KR100677000B1 - An apparatus and method for transmitting additional information on copy protection - Google Patents

Abstract

The present invention relates to an apparatus and a method for transmitting additional information for copy protection during transmission between devices in an RF band of a video signal according to the digital TV standard broadcasting standard, and an additional method for copy protection of a video signal according to the present invention. The information transmission method includes a first step of dividing a band overlapping with a video signal band of a digital broadcasting method into a transmission and reception band for exchanging additional data; A second step of transmitting a data frame of a digital broadcast format including copy protection information to a counterpart device; And a third step of transmitting and receiving additional data for generating a key necessary for mutual authentication between the two devices and generation of a key required for data encryption and decryption after transmission of the data frame by using the transmission and reception bands of the divided additional data. The transmission of the information related to the encryption and decryption of the video data and the copy protection information between the two devices is performed by appropriately dividing the frequency band according to the digital TV standard broadcasting standard or by using additional classification information. By doing so, it is a very useful invention that can prevent the illegal copying of video contents even when sending and receiving video signals in a digital TV broadcasting method.

VSB, BPSK, DVD Player, Digital TV, Copy Protection

Description

An apparatus and method for transmitting additional information for copy protection of an image signal             

1 is a diagram showing the overall configuration when a DVD player and a digital TV in which an additional information transmission apparatus for copying a video signal according to the present invention are implemented are connected and connected by a single cable.

2 is a flowchart illustrating a preferred embodiment of a method for transmitting additional information for copy protection of a video signal according to the present invention.

3 shows a frame in VSB format including copy protection information;

FIG. 4 is a diagram illustrating a transmission form of data and commands performed in the transmission device of FIG.

5 shows a frame in BPSK format,

6 shows a mapping form of an AKE command and a BPSK frame;

FIG. 7 is a diagram showing the overall configuration when a DVD player and a digital TV in which an additional information transmission apparatus for copying a video signal according to the present invention are implemented are connected by two cables.

8 shows another format of a VSB frame,

Fig. 9 shows a VSB format frame in which an AKE command is recorded in the data area.

FIG. 10 shows a form of data and command transmission in the transmission device of FIG.

FIG. 11 is a diagram showing the overall configuration when a DVD player and a digital TV in which an additional information transmission apparatus for copying a video signal according to the present invention are implemented are connected and connected by a single cable.

FIG. 12 shows a form of data and command transmission in the transmission device of FIG.

FIG. 13 shows the overall configuration when the DVD player and the digital TV in which the additional information transmission apparatus for preventing copying of video signals according to the present invention are implemented are connected and connected by a single cable.

FIG. 14 shows a transmission form of data and commands in the transmission device of FIG.

Figure 15 shows another format of a VSB frame.

※ Explanation of code for main part of drawing

100: DVD player 110, 210: VSB copy protection subsystem

120, 221: VSB modulator 121, 220: VSB demodulator

130, 240: BPSK demodulator 140, 230: BPSK modulator

200: digital television

The present invention relates to an apparatus and method for transmitting additional information for copy protection during inter-device transmission of a video signal in the RF band according to the digital TV standard broadcasting standard.

When a video signal is transmitted between a digital TV and an external device (for example, a digital VCR) connected through a digital interface such as IEEE 1394, the recording medium is copy-protected, i.e., playback video is recorded by another device. Send copy protection information to prevent Therefore, when the copy protection information is received together with the video signal, the other device does not perform playback or recording.

However, in the case of transmitting video signals between devices in the VSB format according to the digital TV broadcasting system, there is no standard for copy protection, so that the playback device provides the video signal as a VSB format RF signal to a TV or other recording device. When the video signal is decoded or output or recorded on the recording medium, there is a fear that the video contents of the recording medium to be copy-protected are copied to another recording medium.

Accordingly, the present invention has been made to solve the above problems, and provides an apparatus and method for transmitting additional information for copy protection when providing an image in a digital broadcast format to a counterpart device. It is.

In accordance with another aspect of the present invention, there is provided an apparatus for transmitting additional information for preventing video signal copying, including: modulating means for modulating video data into a digital broadcast format and transmitting the RF data in a designated band; Among the signals in the same band as the video data transmission / reception band, the signal of the band-divided reception band is demodulated by a signal system different from that of the digital broadcasting system, and the data to be transmitted is also modulated by the signal system to be different from the reception band. Additional data modulation and demodulation means for modulating a signal in a transmission / reception band of video data; And generating copy protection information of the image data and transmitting it through the modulating means, and receiving additional data necessary for encrypting or decrypting the image data through the additional data modulation / demodulation means, and then determining reproduction or transmission of the image data. It is characterized by being configured to include means,

Also, a method of transmitting additional information for preventing copying of a video signal according to the present invention includes: a first step of dividing a band overlapping with a video signal band of a digital broadcasting method into a transmission and reception band for exchanging additional data; A second step of transmitting a data frame of a digital broadcast format including copy protection information to a counterpart device; And a third step of transmitting and receiving additional data for generating a key necessary for mutual authentication between the two devices and generation of a key required for data encryption and decryption after transmission of the data frame by using the transmission and reception bands of the divided additional data. It is characterized by what is done, including.

Hereinafter, a preferred embodiment of an apparatus and a method for transmitting additional information for copy protection of a video signal according to the present invention will be described in detail with reference to the accompanying drawings.

1 is a diagram showing the overall configuration when a DVD player 100 and a digital TV 200 in which an additional information transmission apparatus for copying a video signal according to the present invention are implemented are connected and connected by a single cable. The DVD player 100 includes a VSB copy protection subsystem 110, a VSB (Vestigial Side Band) modulator 120 for modulating data according to a VSB scheme, which is a digital TV standard transmission standard, and a digital TV. And a BPSK demodulator (130) for demodulating received commands according to a BPSK (Binary PSK) scheme, and a BPSK modulator (140) for modulating transmission commands according to a BPSK scheme. The TV 200 includes a VSB copy protection subsystem 210, a VSB demodulator 220 that demodulates VSB format data transmitted from the DVD player 100, a BPSK demodulator 240, and a BPSK modulator 230. ) Is configured to include.

2 is a flowchart illustrating a preferred embodiment of a method for transmitting additional information for copying an image signal according to the present invention. Hereinafter, the method for transmitting additional information of FIG. 2 according to the present invention will be described with reference to the configuration of FIG. 1. It explains in detail.

First, copy control information (CCI) is recorded in the data area of the recording medium (DVD) inserted into the DVD player 100 together with the reproduction data (Content), so that the digital TV 200 can be recorded. When the playback request of the recording medium is input, the DVD player 100 generates encrypted protection indicator (EMI) information using the copy control information. The copy protection information is shown in FIG. Similarly, the size is 2 bits, and the contents are one of the following four types, for example.

1. No copy allowed, 2. One more copy allowed, 3. No more copies allowed, 4. Free copy allowed

When the EMI information is generated in this way, the VSB copy protection subsystem 110 in the DVD player 100 configures a data frame of the VSB format including the EMI information in the form shown in FIG. Null data is recorded, and the EMI information is inserted and recorded after field sync of the VSB format data frame as ECS (Encryption Control Segment) information along with other information (E / O, FEC). In the following, the data frame of the VSB format will be described in detail.
The VSB format data frame consists of two data fields, each data field comprising 313 data segments, the first data segment of each data field having its own data field sink, and each of the remaining 312 data segments A transport packet of 188 bytes and its associated forward error correction (FEC) overhead are transmitted.
On the other hand, each data segment constitutes 832 symbols, the first four symbols providing segment synchronization, the data segment synchronization signal also representing a sync byte of a 188 byte MPEG compatible transport packet, each data The remaining 828 symbols in the segment will carry the same data as the 187 bytes of the transport and its associated FEC overhead.

The VSB copy protection subsystem 110 transmits the VSB format data frame as shown in FIG. 3 to the VSB modulator 120. Accordingly, the VSB format data frame is modulated according to the VSB transmission format. The RF signal is provided to the digital TV 200 through a cable.

In this case, as the provided RF channel, channel 3 and channel 4 may be allocated as shown in FIG. 4, and in the case of video data (Contents), since the signal is unidirectional, there is no distinction between the transmission band and the reception band. All the frequency bands of RF 6MHz are used, and the additional data command is bidirectional. Therefore, the allocated 6MHz frequency band is divided into a transmission band 3MHz and a reception band 3MHz.

Accordingly, the VSB modulator 120 modulates the data frame of the VSB format into a signal of 6 MHz band and loads it on a carrier frequency of channel 3 or channel 4 to transmit it to the counterpart device, that is, the digital TV 200. (1 in Fig. 2).

Accordingly, the VSB demodulator 220 of the digital TV 200 receives a data frame by VSB demodulating the RF signal transmitted from the DVD player 100, and decodes it by extracting ECS information from the decoded data. This is provided to the VSB copy protection subsystem 210. Upon receipt of the ECS information of the VSB copy protection subsystem 110, the digital TV 200 requests authentication from the DVD player 100 (2 in FIG. 2), thereby allowing both devices to authenticate and authenticate each other. In order to exchange the key, each AKE (AKE: Authentication and Key Exchange) command is sent to the other device. In order to transmit the AKE command, each BPSK modulator 140 or 230 of each device modulates the AKE command provided from each VSB copy protection subsystem 110 or 210 according to the BPSK transmission format to convert the modulated AKE command. As shown in (2) of FIG. 4, the frequency band is divided into a transmission band (3 MHz) and a reception band (3 MHz), and the RF transmission band is transmitted to the counterpart device (3 in FIG. 2).

At this time, the transmitted AKE command is transmitted in the form of a BPSK frame format as shown in FIG. .
That is, the command expressed in the upper part of FIG. 6 is an AKE command defined by DTCP (Digital Transmission Content Protection). In the present invention, N AKE command fragments are generated by mapping the AKE commands by 32 bytes each. Two bytes of sync (SYNC) and four bytes of parity are added to configure the BPSK frame format by the BPSK modulator.

On the other hand, the transmission and reception of the divided command band is determined depending on whether or not the source of the video signal is provided. ② in FIG. 4 shows the viewpoint of the source of the video signal. For destination devices other than the original, the transmit and receive bands are switched. That is, in the digital TV 200 of FIG. 1, the command bands are set in the order of Rx and Tx, so that command transmission and reception with the DVD player 100 is performed.

In the VSB copy protection subsystems 110 and 210 of the device that receives the AKE command transmitted from the counterpart device, the partner device determines whether to authenticate the counterpart device using the AKE command demodulated by the BPSK demodulators 130 and 240. When the other side device is authenticated, a key to be used when encrypting or decrypting data is generated using the received AKE command and EMI information.

When the key is generated in this way, the VSB copy protection subsystem 110 of the DVD player 100 encrypts the data recorded on the recording medium using the generated key, and generates the encryption. The data frame of the VSB format as shown in FIG. 3 including the data and the EMI information is transmitted to the digital TV 200 as a VSB RF signal through the VSB modulator 120 (4 in FIG. 2). ), The encoded data is interleaved by the VSB specification at the time of transmission and transmitted.

The VSB demodulator 220 of the digital TV 200 receiving the VSB RF signal as described above tunes the RF signal to extract the signal as data, and the extracted data is transferred to the VSB copy protection subsystem 210. The transmitted data in the received frame is decrypted using a key previously generated from the AKE command and EMI information obtained by the above-described signal exchange, so that playback is performed.

Until now, the DVD player 100 and the digital TV 200 are connected via a single cable, and the communication between the DVD player 100 and the digital TV 200 differs depending on whether a data or command is applied. Unlike the embodiment of the present invention, an embodiment of exchanging data and commands in the same VSB format between the DVD player 100 and the digital TV 200 connected through two cables will be described.

7 illustrates another configuration of a DVD player and a digital TV in which an additional information transmission apparatus for copying a video signal according to the present invention is implemented.

First, the DVD player 100 and the digital TV 200 are connected and connected by two cables, and in order to transmit the AKE command in the VSB format, the VSB modulator 221 instead of the BPSK modulators 140 and 130 of FIG. 1 described above. ) And a demodulator 121 are included.

In the above configuration, since two RF bands are secured by using separate cables, bidirectional data transmission and reception between the DVD player 100 and the digital TV 200 may be performed without distinguishing between image data and commands. That is, since one cable is connected to the transmitting and receiving ends of both devices, the same RF band (channel 3 or channel 4) may be used for transmission and reception signals carried on each cable. At this time, the image data and the command are not distinguished by the band or the method, so a field for distinguishing the image data must be secured in the VSB format. This will be described in detail as follows.

When the VSB copy protection subsystem 110 or 210 sends data to the counterpart device, the VSB format data frame forms a VSB format data frame irrespective of an image or a command, and the data area of the VSB format frame is encoded as described above. By recording the selected data or the AKE command, and further recording the ECS information in the Field Sync area, further including type information indicating whether the current field is a command or encrypted data. In a device receiving a data frame in VSB format, it is possible to identify whether a field currently received is a command or encrypted image data.

That is, when encrypted image data is loaded in a VSB format data frame as shown in FIG. 8, a value of 0 is recorded in the C / D field, which is type information, and if an AKE command is transmitted to the counterpart device in the data field, As shown in FIG. 9, the device which receives the VSB format data frame by writing an AKE command and dummy random data in the data field of the VSB format frame and making the C / D field 1 is used. It is possible to correctly identify a field with a command instead of image data.

In case of transmitting data in VSB format as described above, since two cables having independent bands are connected between the transmitting and receiving terminals as shown in FIG. 10, the frequency band of the VSB signal is changed to channel 3 or channel 4. If both devices are set to match, video data or commands can be transmitted and received between the devices.

11 is the same as the configuration of FIG. 7, except that the DVD player 100 and the digital TV 200 are connected and connected via a single cable having a wide transmission bandwidth. In this case, as shown in FIG. Since the frequency bands for transmitting and receiving are not the same and are divided into a transmission band and a reception band, respectively, the filter band is changed according to transmission or reception to transmit and receive image data and commands. In this case, in order to match the transmission / reception bands between the two devices, the video signal source specifies channel 3 as the transmission band, and the side receiving the video signal designates channel 4 as the transmission band or as an external selection switch to the transmission band. Determine the channel to assign. For example, when the selection switch of the DVD player 100 is set to channel 3, the transmission band is designated as channel 3 and the reception band is designated as channel 4, so that the digital TV 200 sets the selection switch to channel 4. . Accordingly, in the digital TV 200, channel 4 is designated as a transmission band and channel 3 is a reception band so that transmission and reception bands are matched between the two devices.

FIG. 13 is the same as the configuration of FIG. 1, but in order to enable transmission and reception of video data in a VSB format in both directions, the DVD player 100 further includes a VSB demodulator 121 in the configuration of FIG. The digital TV 200 further includes a VSB modulator 221. In this case, a single cable connected between both devices has a wide transmission bandwidth.

Since the image data is bidirectional, the transmission / reception band of each device must also be determined in order to match the transmission and reception bands. The above-described determination method may be applied as it is.

In this case, since the frequency band is divided into data and command transmission bands as shown in Fig. 14, it is not necessary to secure and use the C / D field in the ECS information recorded in the field sync area in the frame of the VSB format. .

Unlike the above-described embodiment, the ECS information including the copy protection information may be recorded in the first segment of the VSB format data area instead of the field sink area as shown in FIG.

The additional information transmission apparatus and transmission method for preventing copying of video signals according to the present invention configured as described above may be performed by appropriately dividing a frequency band according to the digital TV standard broadcasting standard or by using additional classification information. By transmitting information related to encryption and decryption of video data and copy protection information in VSB format, it is very useful to prevent illegal copying of video contents even when sending and receiving video signals through digital TV broadcasting. It is an invention.

Claims (20)

delete In the video signal transmission and reception method, A first step of dividing a band overlapping with a video signal band of a digital broadcasting method into a transmission and reception band for exchanging additional data; A second step of transmitting a data frame of a digital broadcast format including copy protection information to a counterpart device; A third step of transmitting and receiving additional data for generation of a key required for mutual authentication between the two devices and generation of a key required for data encryption and decryption after transmission of the data frame by using the transmission and reception bands of the divided additional data; A fourth step of performing authentication and key generation of the counterpart device by using the additional information received by the third step; And And a fifth step of performing an encryption process of the image data to be transmitted by using the generated key when the counterpart device is authenticated. In the video signal transmission and reception method, A first step of dividing a band overlapping with a video signal band of a digital broadcasting method into a transmission and reception band for exchanging additional data; A second step of transmitting a data frame of a digital broadcast format including copy protection information to a counterpart device; And A third step of transmitting / receiving additional data for generating a key required for mutual authentication between the two devices and generation of a key required for data encryption and decryption after transmission of the data frame using the transmission and reception bands of the divided additional data; Including but not limited to And the copy protection information is recorded in a field sync area of a data frame of the digital broadcast format. delete In the video signal transmission and reception method, A first step of constructing a data frame of a digital broadcast format including copy protection information; A second step of generating information for distinguishing additional data from image data and inserting the information into the configured data frame; Transmitting a data frame including the division information as a signal of a designated band to a counterpart device; And And a fourth step of transmitting and receiving the additional data for generating a key required for mutual authentication and encryption and decryption of the image data after the data frame is transmitted, together with information for distinguishing the image data. Additional information transmission method for copy protection. The method of claim 5, A fifth step of performing authentication and key generation of the counterpart device using the additional data received in the fourth step; And And a sixth step of performing an encryption process of the image data to be transmitted by using the generated key when the counterpart device is authenticated. The method of claim 5, And the segmentation information of the video data and additional data is 1 bit of information. The method of claim 5, The signal transmission and reception between the two devices is an RF signal band, characterized in that the additional information transmission method for copy protection of the video signal. In the device for transmitting and receiving image data, Modulation means for modulating the image data into a digital broadcast format and transmitting the RF data in a designated band; Among the signals in the same band as the video data transmission / reception band, the signal of the band-divided reception band is demodulated by a signal system different from that of the digital broadcasting system, and the data to be transmitted is also modulated by the signal system to be different from the reception band. Additional data modulation and demodulation means for modulating a signal in a transmission / reception band of video data; And Control means for generating copy protection information of the image data and transmitting it through the modulating means, and receiving additional data necessary for encrypting or decrypting the image data through the additional data modulation / demodulation means, and then determining reproduction or transmission of the image data. Apparatus for transmitting additional information for copy protection of a video signal comprising a. In the device for transmitting and receiving image data, Modulation means for modulating the image data and additional data to be transmitted into a data frame of a digital broadcast format and transmitting the RF data of a designated band; Receiving means for receiving and demodulating the signal within the designated band, extracting information designating a frame type from the demodulated data frame, and dividing the received data frame into image data and additional data accordingly; And And controlling means for determining the type of the data frame to be transmitted, adding the data frame to the data frame, and determining reproduction or transmission of the image data based on the additional data separated by the receiving means. Additional information transmission device for. The method of claim 10, And information for determining the type of the data frame is recorded in a field sync area of a data frame of the digital broadcast format. The method of claim 2, In the first step, the additional information transmission method for copy protection of a video signal, characterized by dividing and setting the transmission and reception bands for exchanging additional data in a signal system different from the digital broadcasting method. Transmitting a data frame of a digital broadcast format including copy protection information to a counterpart device; A second step of transmitting and receiving data for mutual authentication with a counterpart device and determining whether to authenticate after transmitting the data frame; And And the third step of generating a key for encrypting and / or decrypting the content, encrypting the content, and transmitting a data frame including the encrypted content and the copy protection information to the counterpart device. Additional information transmission method for signal copy protection. The method of claim 13, In the third step, additional information for copy protection of an image signal, characterized in that the additional data for generating a key required for the encryption and / or decryption of the content is transmitted and received using the transmission and reception band of the divided additional data. Transmission method. The method of claim 14, The third step, the additional information transmission method for copy protection of the image signal, characterized in that for performing the authentication and key generation process of the other device using the data received by the second step. The method of claim 13, The copy protection information is inserted into a field sync (Field Sync) area of the data frame of the digital broadcast format. The method of claim 13, The signal transmission and reception between the two devices is an RF signal band, characterized in that the additional information transmission method for copy protection of the video signal. A first step of receiving a data frame of a digital broadcast format including copy protection information; And After receiving the data frame, transmitting and receiving data for mutual authentication with a counterpart device and receiving a data frame including encrypted content and the copy protection information from the counterpart device when authentication is determined from the counterpart device. The additional information transmission method for copy protection of the video signal is made. The method of claim 18, In the second step, the additional information transmission method for copy protection of a video signal, characterized in that the additional data for generating a key required for encrypting and / or decrypting the content is received from the reception band of the divided additional data. The method of claim 18, The copy protection information is inserted into a field sync (Field Sync) area of the data frame of the digital broadcast format.

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