HK1069692B - Audio/video stream processing system and method for data copy protection - Google Patents

Description

Audio/video stream processing system and method for data copy protection

Technical Field

The system, apparatus and method of the present invention relate to protecting data, and more particularly, to preventing audio/video (AV) content from being illegally copied using Copy Control Information (CCI) contained in an AV stream.

Background

In general, an AV stream includes content and copy control information indicating a state of copy control of the content. That is, the copy control information indicates whether an AV stream processing system, e.g., a recording apparatus implemented by hardware or software, has authorization to copy contents contained in an AV stream received from a transmission medium. For example, the recording apparatus decrypts the content based on the value of the copy control information.

The copy control information may be represented by bits, for example, preset with a 2-bit code in the AV stream. Table 1 below lists four modes in which copy control information can be composed.

TABLE 1

Operation mode of AV device according to CCI information

Fig. 1 depicts a schematic structure of an AV stream 100. The AV stream 100 is composed of a content field containing content and an information field containing information related to the content. The information field includes an area 110 for copy control information, which is used to control a copy operation of the AV device, and information about various contents contained in the AV stream 100. The content field is divided into n subunit regions, namely "content _ unit _ 1", "content _ unit _ 2".

The area 110 for copy control information ("first copy control information") contained in the information field is divided into several areas corresponding to the number of sub-units. Each of the divided areas includes a copy control information value such as 00, 01, 10, and 11, and location information of a corresponding one of the sub-units. The location information may include a physical or logical address of the corresponding subunit, or time information related to when the content in the subunit is played. In fig. 1, "unit _ n _ ptr" represents position information, i.e., "unit _1_ ptr", "unit _2_ ptr", and.

The subunits may be divided into one or more regions. For example, one sub-unit included in the content field, i.e., "content _ unit _ 2", may be divided into three small areas, "sub-unit _2_ 1", "sub-unit _2_ 2", and "sub-unit _2_ 3", and each small area may include one corresponding copy control information 130.

The copy control information ("second copy control information") contained in each sub-unit of the content field is used to generate a decryption key to decrypt the content, and therefore, if it is modified, the content cannot be decrypted. For example, the copy control information 130 of subunit _2_1 is used to generate a decryption key to decrypt the content of subunit _2_ 1. However, the first copy control information 110 is used to control the copy operation, and since a third party can change the first copy control information 110, illegal copying of the content becomes possible.

Fig. 2 depicts a conventional AV stream data copy protection system for preventing contents from being copied without authorization of a content owner. The AV stream data copy protection system 200 that decrypts the encrypted AV stream data includes an AV stream receiving unit 210, a control unit 220, a decryption key generation unit 230, and a content interpretation unit 240. The AV stream receiving unit 210 receives AV stream data. The control unit 220 receives a control signal input from the outside to control the operation of the AV device. The control signal may include a command signal to play the content or a command signal to copy the content. Referring to fig. 1, the control unit 220 receives the first copy control information 110 transmitted from the AV stream receiving unit 210, and transmits a control signal corresponding to the value of the first copy control information 110 to the decryption key generating unit 230 and the content interpreting unit 240.

More specifically, the AV stream receiving unit 210 receives AV stream data, and transfers the first copy control information 110 in the AV stream data to the control unit 220. The control unit 220 receives a control signal from the outside to control the operation of the AV device. When the control signal is a command signal to copy the content, the control unit 220 checks the encryption status of the AV content in the AV stream data received by the AV stream receiving unit 210 with reference to the first copy control information 110.

When the value of the first copy control information 110 is "copy free", the decryption key does not need to be generated, and thus the control unit 220 allows the content interpretation unit 240 to transmit the AV stream data received by the AV stream reception unit 210 to the external device 250. When the value of the first copy control information 110 is "no more copy or never copy", "copy free but encrypted", or "copy once", the data needs to be decrypted. Accordingly, the decryption key generation unit 230 receives the first copy control information 110 from the control unit 220, generates a decryption key using the second copy control information 130 from the AV stream reception unit 210 and other information, and transmits the decryption key to the content interpretation unit 240. The content interpreting unit 240 decrypts the content field of the AV stream data received by the AV stream receiving unit 210 using the decryption key, and transfers the decrypted AV content to an output apparatus 250, such as a storage medium or a display device.

The conventional AV stream data copy protection system 200 checks whether the AV device has an authority to copy contents using the first copy control information 110. The first copy control information 110 can be easily modified to make the content illegally copied. For example, when "no more copy or never copy (11)" or "copy once (10)" is modified to "copy free but encrypted (01)", or when "no more copy or never copy (11)" is modified to "copy once (10)", and the above-described modified information is received by the AV stream receiving unit 210 of the conventional AV stream data copy protection system 200, the control unit 220 may erroneously confirm that the copying of the AV stream has been permitted. Illegal copying of the content can be achieved.

Disclosure of Invention

Accordingly, an aspect of the present invention provides an AV stream data processing system that prevents unauthorized processing of content by, for example, modifying copy control information.

Another aspect of the invention provides a method of protecting content that includes determining whether copy control information has been modified and responding appropriately to the modification.

Additional aspects and/or advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

To achieve the above and/or other aspects of the present invention, there is provided an audio/video (AV) stream processing system including: a reception unit receiving an AV stream, the AV stream including a content information field and a content field, wherein the content information field includes first copy control information, and the content field includes second copy control information; a determination unit that determines whether the first copy control information and the second copy control information are different; a decryption unit that processes the AV stream.

The determination unit may determine whether the copy control mode information of the first copy control information and the second copy control information is different.

When the first copy control information and the second copy control information are different, the decryption unit stops decrypting the contents of the AV stream.

When the first copy control information and the second copy control information are different, the decryption unit stops generating a decryption key for decrypting the contents of the AV stream.

Wherein when the first copy control information and the second copy control information are different, the decryption unit processes the content of the AV stream according to the copy control information having a higher priority in both the first copy control information and the second copy control information. The decryption unit may establish a priority between the first copy control information and the second copy control information. When the first copy control information and the second copy control information are different, the second copy control information may have priority over the first copy control information. When the first copy control information and the second copy control information are different, the first copy control information may have priority over the second copy control information. When one of the first copy control information and the second copy control information has enhanced copy control protection, it may have a higher priority.

Each of the first copy control information and the second copy control information may include a copy control mode of the AV stream content, the copy control mode may include a first mode, the content is encrypted and the permission of the copying is absolutely prohibited; a second mode in which the contents are encrypted and one-time copy is permitted, wherein the second mode is changed to the first mode after one-time copy; a third mode, content encryption and allowing unlimited copying; in the fourth mode, the content is not encrypted and unlimited copying is allowed.

The decryption unit may include: a key generation unit that generates a decryption key for decrypting the content; a content interpretation unit decrypting the content using the decryption key; and a control unit which controls the key generation unit and the content interpretation unit to stop generating the decryption key or to stop decrypting the content when the first copy control information and the second copy control information are different, and controls the key generation unit and the content interpretation unit according to the copy control mode when the first copy control information and the second copy control information are the same. When the first copy control information and the second copy control information are different, or the copy control mode corresponds to the first mode, generation of the decryption key or decryption of the content may be stopped in order to prevent unauthorized copying of the content. The key generation unit may generate the decryption key using information including the second copy control information. The control unit may control the key generation unit to generate a decryption key for decrypting the content in response to one of a second mode and a third mode of the copy control mode, and control the content interpretation unit to output the content in response to a fourth mode of the copy control mode.

The system may further include a storage unit that stores the decrypted content or the undecrypted content.

The system may further include a display unit that displays the decrypted content or the undecrypted content.

The determination unit may include: a storage unit that stores first copy control information; and a comparing unit comparing the copy control pattern of the first copy control information with the copy control pattern of the second copy control information.

The decryption unit may include: a control unit outputting a signal corresponding to a copy control mode when the first copy control information and the second copy control information are the same, generating a stop signal when the first copy control information and the second copy control information are different or the signal corresponds to the first mode, wherein the control unit outputs the stop signal to the key generation unit when the AV stream is not being played, and outputs the stop signal to the content interpretation unit when the AV stream is being played; a key generation unit generating a decryption key for decrypting the content in response to a signal corresponding to one of the second mode and the third mode, the generation of the decryption key being stopped in response to the stop signal; a content interpretation unit for decrypting the content using the decryption key, outputting the content in response to a signal corresponding to the fourth mode, and stopping the decryption of the content in response to the stop signal.

When the first copy control information and the second copy control information are different, the decryption unit stops processing the AV content.

When the first copy control information and the second copy control information are different, the decryption unit processes the AV stream using the copy control information with enhanced copy protection in both the first copy control information and the second copy control information.

To achieve the above and/or other aspects of the present invention, there is provided an audio/video (AV) stream processing system including: means for receiving an AV stream, the AV stream including a content information field and a content field; means for processing the AV stream; means for determining whether the copy control information of the content information field has been modified.

The processing means stops processing the AV stream when the copy control information has been modified. When the copy control information of the content information field has been modified, the processing means processes the AV stream using the copy control information having a higher priority out of both the copy control information of the content information field and the copy control information of the content field.

In order to achieve the above and/or other aspects of the present invention, there is provided another audio/video (AV) stream processing system, comprising: means for receiving an AV stream, the AV stream including a content information field and a content field, wherein the content information field includes first copy control information, and the content field includes second copy control information; means for processing the AV stream; means for determining whether the first copy control information and the second copy control information are different.

In order to achieve the above and/or other aspects of the present invention, there is provided another audio/video (AV) stream processing system, comprising: a reception unit that receives an AV stream, the AV stream including a content information field and a content field, wherein: the content information field includes first copy control information, and the content field includes second copy control information; a determination unit that compares the first copy control information and the second copy control information; and a decryption unit stopping processing the AV stream or processing the AV stream using copy control information having a higher priority of both the first copy control information and the second copy control information when the first copy control information and the second copy control information are different.

In order to achieve the above and/or other aspects of the present invention, there is provided another audio/video (AV) stream processing system, comprising: a reception unit that receives an AV stream, the AV stream including a content information field and a content field, wherein: the content information field includes first copy control information, and the content field includes second copy control information; a determination unit that determines whether the first copy control information has been modified when compared with the second copy control information. And a decryption unit processing the AV stream.

In order to achieve the above and/or other aspects of the present invention, there is provided an apparatus for copy control in an audio/video (AV) stream processing system that processes an AV stream including a content information field and a content field, the apparatus comprising: an extracting section that extracts copy control information of the content information field and copy control information of the content field from the AV stream; and a determination section that determines whether or not the copy control information of the content information field and the copy control information of the content field are different.

The determination means may determine whether the copy control mode information of the first copy control information and the second copy control information corresponding to the AV stream content is different in order to prevent unauthorized processing of the AV stream.

In order to achieve the above and/or other aspects of the present invention, there is provided another apparatus for copy control in an audio/video (AV) stream processing system that processes an AV stream, the apparatus comprising: an extracting section that extracts copy control information from a content information field of the AV stream; a determination section that determines whether the copy control information has been modified.

The determination means may determine whether the copy control information of the content information field has been modified when compared with the copy control information of the content field of the AV stream in order to prevent unauthorized processing of the AV stream.

In order to achieve the above and/or other aspects of the present invention, there is provided another apparatus for copy control in an audio/video (AV) stream processing system that processes an AV stream including a content information field and a content field, the apparatus comprising: an extracting section that extracts copy control information of the content information field and copy control information of the content field from the AV stream; and a comparison unit for comparing the copy control information of the content information field with the copy control information of the content field and determining whether the copy control information of the content information field and the copy control information of the content field are different.

In order to achieve the above and/or other aspects of the present invention, there is provided another apparatus for copy control in an audio/video (AV) stream processing system that processes an AV stream including a content information field and a content field, the apparatus comprising: an extracting section that extracts copy control information of the content information field and copy control information of the content field from the AV stream; a determination section that establishes a priority between the copy control information of the content information field and the copy control information of the content field when the copy control information of the content information field and the copy control information of the content field are different.

When the copy control information of the content information field and the copy control information of the content field are different, the determination means may make one of the copy control information of the content information field and the copy control information of the content field, which provides enhanced copy protection, as information for processing the AV stream. When the copy control information of the content information field and the copy control information of the content field are different, the determination means may make the copy control information of the content information field as information for processing the AV stream. When the copy control information of the content information field and the copy control information of the content field are different, the determination means may make the copy control information of the content field as information for processing the AV stream.

In order to achieve the above and/or other aspects of the present invention, there is provided an AV stream processing method including: receiving an AV stream including a content information field and a content field, wherein the content information field includes first copy control information and the content field includes second copy control information; determining whether the first copy control information and the second copy control information are different; the AV stream is processed based on the determination result.

The determining whether the first copy control information and the second copy control information are different may include determining whether copy control mode information of the first copy control information and the second copy control information is different. The processing of the AV stream may include processing the AV stream according to the copy control mode information when the first copy control information and the second copy control information are the same.

The processing of the AV stream may include stopping decrypting the content of the AV stream when the first copy control information and the second copy control information are different.

The processing of the AV stream may include stopping generation of a decryption key for decrypting the content of the AV stream when the first copy control information and the second copy control information are different.

The processing of the AV stream may include processing the content of the AV stream using copy control information with enhanced copy protection in both the first copy control information and the second copy control information when the first copy control information and the second copy control information are different.

When the first copy control information and the second copy control information are different, the processing of the AV stream may include one of stopping processing the AV stream and processing the AV stream using the copy control information having a higher priority of both the first copy control information and the second copy control information. When the first copy control information and the second copy control information are different, the processing of the AV stream may include processing the content of the AV stream using the second copy control information. When the first copy control information and the second copy control information are different, the processing of the AV stream may include processing the content of the AV stream using the first copy control information.

When the first copy control information and the second copy control information are different, the processing of the AV stream may include stopping decryption of the content of the AV stream when the AV stream is being played, or stopping generation of a decryption key for decrypting the content of the AV stream when the AV stream is not being played.

The above method may further include displaying a message indicating that processing of the AV stream is prohibited. The method may further include, when the first copy control information and the second copy control information are different, causing the second copy control information to have a higher priority than the first copy control information, wherein the processing of the AV stream includes processing the content of the AV stream using the second copy control information. The method may further include, when the first copy control information and the second copy control information are different, causing the first copy control information to have a higher priority than the second copy control information, wherein the processing of the AV stream includes processing the content of the AV stream using the first copy control information.

In order to achieve the above and/or other aspects of the present invention, there is provided another AV stream processing method including: receiving an AV stream including a content information field and a content field; determining whether copy control information of the content information field has been modified; the AV stream is processed based on the determination result.

The processing of the AV stream may include stopping processing of the AV stream when the copy control information has been modified.

The processing of the AV stream may include processing the AV stream using copy control information having a higher priority of both the copy control information of the content information field and the copy control information of the content field when the copy control information of the content information field has been modified.

In order to achieve the above and/or other aspects of the present invention, there is provided another AV stream processing method including: receiving an AV stream including a content information field including first copy control information and a content field including second copy control information, determining whether the first copy control information and the second copy control information are different in order to prevent unauthorized access of the AV stream, and processing the AV stream based on a result of the determination.

In order to achieve the above and/or other aspects of the present invention, there is provided another AV stream processing method including: receiving an AV stream including a content information field and a content field, wherein the content information field includes first copy control information and the content field includes second copy control information; comparing the first copy control information and the second copy control information, when the first copy control information and the second copy control information are different, performing one of two processes of stopping processing the AV stream and processing the AV stream using the copy control information having a higher priority of both the first copy control information and the second copy control information.

In order to achieve the above and/or other aspects of the present invention, there is provided another AV stream processing method including: receiving an AV stream including a content information field and a content field, wherein the content information field includes first copy control information and the content field includes second copy control information; it is determined whether the first copy control information has been modified, as compared with the second copy control information, and the AV stream is processed based on the determination result.

In order to achieve the above and/or other aspects of the present invention, there is provided a method for copy control in processing an audio/video (AV) stream including a content information field and a content field, the method including: extracting copy control information of the content information field and copy control information of the content field from the AV stream; it is determined whether the copy control information of the content information field and the copy control information of the content field are different.

The determining step may include determining whether copy control mode information of the first copy control information and the second copy control information corresponding to the AV stream contents are different in order to prevent unauthorized processing of the AV stream.

In order to achieve the above and/or other aspects of the present invention, there is provided another method for copy control in processing an audio/video (AV) stream, the method comprising: extracting copy control information from a content information field of the AV stream; it is determined whether the copy control information has been modified.

The determining step may include determining whether copy control information of the content information field has been modified compared with copy control information of the content field of the AV stream in order to prevent unauthorized processing of the AV stream.

In order to achieve the above and/or other aspects of the present invention, there is provided another method for copy control in processing an audio/video (AV) stream including a content information field and a content field, the method comprising: extracting copy control information of the content information field and copy control information of the content field from the AV stream; the copy control information of the content information field and the copy control information of the content field are compared to determine whether the copy control information of the content information field and the copy control information of the content field are different.

In order to achieve the above and/or other aspects of the present invention, there is provided another method for copy control in processing an audio/video (AV) stream including a content information field and a content field, the method comprising: comparing the copy control information of the content information field with the copy control information of the content field; when the copy control information of the content information field and the copy control information of the content field are different, priority is established between the copy control information of the content information field and the copy control information of the content field.

The step of establishing the priority includes making one of the copy control information of the content information field and the copy control information of the content field have enhanced copy protection than the other as information for processing the AV stream when the copy control information of the content information field and the copy control information of the content field are different. The establishing step may include making the copy control information of the content information field as information for processing the AV stream when the copy control information of the content information field and the copy control information of the content field are different. The establishing step may include making the copy control information of the content information field as information for processing the AV stream when the copy control information of the content information field and the copy control information of the content field are different.

Drawings

These and/or other aspects and advantages of the present invention will become more apparent and more readily appreciated from the following description of the various aspects of the invention, taken in conjunction with the accompanying drawings of which:

fig. 1 is a schematic diagram describing the structure of an AV stream.

Fig. 2 is a block diagram illustrating the structure of a conventional AV stream processing system.

Fig. 3 is a block diagram illustrating an AV stream processing system for data copy protection according to an embodiment of the present invention.

Fig. 4 is a block diagram illustrating an AV stream processing system for data copy protection according to another embodiment of the present invention.

Fig. 5 is a block diagram illustrating an AV stream processing system for data copy protection according to another embodiment of the present invention.

Fig. 6 is a flowchart describing a processing method for a copy-protected AV stream according to an embodiment of the present invention.

Fig. 7 and 8 are flowcharts describing an AV stream data copy control method when the first copy control information and the second copy control information are not identical according to another embodiment of the present invention.

Detailed Description

Reference will now be made in detail to the embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like elements throughout. The embodiments are described below in order to explain the present invention by referring to the figures. For convenience of description, an embodiment of the present invention will hereinafter be described with reference to a 2-bit copy control information code having four copy control information states in table 1 and corresponding to the respective copy control information states, it being understood that the present invention is not limited thereto. The copy control information state according to an exemplary embodiment of the present invention may include a part of the four states or more than the four states. The copy control information code is also not limited to 2-bit information and may be represented in any form capable of representing the state of the copy control information. In addition, the second copy control information may be the copy control information 130 contained in each sub-unit of the content field shown in fig. 1, or copy control information indicating each sub-unit.

Fig. 3 depicts an AV stream processing system for data copy protection according to one embodiment of the present invention. The AV stream processing system 300 includes an AV stream receiving unit 310, a modification determining unit 320, and a decrypting unit 330. The AV stream receiving unit 310 receives an AV stream and transfers the received AV stream to the modification determining unit 320. Referring to fig. 1 and 3, the modification determination unit 320 compares the first copy control information and the second copy control information in the AV stream. When it is determined that the value of the first copy control information is different from the value of the second copy control information, the AV stream processing system 300 determines whether to decrypt the AV stream according to a predetermined criterion.

When it is determined that the value of the first copy control information is the same as the value of the second copy control information, the decryption unit 330 performs a decryption operation corresponding to the value of the copy control information. At this time, when the value of the copy control information corresponds to "copy free", the AV stream does not need to be decrypted, and thus the decryption unit 330 transfers the AV stream (received by the AV stream receiving unit 310) to, for example, the AV stream output apparatus 340. When the value of the copy control information corresponds to "no more copy or never copy", "copy free but encrypted", or "copy once", the decryption unit 330 generates a decryption key using the second copy control information and other information from the modification determination unit 320, decrypts the AV content of the AV stream with the decryption key, and transmits the decrypted AV content to, for example, the AV stream output apparatus 340. The other information for generating the decryption key may include at least one of a seed value randomly generated for generating the decryption key, a public key value or a secret key value inherent to the AV device, and a public key value or a secret key value corresponding to a storage medium of the AV content. According to various aspects, the AV stream output apparatus 340 may include an electric or optical recording medium, a storage medium, on which the read AV stream can be recorded, or a display device, on which the read AV stream can be displayed. According to other aspects, the decryption unit 330 may transmit the decrypted AV contents using a wired or wireless transmission medium instead of the output device 340 described above.

Fig. 4 depicts an AV stream processing system for data copy protection according to another embodiment of the present invention. The AV stream processing system 400 includes an AV stream receiving unit 410 that receives an AV stream, a modification determining unit 420 that determines whether copy control information in the AV stream has been modified, and a control unit 430, and the control unit 430 determines whether to decrypt the AV stream according to the determination result of the modification determining unit 420 and transmits a command signal for decryption corresponding to a value of the copy control information to a decryption key generating unit 440. The AV stream processing system 400 further includes: a decryption key generation unit 440 receiving the decryption command from the control unit 430, generating a decryption key using the second copy control information from the modification determination unit 420 and other information for generating the decryption key; the content interpretation unit 450 decrypts the AV content of the AV stream using the decryption key transmitted from the decryption key generation unit 440, and transfers the decrypted AV content to one output device 460 among the above-described output devices known in the art.

The operation of the AV stream processing system 400 is described below by way of example. The AV stream receiving unit 410 receives the AV stream, transfers the AV stream to the modification determining unit 420, and simultaneously transfers the content of the AV stream to the content interpreting unit 450. At this time, the control unit 430 receives a control signal from the outside to control the operation of the AV device. For example, the control signal may be a signal that allows the AV device to play the contents of the AV stream or a signal that allows the AV device to copy the contents to a predetermined storage space.

The modification determining unit 420 extracts the first copy control information and the second copy control information of the AV stream to determine whether they have the same value. When the first copy control information and the second copy control information are different, the modification determining unit 420 determines that the first copy control information has been modified, and transmits a signal indicating that the copy control information has been modified to the control unit 430. In response, the control unit 430 transmits a command signal to the content interpretation unit 450 to stop decrypting the content, thereby preventing illegal copying of the content. At this time, the control unit 430 transmits a command signal to the decryption key generation unit 440 to stop the generation of the decryption key, thereby preventing the generation of the decryption key itself.

According to other aspects, the modification determining unit 420 may establish a priority between the first copy control information and the second copy control information when the first copy control information and the second copy control information are different or when it is determined that one of the first copy control information and the second copy control information has been modified. In this case, the control unit 430 determines whether to decrypt the AV stream according to a copy control information value having a higher priority than another copy control information. For example, when the first copy control information and the second copy control information are different, for example, having values "10" and "11", respectively (see table 1 above), copy control information having a larger copy protection value may be used, that is, when the priority established by the modification determination unit 420 is that the second copy control information takes precedence over the first copy control information, copy control information having a larger copy protection value "11" may be used rather than copy control information having a smaller copy protection value "10". Table 1 shows an example of the priority of the copy protection value, from "00" with the minimum copy protection value to "11" with the maximum copy protection value. A larger copy protection value provides enhanced copy protection than a smaller copy protection value.

When the modification determination unit 420 determines that the first copy control information and the second copy control information have the same value, or determines that, for example, the first copy control information is not modified, the modification determination unit 420 transfers the value of the first copy control information to the control unit 430, while transferring other information for generating a decryption key and the second copy control information to the decryption key generation unit 440. The other information may include at least one of a seed value randomly generated for generating a decryption key, a public key value or a secret key value inherent to the AV device, and a public key value or a secret key value corresponding to a storage medium of the AV content. The control unit 430 checks the value of the received first copy control information. When the value of the first copy control information corresponds to "copy free", the AV contents of the AV stream do not need to be decrypted, and thus the control unit 430 sends a command to the content interpretation unit 450 to transfer the received AV contents to the output device 460. When the value of the first copy control information corresponds to "no more copy or never copy", "copy free but encrypted", or "copy once", the control unit 430 transmits the first copy control information to the decryption key generation unit 440, thereby authorizing the decryption key generation unit 440 to generate a decryption key. At this time, the decryption key generation unit 440 generates a decryption key using the second copy control information and other information from the modification determination unit 420, and transmits it to the content interpretation unit 450.

The content interpretation unit 450 receives a command from the control unit 430, performs decryption on the AV content received from the AV stream reception unit 410, and decrypts the received AV content using the decryption key from the decryption key generation unit 440. The content interpretation unit 450 outputs the decrypted AV content to the output device 460. For example, the output device 460 may include an electric or optical recording medium, a storage medium, on which the read AV stream can be recorded, or a display apparatus which can display the read AV stream. According to other aspects, the content interpretation unit 450 may transmit the decrypted AV content using a wired or wireless transmission medium instead of the output device 460 as described above.

Fig. 5 depicts an AV stream processing system for data copy protection according to another embodiment of the present invention. The AV stream processing system 500 includes an AV stream receiving unit 510, a control unit 520, a decryption key generating unit 530, a modification determining unit 550, and a content interpreting unit 540. The modification determination unit 550 includes a Copy Control Information (CCI) storage unit 552 and a CCI comparison unit 554.

The AV stream receiving unit 510 receives an AV stream and transfers AV contents in the AV stream to the content interpreting unit 540. The control unit 520 receives first copy control information contained in the AV stream transmitted from the AV stream receiving unit 510, transmits a command signal corresponding to the first copy control information to the decryption key generating unit 530 and the content interpreting unit 540, and transmits the first copy control information received from the AV stream receiving unit 510 to the CCI storage unit 552. The decryption key generation unit 530 receives the second copy control information and other information for generating a decryption key contained in the AV stream from the AV stream reception unit 510, generates the decryption key when the control unit 520 authorizes the generation of the decryption key, and transmits the generated decryption key to the content interpretation unit 540. The modification determination unit 550 determines whether the copy control information has been modified. The CCI storage unit 552 receives and stores the first copy control information from the control unit 520. The CCI comparison unit 554 receives the second copy control information transmitted from the decryption key generation unit 530 and compares with the value of the first copy control information in the CCI storage unit 552 to determine whether the first copy control information has been modified. The content interpreting unit 540 receives the command to decrypt the AV content of the AV stream from the control unit 520 and the decryption key from the decryption key generating unit 530, and decrypts the AV content received from the AV stream receiving unit 510. The content interpreting unit 540 transfers the decrypted AV content to the output device 560.

The operation of the AV stream processing system 500 is described in detail below. The AV stream receiving unit 510 receives an AV stream and transfers first copy control information contained in the AV stream to the control unit 520. The AV stream receiving unit 510 simultaneously transmits the second copy control information contained in the AV stream to the decryption key generating unit 530 and transmits the AV contents of the AV stream to the content interpreting unit 540. The control unit 520 receives an externally input control signal to control the operation of the AV device. For example, the control signal may be a signal that allows an AV device to play AV content of an AV stream or a signal that copies the AV content to a predetermined storage space.

When the value of the first copy control information corresponds to "copy free", the AV content does not need to be decrypted, and thus the control unit 520 sends a command to the content interpretation unit 540 to transfer the received AV content to the output device 560. When the value of the first copy control information corresponds to "no more copy or never copy", "copy free but encrypted", or "copy once", the control unit 520 transmits the first copy control information to the decryption key generation unit 530, so that the authorization unit 530 generates a decryption key. At this time, the decryption key generation unit 530 generates a decryption key using the second copy control information previously received from the AV stream reception unit 510 and other information for generating the decryption key. The decryption key generation unit 530 transmits the generated decryption key to the content interpretation unit 540. The other information may include at least one of a seed value randomly generated for generating a decryption key, a public key value or a secret key value inherent to the AV device, a public key value or a secret key value of a storage medium corresponding to the AV content, and the like.

The CCI comparison unit 554 receives the second copy control information transmitted from the decryption key generation unit 530 and compares it with the value of the first copy control information stored in the CCI storage unit 552, determines whether the first copy control information has been modified, and transmits the determination result to the control unit 520. When the value of the first copy control information is different from the value of the second copy control information, it is determined that the first copy control information has been modified. In this case, the control unit 520 transmits a command to pause the decryption of the AV content to the content interpretation unit 540, and thus the content interpretation unit 540 does not decrypt the received AV content, e.g., the AV stream processing system 500 pauses the playback of the AV content. According to other aspects, the control unit 520 may transmit a command signal to suspend the generation of the decryption key to the decryption key generation unit 530, thereby stopping the generation of the decryption key itself.

According to other aspects, the modification determining unit 550 may establish a priority between the first copy control information and the second copy control information when the first copy control information and the second copy control information are different. In this case, the control unit 520 determines whether to decrypt the AV stream according to the value of the copy control information having a higher priority than another copy control information.

When it is determined that the first copy control information and the second copy control information have the same value, the determination result is transmitted to the control unit 520. The control unit 520 sends a command to the content interpreting unit 540 to decrypt the AV content of the AV stream that has been received from the AV stream receiving unit 510. The content interpretation unit 540 receives a command from the control unit 520 to perform decryption on the AV content that has been received from the AV stream reception unit 510, and decrypts the received AV content using the decryption key transmitted from the decryption key generation unit 530. The content interpretation unit 540 outputs the decrypted AV content to the output device 560. For example, the output device 560 may include an electric or optical recording medium, a storage medium, on which the read AV stream can be recorded, or a display apparatus, on which the read AV stream can be displayed. According to other aspects, the content interpretation unit 540 may transmit the decrypted AV content using a wired or wireless transmission medium instead of the output device 560 described above.

As described above, according to an aspect of the present invention, the CCI comparison unit 554 of the modification determination unit 550 compares the first copy control information and the second copy control information, and transmits the comparison result to the control unit 520, and transmits a command signal corresponding to the comparison result to the content interpretation unit 540. According to another aspect, the CCI comparison unit 554 may directly transmit the command to the content interpretation unit 540.

Fig. 6 depicts a flowchart of an AV stream processing method for copy protection according to an embodiment of the present invention. As shown in fig. 6, at steps 605 and 610, an AV stream is input and the input AV stream is temporarily stored in a temporary storage space, respectively. In step 615, the first copy control information and the second copy control information included in the AV stream are extracted and compared with each other. When the values of the first copy control information and the second copy control information are different, the method proceeds to step 670, which will be described in detail with reference to fig. 7 and 8.

When the values of the first copy control information and the second copy control information are the same, the corresponding process in step 625 is performed. For example, when the values of the first copy control information and the second copy control information are "copy free", that is, "00", it is not necessary to decrypt the AV contents of the AV stream. The AV stream is directly copied in step 630. When the values of the first copy control information and the second copy control information are "copy-free but encrypted" or "copy-once", that is, "01" or "10", a decryption key is generated in step 635 in order to decrypt the AV stream. When the values of the first copy control information and the second copy control information are "no more copy or never copy", that is, "11", it is checked whether the AV stream is being played in step 640. When the AV stream is being played, decryption of the AV stream for copying the AV contents is not performed in step 645. When the AV stream is not being played, a decryption key for decrypting the content is not generated in step 650. In step 655, a message is provided by a prior art existing display device (not shown) indicating that the AV stream cannot be decrypted due to copy inhibition.

Fig. 7 and 8 are flowcharts describing an AV stream data copy control method when the first copy control information and the second copy control information are different according to another embodiment of the present invention. Fig. 7 depicts that unconditional decryption of AV contents is not performed, and fig. 8 depicts that decryption of AV streams is determined based on copy control information values having higher priorities by establishing priorities between the first copy control information and the second copy control information.

Referring to fig. 7, when the values of the first copy control information and the second copy control information are different, it is checked whether an AV stream to be copied is being played in step 705. When the AV stream is being played, it means that the decryption key has been generated, so the decryption process using the decryption key is not performed in step 710. When the AV stream is not being played, a decryption key is not generated in step 715. In step 720, a message indicating that the AV stream cannot be decrypted due to copy inhibition is provided through a display device (not shown) existing in the related art.

Referring to fig. 8, when the values of the first copy control information and the second copy control information are different, it is checked which copy control information has a higher Priority, and the copy control information having the higher Priority is set to "Priority _ CCI _ information" ("Priority _ CCI _ info"). According to an aspect of the present invention, it is checked whether the first copy control information has priority in step 750, and if the first copy control information has priority, the first copy control information is set to 'priority _ CCI _ info' in step 754, and if the first copy control information does not have priority, the second copy control information is set to 'priority _ CCI _ info' in step 754.

When the value of "priority _ CCI _ info" is "00", that is, "copy free", the AV stream is not encrypted, allowing copy free. In this case, since there is no need to decrypt the AV contents of the AV stream, the AV stream is directly copied in step 758. When the value of the "priority _ CCI _ info" is "01" or "10", that is, "copy free but encrypted" or "copy once", a decryption key is generated in step 760 in order to decrypt the AV stream. At this time, the value of "10" means that only one copy is permitted and the copy of the content is prohibited thereafter, so that the value of the copy control information after the copy becomes "11". When the value of "priority _ CCI _ info" is "11", that is, "no more copies or never copies", decryption of AV content is absolutely prohibited. In this case, it is checked in step 762 whether the AV stream is being played. When the AV stream is being played, it means that the decryption key has been generated, and therefore, the decryption process using the decryption key is not performed in step 764. When the AV stream is not being played, no decryption key is generated in step 766. In step 768, a message indicating that the AV stream cannot be decrypted due to copy inhibition is provided by a display device (not shown) already known in the art.

As described above and apparent from the above description, the apparatus and method for unauthorized copy protection of contents according to the present invention can be applied to various systems and apparatuses that can be implemented by hardware and/or software, including digital home appliances and other appliances for storing and/or playing AV streams with or without copy control information. It is understood that the AV stream may be data for audio and/or video recording and the unauthorized process may be unauthorized access, display, copying or a combination thereof.

It will also be appreciated that systems employing the present invention also include permanent or removable memory such as magnetic or optical disks, RAM, ROM, carrier wave media, etc., on which processes and data structures of the present invention may be stored and used for distribution. The operation process may also be distributed by downloading over a network such as the internet.

It should be further understood that while the illustrative, non-limiting embodiments of the present invention overcome the above-described disadvantages and other disadvantages not described herein, the present invention is not required to overcome the above-described disadvantages and that the illustrative, non-limiting embodiments of the present invention may not overcome any of the problems described above.

Although a few embodiments of the present invention have been shown and described, it would be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the claims and their equivalents.

Claims (35)

1. An audio/video (AV) stream processing system comprising:

means for receiving an AV stream, the AV stream including a content information field and a content field, wherein the content information field includes first copy control information, and the content field includes second copy control information;

means for processing the AV stream; and

means for determining whether the first copy control information and the second copy control information are different;

wherein, when the first copy control information and the second copy control information are different, the processing of the AV stream includes one of stopping the processing of the AV stream and processing the AV stream using one of the first copy control information and the second copy control information having a higher priority.

2. The system of claim 1, wherein:

the means for receiving an AV stream is a receiving unit that receives an AV stream;

the means for determining whether the first copy control information and the second copy control information are different is a determination unit; and

the means for processing the AV stream is a decryption unit that processes the AV stream.

3. The system of claim 2, wherein the determination unit determines whether the copy control mode information of the first copy control information and the second copy control information is different.

4. The system according to claim 2, wherein the decryption unit stops generating a decryption key for decrypting the content of the AV stream when the first copy control information and the second copy control information are different.

5. The system according to claim 2, wherein when the first copy control information and the second copy control information are different, the decryption unit processes the content of the AV stream according to the copy control information having a higher priority in both the first copy control information and the second copy control information.

6. The system of claim 5, wherein when the first copy control information and the second copy control information are different, the second copy control information has priority over the first copy control information.

7. The system of claim 5, wherein when the first copy control information and the second copy control information are different, the first copy control information has priority over the second copy control information.

8. The system according to claim 5, wherein the determination unit establishes priority between the first copy control information and the second copy control information when the first copy control information and the second copy control information are different.

9. The system of claim 2, wherein

Each of the first copy control information and the second copy control information includes a copy control mode of the AV stream content, an

The copy control mode includes: a first mode, content encryption and absolute copy inhibition; a second mode in which the contents are encrypted and one-time copy is permitted, wherein the second mode is changed to the first mode after one-time copy; a third mode, content encryption and allowing unlimited copying; and a fourth mode in which the content is not encrypted and unlimited copying is allowed.

10. The system of claim 9, wherein the decryption unit comprises:

a key generation unit that generates a decryption key for decrypting the content;

a content interpretation unit decrypting the content using the decryption key; and

and a control unit which controls the key generation unit and the content interpretation unit to stop generating the decryption key or to stop decrypting the content when the first copy control information and the second copy control information are different, and controls the key generation unit and the content interpretation unit according to the copy control mode when the first copy control information and the second copy control information are the same.

11. The system of claim 10, wherein the key generation unit generates the decryption key using information including the second copy control information.

12. The system of claim 10, wherein the control unit controls the key generation unit to generate the decryption key for decrypting the content in response to one of a first mode, a second mode, and a third mode of the copy control mode, and controls the content interpretation unit to output the content in response to a fourth mode of the copy control mode.

13. The system of claim 12, further comprising a storage unit that stores the decrypted content or the undecrypted content.

14. The system of claim 12, further comprising a display unit that displays the decrypted content or the undecrypted content.

15. The system of claim 9, wherein the determining unit comprises:

a storage unit that stores first copy control information; and

and a comparing unit comparing the copy control pattern of the first copy control information with the copy control pattern of the second copy control information.

16. The system of claim 9, wherein the decryption unit comprises:

a control unit outputting a signal corresponding to a copy control mode when the first copy control information and the second copy control information are the same; generating a stop signal when the first copy control information and the second copy control information are different, wherein the control unit outputs the stop signal to the key generation unit when the AV stream is not being played, and outputs the stop signal to the content interpretation unit when the AV stream is being played;

a key generation unit generating a decryption key for decrypting the content in response to a signal corresponding to one of the first mode, the second mode, and the third mode, and stopping generation of the decryption key in response to the stop signal; and

a content interpretation unit for decrypting the content using the decryption key, outputting the content in response to a signal corresponding to the fourth mode, and stopping the decryption of the content in response to the stop signal.

17. The system according to claim 2, wherein the decryption unit processes the AV stream using the copy control information with enhanced copy protection in both the first copy control information and the second copy control information when the first copy control information and the second copy control information are different.

18. The system of claim 2, wherein

The determination unit compares the first copy control information and the second copy control information to perform the determination; and

when the first copy control information and the second copy control information are different, the decryption unit stops processing the AV stream or processes the AV stream using the copy control information having a higher priority of both the first copy control information and the second copy control information.

19. An apparatus for copy control in an audio/video (AV) stream processing system that processes an AV stream including a content information field and a content field, the apparatus comprising:

an extracting section that extracts first copy control information of the content information field and second copy control information of the content field from the AV stream; and

a determination section that determines whether or not the first copy control information of the content information field and the second copy control information of the content field are different;

wherein the determination means determines whether or not the copy control mode information corresponding to the first copy control information and the second copy control information of the content of the AV stream is different, and establishes a priority between the first copy control information of the content information field and the second copy control information of the content field when the first copy control information of the content information field and the second copy control information of the content field are different, so as to prevent unauthorized processing of the AV stream;

wherein the determination means makes one of the first copy control information of the content information field and the second copy control information of the content field, which provides enhanced copy protection, as information for processing the AV stream when the first copy control information of the content information field and the second copy control information of the content field are different.

20. The apparatus according to claim 19, wherein when the first copy control information of the content information field and the second copy control information of the content field are different, if the first copy control information of the content information field provides enhanced copy protection, the determining means makes the first copy control information of the content information field as information for processing the AV stream.

21. The apparatus according to claim 19, wherein when the first copy control information of the content information field and the second copy control information of the content field are different, if the second copy control information of the content field provides enhanced copy protection, the determining means makes the second copy control information of the content field as information for processing the AV stream.

22. An AV stream processing method, comprising:

receiving an AV stream including a content information field and a content field, wherein the content information field includes first copy control information and the content field includes second copy control information;

determining whether the first copy control information and the second copy control information are different; and

processing the AV stream based on the determination result;

wherein the processing of the AV stream includes one of two processes of stopping processing of the AV stream and processing the AV stream using the copy control information having a higher priority of both the first copy control information and the second copy control information when the first copy control information and the second copy control information are different.

23. The method of claim 22, wherein the step of determining whether the first copy control information and the second copy control information are different comprises determining whether copy control mode information of the first copy control information and the second copy control information are different.

24. The method of claim 23, wherein the processing of the AV stream comprises processing the AV stream according to the copy control mode information when the first copy control information and the second copy control information are identical.

25. The method of claim 22, wherein the processing of the AV stream comprises stopping generation of a decryption key for decrypting the content of the AV stream when the first copy control information and the second copy control information are different.

26. The method of claim 22, wherein the processing of the AV stream comprises processing the content of the AV stream using copy control information with enhanced copy protection in both the first copy control information and the second copy control information when the first copy control information and the second copy control information are different.

27. The method of claim 22, wherein when the first copy control information and the second copy control information are different, the processing of the AV stream includes stopping decryption of content of the AV stream when the AV stream is being played, or stopping generation of a decryption key for decrypting the content of the AV stream when the AV stream is not being played.

28. The method of claim 22, further comprising displaying a message indicating that processing of the AV stream is prohibited.

29. The method of claim 22, wherein the processing of the AV stream comprises processing the content of the AV stream using the second copy control information when the first copy control information and the second copy control information are different and the second copy control information has a higher priority.

30. The method of claim 22, wherein the processing of the AV stream comprises processing the content of the AV stream using the first copy control information when the first copy control information and the second copy control information are different and the first copy control information has a higher priority.

31. The method of claim 22, further comprising causing the second copy control information to have a higher priority than the first copy control information when the first copy control information and the second copy control information are different, wherein the processing of the AV stream includes processing the content of the AV stream using the second copy control information.

32. The method of claim 22, further comprising causing the first copy control information to have a higher priority than the second copy control information when the first copy control information and the second copy control information are different, wherein the processing of the AV stream includes processing content of the AV stream using the first copy control information.

33. A method for copy control in processing an audio/video AV stream including a content information field and a content field, the method comprising:

extracting first copy control information of a content information field and second copy control information of the content field from the AV stream;

comparing the copy control information of the content information field with the copy control information of the content field; and

determining whether first copy control information of the content information field and second copy control information of the content field are different;

wherein the determining step includes determining whether copy control mode information corresponding to first copy control information and second copy control information of the content of the AV stream is different, and establishing a priority between the first copy control information of the content information field and the second copy control information of the content field when the first copy control information of the content information field and the second copy control information of the content field are different, so as to prevent unauthorized processing of the AV stream;

wherein the step of establishing the priority includes causing one of the first copy control information of the content information field and the second copy control information of the content field to have enhanced copy protection than the other as information for processing the AV stream when the first copy control information of the content information field and the second copy control information of the content field are different.

34. The method of claim 33, wherein the step of establishing the priority includes causing the first copy control information of the contents information field to be information for processing the AV stream if the first copy control information of the contents information field provides enhanced copy protection when the first copy control information of the contents information field and the second copy control information of the contents field are different.

35. The method of claim 33, wherein the step of establishing the priority includes causing the second copy control information of the content field to be information for processing the AV stream if the second copy control information of the content field provides enhanced copy protection when the first copy control information of the content information field and the second copy control information of the content field are different.