information (hereinafter referred to as 'first copy control information') included in an information field is divided by the number of the sub units, and each divided area is configured for the sub units. It includes a copy control information value, such as '11', '10' and the position information indicating the position of the sub unit. In this case, the location information may be a physical or logical address for the sub unit or time information when the content in the sub unit is played. In FIG. 1, the location information is illustrated as 'unit_1_ptr', 'unit_2_ptr', ..., and 'unit_n_ptr'.

In addition, the sub unit may be divided into one or more areas. For example, the sub unit 'Content_unit_2' 120 in the content field may be divided into three subregions of 'Sub_2_1', 'Sub_2_2', and 'Sub_2_3', each of which has unique copy control information. 130 may be included.

Copy control information (hereinafter referred to as 'second copy control information') included in each sub-unit included in the contents field is mainly used to generate a decryption key for decoding the content. Cannot be decrypted. However, since the first copy control information 110 is used to control the operation of whether to copy the content, the third copy control information 110 enables illegal copying by changing the first copy control information 110.

2 is an exemplary view showing a conventional data copy protection system for preventing illegal copying of content.

The data copy protection system 200 for decrypting the encrypted AV data includes an AV data receiver 210, a controller 220, a decryption key generator 230, and a content interpreter 240. The AV data receiver 210 receives AV data. The controller 220 receives a control signal for controlling the operation of the apparatus for processing AV data from the outside, wherein the control signal may include a content reproduction command signal, a content copy command signal, and the like. The control unit 220 receives the first copy control information 110 shown in FIG. 1 from the AV data receiving unit 210, and transmits the first copying control information to the decryption key generation unit 230 and the content analyzing unit 240. A control signal corresponding to the copy control information 110 is sent.

When the decryption key generation unit 230 receives a decryption key generation command from the control unit 220, the decryption key generation unit 230 receives the second copy control information and other information for key generation from the AV data receiver 210 and generates a decryption key to interpret the contents. Transfer to section 240. The content analyzer 240 decodes the content field in the AV data received by the AV data receiver 210 using the decryption key received from the decryption key generator 230, and outputs the decoded content. Send to 250.

The operation of the conventional AV data processing system for decoding AV data is as follows.

The AV data receiving unit 210 receives the AV data and transmits the first copy control information 110 shown in FIG. 1 included in the AV data to the control unit 220.

The control unit 220 receives a device operation control signal from the outside. If the control signal is a content duplication command signal, the AV data received by the AV data receiving unit 210 from the first copy control information 110. Check the content encryption status.

At this time, if the first copy control information 110 is 'copy free', it is not necessary to generate a decryption key, so that the content analyzer 240 causes the AV data received by the AV data receiver 210 to remain as it is. To the output device 250.

If the first copy control information 110 is 'no more copy or copy never', 'copy free but encrypted' or 'copy one generation', it is necessary to decode it. Therefore, the decryption key generation unit 230 receives the first copy control information 110 from the control unit 220 and receives the second copy control information and other information for key generation from the AV data receiving unit 210. A decryption key is generated and transmitted to the content analyzer 240, and the content analyzer 240 decodes the content field in the AV data received by the AV data receiver 210 using the received decryption key. The decoded content is transmitted to the output device 250 corresponding to the storage medium or the display device.

In the conventional AV data copy protection system 200, the first copy control information is used to confirm the copy right of the content. There is a problem that the first copy control information can be easily modulated for the purpose of illegal copying. That is, in Table 1, 'no more copy or copy never (11)' or 'copy one generation (10)' is changed to 'copy free but encrypted (01)' or 'no more copy or copy never (11) ) 'Is changed to "copy one generation (10)" and is received by the AV data receiving unit 210, so that the control unit 220 incorrectly recognizes the AV data as the copying permission. Occurs.

The present invention has been made to solve the above problems, and in the present invention, when generating a key for encrypting or decrypting data, the first copy control information is utilized to decrypt content due to an illegal change of copy control information. Suggest ways to effectively prevent piracy.

In order to achieve the above object, the data copy protection system according to an embodiment of the present invention is the first from the AV data including the AV content information area including the first copy control information and the AV content area including the second copy control information. A copy control information inspection unit which receives copy control information and transmits a control command corresponding to the first copy control information and the first copy control information, and the first copy control information and predetermined decoding according to the control command. And a key generator for generating a decryption key using key generation information, and a decoder for decoding the AV data using the decryption key.

In order to achieve the above object, the data copy protection system according to an embodiment of the present invention is the first from the AV data including the AV content information area including the first copy control information and the AV content area including the second copy control information. A copy control information inspection unit which receives copy control information and transmits a control command corresponding to the first copy control information and the first copy control information, and the first copy control information and a predetermined cipher according to the control command. And a key generation unit for generating an encryption key using key generation information, and an encryption unit for encrypting the AV data using the encryption key.

In order to achieve the above object, the data copy protection method according to the embodiment of the present invention is the first from the AV data including the AV content information area including the first copy control information and the AV content area including the second copy control information; A first step of receiving copy control information, a second step of determining a copy control state of the first copy control information, and transmitting a control command corresponding to the copy control state and the first copy control information; A third step of generating a decryption key using the first copy control information and predetermined decryption key generation information according to the control command, and a fourth step of decoding the AV data using the decryption key.

In order to achieve the above object, the data copy protection method according to the embodiment of the present invention is the first from the AV data including the AV content information area including the first copy control information and the AV content area including the second copy control information; A first step of receiving copy control information, a second step of determining a copy control state of the first copy control information, and transmitting a control command corresponding to the copy control state and the first copy control information; And a third step of generating an encryption key using the first copy control information and predetermined encryption key generation information according to the control command, and a fourth step of encrypting the AV data using the encryption key.

In this case, preferably, the copy control information indicates a plurality of copy control state modes according to predetermined bit information. The mode is a first mode which never prohibits copying, and the content is encrypted and copying is possible only once. The second mode is changed to the first mode after copying, a third mode in which content is encrypted but can be copied without restriction, and a fourth mode in which content is not encrypted and can be copied without restriction. Also, preferably, the key generation information includes the second copy control information.

Hereinafter, a system (hereinafter referred to as a 'content protection system') and a copy protection method for AV data copy protection according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

On the other hand, the content protection system according to an embodiment of the present invention may extract the content from the AV data storage medium and play back, or may decrypt the encrypted content and store it in another storage medium such as a hard disk. In addition, the contents can be encrypted and recorded on the AV data storage medium. Therefore, the following description will be divided into a case where the content protection system encrypts and records the content and a case where the encrypted content is decrypted and copied.

3 is an exemplary diagram showing a block diagram for a content protection system according to an embodiment of the present invention to encrypt and record content to an AV data storage medium.

The content protection system 300 inspects the state of the first copy control information, the copy control information inspecting unit 310 for generating a control signal corresponding thereto, and a content processing unit for generating an encryption key and encrypting content according to the control signal. 320. The content protection system 300 operates in conjunction with a CPU memory 330 that receives AV data and a CPU 340 that processes AV data stored in the CPU memory 330.

Hereinafter, a process for encrypting content and recording the same on an AV data storage medium will be described.

When the AV data is loaded into the CPU memory 300, the CPU 340 includes the first copy control information 110 and the second copy control information 130 shown in FIG. 1 from the AV data. The key generation information and the content are extracted and transmitted to the content protection system 300.

The copy control information inspecting unit 310 receives a control signal for the operation mode of the content protection system 300 from the user 360, and at this time, the AV data received as the operation mode to the AV data storage medium 350. And a mode for encrypting and recording (hereinafter, referred to as 'first mode') and a mode for requesting decryption of the received AV data (hereinafter, referred to as 'second mode'). The embodiment shown in FIG. 3 shows operation in the first mode.

The copy control information inspecting unit 310 receives the first copy control information from the CPU memory 330 and inspects a copy control state. The copy control status is shown in [Table 1].

If the copy control state of the first copy control information is '11', content duplication is not allowed. Therefore, the copy control information inspecting unit 310 does not operate the key generating unit 322 of the content processing unit 320 so that the received AV data is not recorded in the AV data storage medium 350.

If the copy control state of the first copy control information is '00', it is not necessary to generate a key for encrypting the AV data since the copy of the content is free without encryption. Accordingly, the copy control information inspecting unit 310 allows the content processing unit 320 to record the received content to the AV data storage medium 350 without encryption. At this time, the first copy control information and the key generation information are also recorded.

If the copy control state of the first copy control information is '01' or '10', a key for encryption should be generated. Accordingly, the key generation unit 322 generates a key for encrypting the content using the key generation information received from the CPU memory 330 and the first copy control information received from the copy control information inspecting unit 310. In this case, the key generation information includes second copy control information, device information including the content protection system 300 in addition to the second copy control information, a common key or secret key value present in the device, and AV data. A common key or secret key according to the storage medium 350, and a seed value randomly generated for generating a key may be included.

When a key for encrypting content is generated by the key generator 322, the encryption / decryption unit 324 encrypts the content received from the CPU memory 330 using the key. Then, the encrypted content is recorded in the AV data storage medium 350.

4 is an exemplary diagram illustrating a block diagram for decrypting encrypted content by a content protection system according to an embodiment of the present invention.

The content protection system 400 inspects the state of the first copy control information, the copy control information inspecting unit 410 for generating a control signal corresponding thereto, and a content processing unit for generating a decryption key and decoding the content according to the control signal. 420. The content protection system 400 operates in conjunction with a CPU memory 430 for receiving AV data from the AV data storage medium 450 and a CPU 440 for processing AV data stored in the CPU memory 430.

Hereinafter, a process of decoding content using the content protection system 400 will be described.

When AV data is loaded into the CPU memory 400 from the AV data storage medium 450, the CPU 440 may copy the first copy control information 110 shown in FIG. 1 and the second copy from the AV data. The key generation information and the content including the control information 130 are extracted and transmitted to the content protection system 400.

The copy control information inspecting unit 410 receives a control signal for the operation mode of the content protection system 400 from the user 460, which shows that the copy control information inspecting unit 410 operates in the second mode.

The copy control information inspecting unit 410 receives the first copy control information from the CPU memory 430 and inspects a copy control state. The copy control status is shown in [Table 1].

If the copy control state of the first copy control information is '11', content duplication is not allowed. Therefore, the copy control information inspection unit 410 does not decode the key data generation unit 422 of the content processing unit 420 so that the received AV data is not decoded.

If the copy control state of the first copy control information is '00', it is not necessary to generate a key for decoding the AV data since the content is freely copied without being decoded. Therefore, the copy control information inspecting unit 410 outputs the content received by the content processing unit 420 as it is.

When the copy control state of the first copy control information is '01' or '10', a key for decoding should be generated. Therefore, the key generation unit 422 generates a key for decoding the content using the key generation information received from the CPU memory 430 and the first copy control information received from the copy control information inspecting unit 410. In this case, the key generation information includes second copy control information, device information including the content protection system 400 in addition to the second copy control information, a common key or secret key value present in the device, and AV data. A common key or secret key according to the storage medium 450, and a seed value generated randomly for generating a key may be included.

When a key for decoding content is generated by the key generator 422, the encryption / decryption unit 424 decodes and outputs the content received from the CPU memory 430 using the key.

In the above operation process, the AV data is loaded into the CPU memory 330 or the first copy control information is transferred from the CPU memory 330 to the copy control information inspecting unit 310. When copy control information is illegally tampered with and enters the copy control information inspecting unit 310, a key different from a key used to encrypt data stored in the AV data storage medium 450 may be generated. Therefore, the received AV data is not decoded.

5A to 5C are exemplary views illustrating a medium for providing AV data according to an exemplary embodiment of the present invention, wherein the CPU memory 430 receives the AV data through an interface unit 540 corresponding to the data transmission mediums 510, 520, and 530. can do.

FIG. 5A illustrates a wireless medium for WLAN, Bluetooth, wireless ATM, terrestrial or satellite communication according to the 802.11a or 802.11b standard.

Fig. 5B shows a wired medium indicating high speed serial communication such as Ethernet, FDDI, IEEE1394, or the like.

5C illustrates a storage medium representing an optical storage medium, a magnetic storage medium, a removable storage medium, and the like.

6 is a flowchart illustrating an embodiment of a process for preventing illegal copying of AV data according to an embodiment of the present invention.

Upon receiving the AV data (S605), the first copy control information is extracted from the AV data and the copy control state is checked (S610).

If the state of the first copy control information is '11' shown in [Table 1], the copying is prohibited since the copying process is terminated (S640).

If the state of the first copy control information is '00' shown in [Table 1], since the decoding is not necessary, the AV data received without outputting the decoding process is output as it is (S615).

If the state of the first copy control information is '01' or '10' shown in [Table 1], at least one copy is performed and thus the first copy control information is changed by a copy command (S620). A decryption key is generated using the generated key (S625). In this case, the decryption key includes second copy control information in addition to the first copy control information, and stores device information for copying AV data, a common key or secret key value existing in the device, or AV data. It may include a common key or a secret key according to the provided medium, a seed value generated randomly for generating a key.

After the decryption key is generated, the AV data received using the decryption key is decoded and output (S630 and S640).

The present invention described above is capable of various substitutions, modifications, and changes without departing from the spirit of the present invention for those skilled in the art to which the present invention pertains. It is not limited to drawing.

According to the present invention made as described above, all digital appliances and electronics used to provide a means for preventing illegal copying of contents due to the change of copy control information, and to store or reproduce AV data having copy control information. It can be easily applied to a product and can make a great contribution to content protection.

1 is an exemplary view showing a schematic structure of AV data.

2 is an exemplary view showing the configuration of a conventional data copy protection system for preventing illegal copying of content.

3 is an exemplary diagram showing a block diagram for encrypting content by a content protection system according to an embodiment of the present invention.

4 is an exemplary diagram illustrating a block diagram for decrypting encrypted content by a content protection system according to an embodiment of the present invention.

5A to 5C are exemplary views illustrating a medium for providing AV data according to an embodiment of the present invention.

6 is a flowchart illustrating an embodiment of a process for preventing illegal copying of AV data according to an embodiment of the present invention.

* Description of the symbols for the main parts of the drawings

400: content protection system

410: copy control information inspection unit

420: content processing unit

422: key generator

424 cancer / decryption unit

430: CPU memory

440: CPU

Claims (12)

Receiving the first copy control information from the AV data including the AV content information area including the first copy control information and the AV content area including the second copy control information, the control corresponding to the first copy control information. A copy control information inspecting unit which transmits a command and the first copy control information; A key generation unit generating a decryption key using the first copy control information and predetermined decryption key generation information according to the control command; And a decryption unit for decoding the AV data using the decryption key. The method of claim 1, The copy control information indicates a plurality of copy control state modes according to predetermined bit information. The mode is a first mode which never prohibits copying, and the content is encrypted and copying is possible only once. And a second mode in which the content is encrypted in a first mode, a third mode in which content is encrypted but without limitation, and a fourth mode in which content is not encrypted and without copy, without limitation. The method of claim 1, And the decryption key generation information includes the second copy control information. Receiving the first copy control information from the AV data including the AV content information area including the first copy control information and the AV content area including the second copy control information, the control corresponding to the first copy control information. A copy control information inspecting unit which transmits a command and the first copy control information; A key generation unit for generating an encryption key using the first copy control information and predetermined encryption key generation information according to the control command; And an encryption unit for encrypting the AV data using the encryption key. The method of claim 4, wherein The copy control information indicates a plurality of copy control state modes according to predetermined bit information. The mode is a first mode which never prohibits copying, and the content is encrypted and copying is possible only once. And a second mode in which the content is encrypted in a first mode, a third mode in which content is encrypted but without limitation, and a fourth mode in which content is not encrypted and without copy, without limitation. The method of claim 4, wherein And the encryption key generation information includes the second copy control information. A first step of receiving the first copy control information from AV data including an AV content information area including first copy control information and an AV content area including second copy control information; Determining a copy control state of the first copy control information and transferring a control command corresponding to the copy control state and the first copy control information; Generating a decryption key using the first copy control information and predetermined decryption key generation information according to the control command; And a fourth step of decoding the AV data using the decryption key. The method of claim 7, wherein The copy control information indicates a plurality of copy control state modes according to predetermined bit information. The mode is a first mode which never prohibits copying, and the content is encrypted and copying is possible only once. And a second mode in which the content is changed to the first mode, a third mode in which the contents are encrypted but without restriction, and a fourth mode in which the content is not encrypted and without duplication, without restriction. The method of claim 7, wherein And the decryption key generation information includes the second copy control information. A first step of receiving the first copy control information from AV data including an AV content information area including first copy control information and an AV content area including second copy control information; Determining a copy control state of the first copy control information and transferring a control command corresponding to the copy control state and the first copy control information; A third step of generating an encryption key using the first copy control information and predetermined encryption key generation information according to the control command; And a fourth step of encrypting the AV data using the encryption key. The method of claim 10, The copy control information indicates a plurality of copy control state modes according to predetermined bit information. The mode is a first mode which never prohibits copying, and the content is encrypted and copying is possible only once. And a second mode in which the content is changed to the first mode, a third mode in which the contents are encrypted but without restriction, and a fourth mode in which the content is not encrypted and without duplication, without restriction. The method of claim 10, And the encryption key generation information includes the second copy control information.