JP2002281464A - Encryption transmission system - Google Patents

Abstract

(57) [Summary] [PROBLEMS] The reproduction of digital video to which digital audio is added has become widespread in personal computers and the like, and it is demanded that high-quality transmission be performed not only for video but also for audio. It is becoming. Provided is a transmission system that can transmit video information and audio information with high quality. A transmission system that transmits video information and audio information with high quality performs time-division multiplexing of a video signal and an audio signal, and transmits the encrypted data. On the transmitting side, the audio signal is time-axis-compressed, and the time-axis-compressed audio signal is multiplexed and transmitted in a blanking period of the video signal. Control is performed using an audio signal data enable signal ADE and a switching signal between an audio signal and a video signal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an encryption transmission system for encrypting and transmitting digital video and audio signals.

[0002]

2. Description of the Related Art LCD (Liquid Crystal Display Device)
e) When transmitting an analog video signal to a CRT (Cathode Ray Tube) or a CRT (Cathode Ray Tube), blurring or ghosting occurs on the display screen due to waveform distortion or the like. (DVI standard) To solve the above problem, DVI
(Digital Visual Interface) standard, LCD and CR
The video signal to T is transmitted digitally. Thereby, a high quality screen without transmission distortion can be displayed.

[0003] A conventional signal transmission system to which the DVI standard is applied includes a transmission device and a reception device, and the transmission device and the reception device are connected via a transmission path. The transmitting device has three TMDS encoders / serializers, and the receiving device has three TMDS decoders / recoveries. 3 consisting of RED, GREEN, BLUE
Component signals are represented by the corresponding TMDS
Input to the encoder / serializer, each TMDS encoder / serializer converts each component signal to TM
The data is DS-encoded, serialized, and transmitted to a transmission path. Next, each TMDS decoder / recovery of the receiving apparatus decodes the received signal by TMDS, recovers the signal, and restores the component signal.

[0004] The DE (data enable) signal is an RE signal.
This signal indicates a period during which a component signal such as D, GREEN, or BLUE is present, and is active HIGH. For example, the period during which the DE signal is LOW is a horizontal synchronization signal period or a vertical synchronization signal period of a video. C
The TL signal includes CTL0, CTL1, CTL2, CTL
3 is provided as a control signal. Note that the current DV
In the I standard, these signals are unused. Specifically, the signal level is always 0.

[0005] The TMDS encoder / serializer of the transmission device converts a video signal input with 8 bits into 10 bits, serializes the video signal converted into 10 bits, and transmits the serialized video signal to a transmission path. The purpose of converting from 8 bits to 10 bits is to reduce data change points and make the data suitable for high-speed transmission. Further, the TMDS encoder / serializer converts the control signal 2 bits into 10 bits and sends out the control signal to the transmission path. The data enable signal is also encoded and serialized together and transmitted to the transmission path. The TMDS decoder / recovery of the receiving device decodes and expands 10-bit serial data received from the transmission line into 8 bits of a color signal, 2 bits of a data enable signal and 2 bits of a control signal.

(HDCP standard) HDC is a digital content protection system conforming to the DVI standard.
P (High-bandwidth Digital Content Protection Syst
em) Standards have been proposed. The HDCP standard is a standard for transmitting video contents that require copyright protection using a signal transmission system that conforms to the DVI standard. It consists of sharing and encryption of video content on the communication path.

In a signal transmission system to which the HDCP standard is applied, an authentication section for performing authentication and key sharing with a reception apparatus, an encryption section for encrypting video information using a shared key, and a TMDS encoding section in a transmission apparatus. An authentication unit for performing authentication and key sharing with the transmitting device in the receiving device;
It has an S decryption unit and a decryption unit that decrypts a received signal using a shared key.

[0008] With this configuration, after performing authentication and key sharing between the transmitting device and the receiving device via the I ² C bus, the transmitting device encrypts the video RGB data and transmits the video data to the TMDS encoder of the DVI standard. To send over. The receiving device is
After receiving the data via the DVI standard TMDS decryption unit, the encrypted video RGB data is decrypted using the same key as that of the transmitting device to obtain the original video RGB data. According to the HDCP standard, the encryption used here is HDCP Cipher
The core of the HDCP Cipher is common in authentication, key sharing, and video data encryption.

As described above, the DVI standard and HD
In a data transmission system to which the CP standard is applied, a high-quality image can be transmitted while protecting a video on a transmission path as a copyrighted work.

[0010]

In recent years, the reproduction of digital video to which digital audio has been added has become widespread in personal computers, digital broadcast receiving devices, DVD reproducing devices, and the like.
Similar to the above, there is an increasing demand for high quality transmission.

Accordingly, an object of the present invention is to provide a transmission system, a transmission device, a reception device, and a video display device capable of transmitting video information and audio information with high quality in order to meet such demands. .

[0012]

In order to achieve the above object, the present invention comprises a transmitting device for transmitting digital video information with a blanking interval, and a receiving device for receiving the digital video information. Wherein the transmitting device transmits digital audio information during the flyback period, and the receiving device receives the digital audio information during the flyback period.

According to the present invention, there is provided a transmitting apparatus for generating frame information including digital video information with a blanking period, encrypting and transmitting the frame information, and receiving and decrypting the encrypted frame information. And a video display device for extracting and displaying the digital video information from the received frame information, wherein the transmission device multiplexes digital audio information with the frame information during the flyback period. , The digital audio information is multiplexed and transmitted frame information, the video display device,
Receiving the encrypted frame information, generating frame information by decoding, extracting the digital audio information from the flyback period placed in the generated frame information,
It is characterized in that it is converted into an audio signal.

Further, the present invention is a transmitting apparatus for generating, encrypting and transmitting frame information including digital video information at one or more blanking periods, wherein the digital audio information is transmitted during the blanking period. Multiplexing means for multiplexing the digital audio information with the frame information, encryption means for encrypting the frame information in which the digital audio information is multiplexed, and transmission means for transmitting the encrypted frame information. And

Here, the generated frame information is:
A vertical blanking period is provided, and subsequently, a horizontal blanking period is provided for each line to include line video information, the digital audio information is composed of a plurality of line audio information, and the multiplexing unit includes The line audio information may be multiplexed in a flyback period and / or the horizontal flyback period.

Here, the encrypting means includes a frame key generating means for generating a frame key used as an encryption key in accordance with the frame information, and a frame key generating means for generating the frame key in accordance with the frame information. And a frame encryption unit for encrypting digital audio information and digital video information included in the frame information.

Here, the frame encryption unit uses the frame key to encrypt line audio information and line video information included in the frame information, and a key update unit that updates the frame key. Until the encryption of all the line audio information and line video information included in the frame information is completed, the next line audio information and the next line audio information and It may be configured to include control for encrypting the next line video information and repetition control means for controlling the key updating means to update the updated frame key again. .

Here, the frame encryption means may be configured to use the same encryption method in encrypting the digital audio information and the digital video information. Here, the line encryption unit sets an initial value for audio, encrypts line audio information using the set initial value for audio, and then sets an initial value for video having the same value as the initial value for audio. An initial value may be set, and line video information may be encrypted using the set video initial value.

Here, the transmitting device transmits the encrypted frame information to a video display device, and the encrypting means performs authentication of the video display device, generation of the frame key, and generation of the frame information. May be configured to use a common operation module in the encryption. Here, the multiplexing unit further generates a video enable signal indicating transmission of the digital video information in a period including the digital video information in the frame information,
In the flyback period, an audio enable signal indicating transmission of the digital audio information may be generated, and the transmission unit may further be configured to transmit the generated video enable signal and the audio enable signal. .

Here, the multiplexing means generates an audio enable signal indicating transmission of the digital audio information in the vertical retrace period and / or the horizontal retrace period for multiplexing the digital audio information. May be configured. Here, the multiplexing unit generates the frame information using a multiplex control signal for identifying transmission of the digital audio information and the digital video information, and the transmitting unit transmits the multiplex control signal. May be configured.

Here, the multiplexing means may be configured to generate frame information with no signal period between the digital audio information and the digital video information.
The present invention is also a video display device that receives and decrypts the encrypted frame information from the transmitting device, extracts the digital video information from the decrypted frame information, and displays the digital video information. Receiving means for receiving the frame information, decoding means for decoding the encrypted frame information, and extracting digital audio information from the retrace period placed in the decoded frame information, It is characterized by comprising extraction means for extracting digital video information from a period, and output means for displaying the extracted digital video information and converting the extracted digital audio information into an audio signal.

Here, the digital audio information is composed of a plurality of line audio information, and the frame information is provided with a vertical retrace period, followed by a horizontal retrace period for each line. The line audio information is multiplexed in the vertical blanking period and / or the horizontal blanking period, and the extracting means includes the vertical blanking period and / or the horizontal blanking period. , The line audio information may be extracted.

Here, the decryption means uses frame key generation means for generating a frame key used as a decryption key corresponding to the frame information, and the frame key generated corresponding to the frame information. And frame decoding means for decoding digital audio information and digital video information included in the encrypted frame information.

Here, the frame decoding means uses the frame key to decode line audio information and line video information included in the encrypted frame information, and updates the frame key. Key updating means, and until the decoding of all the line audio information and line video information included in the encrypted frame information is completed, the line decoding means uses the updated frame key to And a repetition control unit for controlling the key updating unit to update the updated frame key again. May be.

Here, the frame decoding means may be configured to use the same decoding method in decoding the digital audio information and the digital video information. Here, the line decoding means sets an initial value for audio,
Using the set initial value for audio, decode the line audio information, then set an initial value for video having the same value as the initial value for audio, using the set initial value for video, You may comprise so that line video information may be decoded.

Here, the decryption means may be configured to use a common arithmetic module in authentication by the video display device, generation of the frame key, and decryption of the encrypted frame information. Here, the transmitting unit further receives the video enable signal indicating the transmission of the digital video information and the audio enable signal indicating the transmission of the digital audio information, and the extracting unit further includes: Then, the digital video information may be extracted during a period indicated by the video enable signal, and the digital audio information may be extracted during a period indicated by the audio enable signal.

Here, the receiving means receives a multiplex control signal for identifying transmission of the digital audio information and the digital video information, and the extracting means uses the multiplex control signal to output the digital audio information and the digital audio information. The digital video information may be configured to be extracted. Here, the receiving unit receives the encrypted frame information with a no-signal period between the digital audio information and the digital video information, and the extracting unit includes the digital audio information and the digital audio information. In the no signal period between the video information,
A multiplex control signal for identifying reception of the digital audio information and the digital video information may be generated, and the digital audio information and the digital video information may be extracted using the generated multiplex control signal. .

[0028]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A personal computer system 10 according to one embodiment of the present invention will be described. 1. 1. Configuration of Personal Computer System 10 As shown in FIG. 1, a personal computer system 10 includes a PC (personal computer) main unit 20,
It comprises a CRT display device 30, a keyboard 41 and a mouse 42. PC main unit 20 and CRT
The display device 30 includes the cables 50a and 50b.
Connected by

As shown in FIG. 2, the PC main unit 20 includes a video connection unit 201, a video / audio processing unit 202,
It comprises a VD input / output unit 203, a control unit 204 and other units not shown. The PC main unit 20 includes a microprocessor, a ROM, a RAM, a hard disk unit, and the like, and a computer program is stored in the RAM or the hard disk unit. When the microprocessor operates according to the computer program, P
The C main unit 20 achieves its function.

The CRT display device 30 includes a video connection unit 301, a display control unit 302, and a CRT unit 30.
3. It includes a speaker control unit 304 and a speaker 305. As shown in FIG. 3, the video connection unit 201 includes a multiplexing unit 211, an HDCP encryption unit 215, and a TMD
It comprises an S encoding unit 213. HDCP encryption unit 21
5 includes an encryption unit 212 and an authentication key sharing unit 214. Also, as shown in FIG.
S decoding section 311, HDCP decoding section 315, and separation section 31
3 The HDCP decryption unit 315 includes the encryption unit 3
12 and an authentication key sharing unit 314.

The DVD records coded video / audio information composed of coded video information obtained by compression-coding video information and coded audio information obtained by compression-coding audio information. An example of the video / audio information is movie information composed of a moving image and audio information. The DVD is mounted on the DVD input / output unit 203 by a user. The PC main unit 20 reads the DVD mounted on the PC main unit 20 from the DVD.
The coded video / audio information is read, and the read coded video / audio information is separated to generate coded video information and coded voice information. Next, the encoded video information is decoded to generate decoded video information. Here, the decoded video information and the encoded audio information are digital signals. Next, the PC main unit 2
0 generates encrypted video information and encrypted audio information by respectively encrypting the decrypted video information and the encoded audio information, and transmits the generated encrypted video information and the encrypted audio information to the cable 5.
0a to the CRT display device 30. The CRT display device 30 receives the encrypted video information and the encrypted audio information, decodes the received encrypted video information and the encrypted audio information, and generates and generates the decoded video information and the decoded audio information. The decoded video information is displayed on the CRT unit 303, the generated decoded audio information is converted into an analog audio signal, and output from the speaker 305.

1.1 Keyboard 41, Mouse 42, Control Unit 204, DVD Input / Output Unit 203, and Video / Audio Processing Unit 202 The keyboard 41 and mouse 42
An input of an instruction to reproduce the encoded video / audio information recorded in the VD is received, instruction information corresponding to the received instruction is generated, and the generated instruction information is transmitted to the control unit 20.
Output to 4.

The control unit 204 receives the instruction information, and outputs a read instruction of the encoded video / audio information to the DVD input / output unit 203 based on the received instruction information.
The DVD input / output unit 203 receives the read instruction, reads the encoded video / audio information from the DVD based on the received read instruction, and outputs the read encoded video / audio information to the video / audio processing unit 202. .

The video / audio processing unit 202 receives the coded video / audio information, separates the received coded video / audio information, generates coded video information and coded voice information, and generates the generated coded video / audio information. It decodes the video information to generate decoded video information, and outputs the generated decoded video information and the generated coded audio information to the video connection unit 201. 1.2 Video Connection Unit 201 (1) Multiplexing Unit 211 The multiplexing unit 211 receives the decoded video information and the encoded audio information from the video / audio processing unit 202.

The decoded video information includes a plurality of pieces of frame video information corresponding to one frame. By displaying the plurality of frame video information continuously, a moving image is represented on the CRT display device 30. Each frame image information includes 480 line image information corresponding to one line. Further, the encoded audio information includes frame audio information corresponding to the frame video information. The frame audio information is converted into audio and output during the time zone in which the corresponding frame video information is reproduced by the CRT display device 30. Each frame audio information includes 480 line audio information corresponding to the line video information.

The multiplexing unit 211 converts one frame of video information among the decoded video information
When transmitting to the RT display device 30, between the PC main unit 20 and the CRT display device 30,
In order to establish synchronization for displaying the frame video information, a vertical retrace period including a time at which a predetermined number of vertical synchronization signals are transmitted is provided immediately before the transmission of the frame video information. Next, in order to establish synchronization for displaying each line image information in one frame image information, immediately before each line image information is transmitted, a horizontal return including a time at which a horizontal synchronization signal is transmitted is included. A line period is provided.

FIG. 4 shows the relationship between the vertical blanking period, the horizontal blanking period, and one frame of video information. As shown in this figure, each frame video information is composed of 480 line video information, and each line video information is composed of 720 pixels. Each pixel is composed of 24 bits, and each pixel includes RED, GREEN, and BLUE component information of 8 bits each. As shown in this figure, the multiplexing unit 211 provides a time zone corresponding to the transmission of 45 line video information as a vertical retrace period immediately before transmitting one frame video information. Next, immediately before transmitting each line video information,
A time zone corresponding to the transmission of 138 pixels is provided as a horizontal retrace period.

As shown in FIG. 5, the multiplexing section 211 converts a video signal data enable signal DE at the start of the vertical blanking period for one frame of video information among the received decoded video information. LOW is set, the data enable signal ADE for the audio signal is set to LOW, and the data enable signals DE and ADE set to LOW are output to the TMDS encoding unit 213.

Next, as described later, when the HDCP encryption unit 215 completes the calculation of the frame key during the vertical blanking period, the data enable signal ADE for the audio signal is set to HIGH from this time, The data enable signal ADE set to HIGH is transmitted to the TMDS encoder 2
13 is output. At this point, the output of the encoded audio information is started.

FIG. 5 shows data enable signals DE and AD in a time zone in which one frame of video information is transmitted.
E, temporal changes in decoded video information and coded audio information. In this figure, time elapses from the left end of the line 401 toward the right end. Subsequently, the line 402 passes from the left end to the right end. Hereinafter, line 40
3, 404,..., 405.

The time zones indicated by the lines 401, 402,..., 403 are the vertical blanking periods. Line 401
In the time zone indicated by, the multiplexing unit 211 sets the data enable signal DE to LOW and sets the data enable signal ADE to LOW. In this time zone, the decoded video information and the encoded audio information are not output. Also, at the start of the time period indicated by the line 401, H
The calculation of the frame key by the DCP encryption unit 215 is started.

At the start of the time period indicated by the line 402, the multiplexing unit 211 sets the data enable signals DE and ADE to LOW as described above. Next, assuming that the above-described calculation of the frame key by the HDCP encryption unit 215 is completed within the time zone indicated by the line 402, the data enable signal ADE for the audio signal is set to HIGH from this completion point and set to HIGH. The output data enable signal ADE is output to the TMDS encoder 213. At this point, the output of one piece of audiovisual information is started.

From the line following the line 402 to the line 40
3, the multiplexing unit 211 sets the data enable signal DE to LOW, sets the data enable signal ADE for the audio signal to HIGH, and sets the data enable signals DE and ADE to the TMDS encoding unit 21.
Output to 3. Further, the multiplexing unit 211 continuously
The output of line video information continues.

Next, in the time zone shown by the line 404, the multiplexing unit 211
Sets the data enable signal DE to LOW,
The data enable signal DE set to W is output to the TMDS encoder 213. Next, for a period of one line of video information starting immediately after the end of the horizontal retrace period,
The multiplexing unit 211 sets the data enable signal DE to HIGH.
And outputs the data enable signal DE set to HIGH to the TMDS encoder 213.

In the time period indicated by the line 404, the multiplexing unit 211 sets and outputs the data enable signal ADE for the audio signal to HIGH during the horizontal retrace period, and continues the one line audio information. And encryption part 2
12 is output. Here, lines 402 to 404
One line audio information continuously output at is
It is composed of a number of voice cells determined by the time when the HDCP encryption unit 215 completes the calculation of the frame key. Each voice cell is composed of 24-bit coded voice information. The multiplexing unit 211 outputs one piece of line video information to the encryption unit 212 in a period of one piece of line video information starting immediately after the end of the horizontal retrace period. One piece of line video information is composed of 720 pixels.

FIG. 6 shows the relationship among the data enable signals DE and ADE, the coded audio information, and the decoded video information in each time zone shown from the line following the line 404 to the line 405. As shown in FIG.
Outputs one line of audio information to the encryption unit 212 during the horizontal retrace period. Here, one line audio information is composed of 138 audio cells. Each voice cell is composed of 24-bit coded voice information. The multiplexing unit 211 outputs one piece of line video information to the encryption unit 212 in a period of one piece of line video information starting immediately after the end of the horizontal retrace period. One piece of line video information is composed of 720 pixels.

The multiplexing unit 211 generates the predetermined number of vertical synchronization signals VSYNC during the vertical blanking period, and outputs the generated vertical synchronization signals VSYNC to the TMDS encoding unit 213. In addition, within a horizontal retrace period, a horizontal synchronization signal HSYNC is generated, and the generated horizontal synchronization signal HSYNC is output to the TMDS encoding unit 213.

(2) Authentication Key Sharing Unit 214 The authentication key sharing unit 214 operates according to the HDCP standard. The main operations of the authentication key sharing unit 214 include device authentication between the authentication key sharing unit 214 and the receiving device, key sharing, generation of a random number for encryption, and the like. Authentication key sharing unit 214
The details of are described in the HDCP standard, and will not be described.

The authentication key sharing unit 214 is connected to an authentication key sharing unit 314 to be described later via a cable 50b which is an I ² C bus.
Is connected to The specific function and configuration of the authentication key sharing unit 214 in the present embodiment will be described later. (3) Encryption Unit 212 The encryption unit 212 receives a pixel and a voice cell from the multiplexing unit 211 and a random number PRj from the authentication key sharing unit 214 for each operation clock.

Next, when a pixel is received, the encryption unit 2
12, the received pixel and the random number PR
j and an exclusive OR for each bit to generate an encrypted pixel, and the generated encrypted pixel is transmitted to the TMDS encoder 213.
Output to (Equation 1) Encrypted pixel = pixel (+) random number PRj Here, the operator (+) indicates exclusive OR.

Similarly, when a voice cell is received, the encryption unit 212 performs an exclusive OR operation on the received voice cell and the random number PRj for each bit, as shown in Expression 2, to perform encryption. A voice cell is generated, and the generated encrypted voice cell is output to the TMDS encoding unit 213. (Equation 2) Encrypted voice cell = voice cell (+) random number PRj (4) TMDS encoding section 213 The TMDS encoding section 213 transmits
It is connected to a TMDS decoding unit 311 described below.

As shown in FIG. 7, the TMDS encoder 213 includes a TMDS encoder / serializer 213a,
13b and 213c. TMDS encoder serializers 213a, 213b and 213c
Are connected to TMDS decoder / recoveries 311a, 311b and 311c described later via channels C12, C11 and C10 in the cable 50a, respectively, as shown in FIG.

(TMDS encoder / serializer 21
3a) The TMDS encoder / serializer 213a
The RED component information of the encrypted pixels and the first 8 bits of the audio cell are received from the encryption unit 212.
Further, it receives a data enable signal DE for a video signal, a data enable signal ADE for an audio signal, and other control signals from the multiplexing unit 211.

TMDS encoder / serializer 213
a, TMDS-encodes the received 8-bit RED component information, the first 8 bits [23:16] of the voice cell, the data enable signal DE, the data enable signal ADE, and other control signals, and serializes the channel C12. Via the TMDS decoder / recovery 311a.

Specifically, the TMDS encoder / serializer 213a converts the 8-bit RED component information and the leading 8 bits [23:16] of the voice cell into 10-bit information, and serializes the 10-bit information. And send it out. The conversion from 8 bits to 10 bits is performed in order to reduce data change points and to make the data suitable for high-speed transmission. Also, TMD
The S encoder / serializer 213a outputs data enable signals DE and AD which are 2-bit control signals.
E is converted into 10 bits and transmitted.

(TMDS encoder / serializer 21
3b) The TMDS encoder / serializer 213b
From the encryption unit 212, the GREEN component information of the encrypted pixels and the central 8 bits of the voice cell [15:
8]. Further, it receives a data enable signal DE for video signals and other control signals from the multiplexing unit 211.

TMDS encoder / serializer 213
b transmits the received GREEN component information, the center 8 bits [15: 8] of the voice cell, the data enable signal DE, and other control signals in the same manner as described above.
The data is DS-encoded, serialized, and transmitted to the TMDS decoder / recovery 311b via the channel C11.

(TMDS encoder / serializer 21
3c) The TMDS encoder / serializer 213c
The encryption unit 212 receives the BLUE component information of the encrypted pixels and the last 8 bits [0: 7] of the voice cell. Further, it receives a data enable signal DE, a vertical synchronization signal VSYNC, and a horizontal synchronization signal HSYNC for a video signal from the multiplexing unit 211.

TMDS encoder / serializer 213
c is the received BLUE component information, the last 8 bits [0: 7] of the voice cell, the data enable signal DE, the vertical synchronization signal VSYNC, and the horizontal synchronization signal HSY.
Similarly, the NC is TMDS-encoded, serialized, and transmitted to the TMDS decoder / recovery 311c via the channel C10.

1.3 Video Connection Unit 301 (1) TMDS Decoding Unit 311 The TMDS decoding unit 311
It comprises decoder recovery 311a, 311b and 311c. (TMDS decoder recovery 311a) TMDS decoder recovery 311a
The serial data is received from the TMDS encoding unit 213, and 8-bit RED component information and the first 8 bits [23:
16], decodes the data enable signal DE, the data enable signal ADE, and other control signals to obtain the RED component information and the first 8 bits of the voice cell [23:
16] to the encryption unit 312, and outputs the data enable signal DE, the data enable signal ADE, and other control signals to the separation unit 313.

(TMDS decoder recovery 311b)
The TMDS decoder recovery 311b uses the channel C1
1 and receives serial data from the TMDS encoder 213, and executes GREE from the received serial data.
The N component information and the central 8-bit [15: 8] of the voice cell are decrypted, and the GREEN component information and the central 8-bit [15: 8] of the voice cell are encrypted.
12 is output.

(TMDS decoder recovery 311c)
The TMDS decoder recovery 311c uses the channel C1
0, and receives serial data from the TMDS encoding unit 213, and calculates BLUE from the received serial data.
Component information, the last 8 bits of the voice cell [7:
0], the vertical synchronization signal VSYNC and the horizontal synchronization signal HSY
NC, and outputs the BLUE component information and the last 8 bits [7: 0] of the voice cell to the encryption unit 312,
The vertical synchronization signal VSYNC and the horizontal synchronization signal HSYNC are output to the display control unit 302.

(2) Authentication Key Sharing Unit 314 Like the authentication key sharing unit 214, the authentication key sharing unit 314
It operates according to the HDCP standard. The main operation of the authentication key sharing unit 314 is device authentication, key sharing, generation of a random number for encryption, and the like between the authentication key sharing unit 314 and the transmitting apparatus. For details of the authentication key sharing unit 314, see HDC
The description is omitted because it is defined in the P standard.

The specific function and configuration of authentication key sharing section 314 in the present embodiment will be described later. (3) Encryption Unit 312 The encryption unit 312 operates similarly to the encryption unit 212. The encryption unit 312 outputs the TMDS decryption unit 311 for each operation clock.
, And the random number PRj from the authentication key sharing unit 314.

Next, when receiving the encrypted pixel, the encryption unit 312 performs an exclusive OR operation on the received encrypted pixel and the random number PRj for each bit as shown in Expression 3, and
A decoded pixel is generated, and the generated decoded pixel is output to the separation unit 313. (Equation 3) Decoded pixel = encrypted pixel (+) random number PRj Here, the random number used when the encrypted pixel is generated in Expression 1 and the random number used when the decrypted pixel is generated in Expression 3 Since the obtained random number has the same value, the original pixel is decoded.

Similarly, when an encrypted voice cell is received, the encryption unit 312 performs an exclusive OR operation on the received encrypted voice cell and the random number PRj for each bit, as shown in Expression 4. Then, a decoded voice cell is generated, and the generated decoded voice cell is output to the separating unit 313. (Formula 4) decrypted voice cell = encrypted voice cell (+) random number PRj Here, the random number used when generating the encrypted voice cell in Equation 2 and the decrypted voice cell are generated in Equation 4 Since the random number used at the time of decoding has the same value, the original voice cell is decoded.

(4) Separating Unit 313 The separating unit 313 receives 24-bit information from the encrypting unit 312 for each operation clock, and outputs the TMDS decrypting unit 311
Receives the data enable signal DE and the data enable signal ADE. When the received data enable signal DE is HIGH, the separating unit 313 receives the received 2
The 4-bit information is regarded as a decoded pixel, and the received 24-bit information is output to the display control unit 302 as a decoded pixel for each operation clock. Further, the separation unit 313 outputs the received data enable signal DE to the display control unit 302.

When the received data enable signal ADE is HIGH, the separating unit 313 receives the received 2
The 4-bit information is regarded as a decoded voice cell, and the received 24-bit information is output to the speaker control unit 304 as a decoded voice cell for each operation clock. Further, separation section 313 outputs the received data enable signal ADE to speaker control section 304.

1.4 Display Control Unit 302 and C
RT unit 303 The display control unit 302 receives the decoded pixel and the data enable signal DE for each operation clock from the separation unit 313, and receives the vertical synchronization signal VS from the TMDS decoding unit 311.
It receives the YNC and the horizontal synchronization signal HSYNC. The display control unit 302 receives the decoded pixel, the data enable signal DE, and the vertical synchronization signal VS received for each operation clock.
Based on YNC and horizontal synchronization signal HSYNC, RE
Generate D, GREEN and BLUE analog signals,
The generated analog signals are output to the CRT unit 303.

The CRT unit 303 includes a display control unit 3
02 receives the analog signals of RED, GREEN and BLUE and displays a color image. 1.5 Speaker Control Unit 304 and Speaker 305 The speaker control unit 304 receives the decoded voice cell and the data enable signal ADE from the separation unit 313 for each operation clock, and sets the received data enable signal ADE to H
During IGH, the received decoded voice cell is decoded to generate voice information, the generated voice information is converted to generate an analog signal, and the generated analog signal is output to the speaker 305.

The speaker 305 includes a speaker control unit 304
And converts the received analog signal to generate and output audio. 2. Operation of Personal Computer System 10 The operation of the personal computer system 10 will be described. (1) Outline Operation of Personal Computer System 10 Outline operation of the personal computer system 10 when reproducing encoded video / audio information recorded on a DVD in accordance with a user's instruction will be described with reference to the flowchart shown in FIG. I do.

In accordance with the HDCP standard, a PC is connected between the PC main unit 20 and the CRT display device 30.
The main device 20 authenticates whether the CRT display device 30 is a valid device (step S101), and ends the process if the authentication fails (step S102). If the authentication is successful (step S102), the HD
A KSV list is generated based on the CP standard (Step S103). Here, regarding the generation of the KSV list,
The description is omitted because it is described in the HDCP standard.

Next, a value of 0 is set to a variable i indicating a frame number (step S104). Next, step S
In steps 105 to S112, the processing shown in steps S105 to S111 is repeated for each frame. The value of 1 is added to the variable i (step S106), and key sharing is performed for each frame (step S107). Next, step S1
From 08 to S111, step S1
Steps S09 to S110 are repeated.

The encryption, transmission and decryption of one line audio information and one line video information are performed (step S10).
9) The key is updated based on the HDCP standard (step S110). (2) Operation of Device Authentication The operation of device authentication shown in step S101 of FIG. 8 will be described with reference to the flowchart shown in FIG. Since the device authentication is described in the HDCP standard, a detailed description is omitted.

The authentication key sharing unit 214 generates An (step S171), and transmits An and Aksv to the authentication key sharing unit 314 via the cable 50b, which is an I ² C bus (step S172). The authentication key sharing unit 314
The sv and the REPEATER are transmitted to the authentication key sharing unit 214 via the cable 50b that is an I ² C bus (step S173).

The authentication key sharing unit 214 determines that Km = Akeys
Over Bksv is calculated (step S174),
(K _s , M ₀ , R ₀ ) = dviBlkCipher
(Km, REPEATER || An) is calculated (step S175). The authentication key sharing unit 314 calculates Km ′ = Bk
Eys over Aksv is calculated (step S17).
_{6), (K s',} M 0 ', R 0') = dviBlkC
Ifer (Km ′, REPEATER || An) is calculated (step S177), and R ₀ ′ is transmitted to the authentication key sharing unit 214 via the cable 50b that is an I ² C bus (step S178).

The authentication key sharing unit 214 compares R ₀ and R ₀ ′, and if they match (step S 179),
The RT display device 30 is authenticated as a legitimate device. If they do not match (step S179),
It authenticates that the CRT display device 30 is not a valid device. (3) Operation of Key Sharing for Each Frame The operation of key sharing for each frame shown in step S107 in FIG. 8 will be described with reference to the flowchart shown in FIG. Since the key sharing for each frame is described in the HDCP standard, a detailed description is omitted.

The authentication key sharing unit 214 determines (Ki, Mi, R
i) = dviBlkCipher (Ks, REPEAT
ER || M _i-1 ) is calculated (step S131). Next, the authentication key sharing unit 214 determines that Ri = ri only when (i mod 128) is 0 (step S132).
Is calculated (step S133). Authentication key sharing unit 314
Is (Ki ', Mi', Ri ') = dviBlkCip
Her (Ks', REPEATER || M'i _-1 ) is calculated (step S141). Next, the authentication key sharing unit 31
No. 4 calculates Ri ′ = ri ′ only when (i mod 128) is 0 (step S142) (step S143). Next, the authentication key sharing unit 314 transmits the Ri ′ to the authentication key sharing unit 214 via the cable 50b, which is an I ² C bus, every two seconds.
Compares Ri and Ri ′ every two seconds, and if they match (step S135), the CRT display device 3
0 is authenticated as a valid device. If they do not match (step S135), it authenticates that the CRT display device 30 is not a legitimate device.

(4) Encrypting, transmitting and decrypting operations of one line audio information and one line video information One line audio information and one line video information encryption shown in step S109 in FIG. The operations of conversion, transmission and decoding will be described with reference to the flowchart shown in FIG.

The authentication key sharing unit 214 temporarily stores an initial value used for generating a random number defined in the HDCP standard as a stored initial value. Here, the initial value is specifically Mi _-1 . (Step S20
0). Next, in steps S201 to S205, the following steps S202 to S204 are repeated for each audio cell ACj in one piece of line audio information.
Here, one line audio information includes 138 audio cells. The variable j is:
It takes a value from 1 to 138.

The authentication key sharing unit 214 generates a 24-bit random number PRj (step S202), and the encryption unit 212
Performs an exclusive OR operation on the voice cell ACj and the random number PRj to generate an encrypted voice cell EACj (step S20).
3). Next, the encryption unit 212 converts the TMDS encoding unit 21
3, via the cable 50a and the TMDS decoding unit 311
The generated encrypted voice cell EACj is transmitted to the encryption unit 312 (step S204).

The authentication key sharing unit 314 temporarily stores an initial value used for generating a random number defined in the HDCP standard as a stored initial value. Here, the initial value is specifically M ′ _i−1 . (Step S22
1). Next, in steps S222 to S225, each encrypted voice cell DA in one line voice information is
For Cj, the following steps S223, S204, S
Repeat 224. Here, 138 encrypted voice cells are included in one line voice information. The variable j is
In the above repetition, values of 1 to 138 are taken.

The authentication key sharing unit 314 generates a 24-bit random number PRj (step S 223), and
Performs an exclusive OR operation on the encrypted voice cell DACj and the random number PRj to generate a decrypted voice cell DACj.
2 outputs the generated decoded speech cell DACj to the separation unit 313 (step S224). Authentication key sharing unit 214
Restores the initial value from the stored initial value (step S206). Next, from step S207
In S211, each pixel P in one line video information
The following steps S208 to S210 are repeated for Cj. Here, in one line video information, 720
Pixels. The variable j takes a value of 1 to 720 in the above repetition.

The authentication key sharing unit 214 generates a 24-bit random number PRj (step S208), and the encryption unit 212
Performs an exclusive OR operation on the pixel PCj and the generated random number PRj to generate an encrypted pixel EPCj (step S20).
9), the encryption unit 212 transmits the encryption unit 3 via the TMDS encoding unit 213, the cable 50a, and the TMDS decoding unit 311.
12, the generated encrypted pixel EPCj is transmitted (step S210).

The authentication key sharing unit 314 restores the initial value from the stored initial value (Step S22)
6). Next, in steps S227 to S230, 1
The following steps S228, S210, and S229 are repeated for each encrypted pixel DPCj in the pieces of line video information. Here, in one line video information, 720
Encrypted pixels are included. The variable j takes a value of 1 to 720 in the above repetition.

The authentication key sharing unit 314 generates a 24-bit random number PRj (step S228), and the encryption unit 312
Performs an exclusive OR operation on the encrypted pixel DPCj and the generated random number PRj to generate a decoded pixel DPCj, and outputs the generated decoded pixel DPCj to the separation unit 313 (step S229). (5) HDCP encryption unit 215 [HDCP decryption unit 315]
State transition of encryption [decryption] by the HDCP encryption unit 215 [HDCP decryption unit 315] will be described with reference to FIG. Here, the description in [] is HDCP
26 illustrates a state transition of decoding by the decoding unit 315.

(Transition from Any State to Idle State D0) When in Reset State (Step S30)
1) or when authentication fails (step S30)
4), HDCP encryption unit 215 [HDCP decryption unit 315]
Transitions to the idle state D0. (Transition from Idle State D0 to Frame Key Calculation State D1) HDCP Encryption Unit 215 [HDCP Decryption Unit 315]
Uses the CTL3 signal, which is not used in the DVI standard, based on the HDCP standard as a synchronization signal for frame key calculation. When the authentication is successful and when the CTL3 signal of the DVI interface is generated (step S30)
2), HDCP encryption unit 215 [HDCP decryption unit 315]
Makes a transition to a frame key calculation state D1 in which frame key calculation is performed. In the frame key calculation state D1, the HDCP
The encryption unit 215 [HDCP decryption unit 315] calculates a frame key used for encryption [decryption] of the next video frame.

(Transition from Frame Key Calculation State D1 to Video Encryption [Decryption] State D2) During the V blank period, when there is no audio signal start signal, the head of the video signal to be encrypted [decrypted] is given. Upon receiving the DE signal (step S
309), HDCP encryption unit 215 [HDCP decryption unit 31
5] makes a transition to the video encryption [decryption] state D2. In the video encryption [decryption] state D2, the HDCP encryption unit 21
5 [HDCP decryption section 315] encrypts [decrypts] the video signal.

(Unknow from video encryption [decryption] state D2
(Transition to n Blank state D3) The end of the video signal (generally the end of a row or the end of a frame) is notified by DE.
In FIG. 12, this signal is expressed as “! DE”. ! Upon receiving the DE (step S308), the HDC
The P encryption unit 215 [HDCP decryption unit 315]
Transition to the Blank state D3. In the Unknown Blank state D3, the HDCP encryption unit 215 [HDCP decryption unit 315]
Starts a key update.

(Transition from Unknown Blank State D3 to Frame Key Calculation State D1) When the CTL3 signal is received in the Unknown Blank state D3 (step S303),
The HDCP encryption unit 215 [HDCP decryption unit 315] performs a frame key calculation state D for performing a new video frame key calculation.
Transitions to 1. (Transition from Unknown Blank State D3 to H Blank State D4) Hsync indicates that it is an H blank (generally between lines). Upon receiving the Hsync (step S310), the HDCP encryption unit 215 [HD
CP decoding unit 315] transitions to the H blank state D4.

In the H blank state D4, the key update
If the Unknown Blank state is not completed in step 3, the HDCP encryption unit 215 [HDCP decryption unit 315] waits here.
(Transition from Unknown Blank state D3 to V blank state D5) Vsync indicates that there is a V blank (generally between frames). Upon receiving Vsync (step S318), the HDCP encryption unit 215 [HDCP decryption unit 315] transitions to the V blank state D5.

(Transition from H Blank State D4 to Video Encryption [Decryption] State D2) When there is no audio signal during the H blanking period, a DE signal is received (step S31).
4), HDCP encryption unit 215 [HDCP decryption unit 315]
Starts the encryption [decryption] of the next row of the video signal, and transitions to the video encryption [decryption] state D2. (Transition from H blank state D4 to frame key calculation state D1) If CTL3 signal is generated (step S31)
5), HDCP encryption unit 215 [HDCP decryption unit 315]
Makes a transition to a frame key calculation state D1 in which a new frame key calculation is performed.

(Transition from H Blank State D4 to V Blank State D5) It can be seen from Vsync that it is a V blank. When receiving Vsync (step S31)
6), HDCP encryption unit 215 [HDCP decryption unit 315]
Transitions to the V blank state D5. V blank state D
5, the HDCP encryption unit 215 [HDCP decryption unit 3
15] waits for an end condition.

(Transition from V Blank State D5 to Frame Key Calculation State D1) When a CTL3 signal is generated (step S317), the HDCP encryption unit 215 [HDCP decryption unit 315] calculates a new frame key. The state transits to the frame key calculation state D1. (Transition from V blank state D5 to idle state D0)
During the V blank period, before the CTL3 signal occurs, D
When returning to the video signal by the E signal (step S31)
9), HDCP encryption unit 215 [HDCP decryption unit 315]
Does not encrypt the next frame. This is caused by authentication failure on the link.

(Transition from Frame Key Calculation State D1 to Voice Encryption [Decryption] State D6) During the V blank period, if there is a voice signal start signal ADE (step S305), H
The DCP encryption unit 215 <HDCP decryption unit 315> starts encryption [decryption] of the audio signal. In the audio encryption [decryption] state D6, the HDCP encryption unit 215 [HDCP decryption unit 315] encrypts [decrypts] the audio signal.

(Transition from Audio Encryption [Decryption] State D6 to Video Signal Waiting State D7) When the end of the audio signal is notified by the ADE (step S306), the HDCP encryption unit 215 [HDCP decryption unit 315] Transition is made to a video signal waiting state D7 for waiting for the video signal to start. In FIG. 12, this signal is expressed as “! ADE”.

(Transition from Video Signal Waiting State D7 to Video Encryption [Decryption] State D2) The DE signal of the TMDS link gives the head of the video signal to be encrypted [decrypted]. Upon receiving the DE signal (step S307), the HDCP encryption unit 2
15 [HDCP decryption unit 315] performs video encryption [decryption].
Transition to the state D2. (Transition from H blank state D4 to voice encryption [decryption] state D8) The ADE signal is received (step S311), and the HDCP encryption unit 215 [HDC
The P decryption unit 315] transitions to the audio encryption [decryption] state D8 to start encryption [decryption] of the audio signal in the next H blanking period.

In the voice encryption [decryption] state D8, H
The DCP encryption unit 215 [HDCP decryption unit 315] encrypts [decrypts] the audio signal. (Transition from Audio Encryption [Decryption] State D8 to Video Signal Waiting State D9) When the end of the audio signal is notified by the ADE (step S312),
The HDCP encryption unit 215 [HDCP decryption unit 315] transitions to the video signal waiting state D9.

In the video signal waiting state D9, the HDCP encryption unit 215 [HDCP decryption unit 315] waits for the video signal to start. (Transition from Video Signal Waiting State D9 to Video Encryption [Decryption] State D2) The DE signal of the TMDS link gives the head of the video signal to be encrypted [decrypted]. DE
Upon receiving the signal (step S313), the HDCP encryption unit 215 [HDCP decryption unit 315] transitions to the video encryption [decryption] state D2.

3. Conclusion According to the present embodiment described above, the encryption transmission system that performs time-division multiplexing of the video signal and the audio signal and performs encryption transmission on the transmission side, compresses the audio signal on the time axis, and converts the time-axis-compressed audio signal. Multiplexed during the blanking period of the video signal and transmitted in an encrypted manner.

Further, in the encryption transmission system, the transmitting side calculates a key for a frame after authentication of the receiving side and after the vertical synchronization signal, and performs time-compression using the calculated key for the frame. Encrypts the signal, then encrypts the video signal, further updates the key, encrypts the next time compressed audio signal using the updated key after the horizontal synchronization signal, and then encrypts the next video signal To encrypt.

In the encryption transmission system, the receiving side calculates a key for a frame after authentication with the transmitting side and after a vertical synchronization signal, and encrypts the key using the calculated key for the frame. Decrypted audio signal, then decrypted the encrypted video signal, and further updated the key,
After the horizontal synchronization signal, the next encrypted audio signal is decrypted using the updated key, and then the next encrypted video signal is decrypted.

In the encryption transmission system, the transmitting side notifies the receiving side of the encrypted transmission of the audio signal with the audio signal enable signal and notifies the receiving side of the encrypted transmission of the video signal with the video signal enable signal. On the other hand, on the receiving side, when there is an audio signal enable signal, the audio signal is decoded, and when there is a video signal enable signal,
Decodes video signals.

As described above, in the above-mentioned encryption transmission system, in addition to the data enable signal (DE signal) of the video signal in the conventional example, the data enable signal (ADE signal) of the audio signal is added and the multiplex control signal is transmitted. Control. Since this signal is added, processing corresponding to the transmitting side can be performed on the receiving side even when there is no multiplexing of audio signals.

Further, the encryption transmission system uses the same encryption method for encrypting the video signal and encrypting the audio signal on each of the transmission side and the reception side. Further, when the encryption system has an internal state, the encryption transmission system sets a certain initial state to encrypt the audio signal, and then returns the internal state of the encryption system to the original initial state, and Encrypt the video signal.

HDCP Ciph used in HDCP
“er” is a type of encryption system in which the internal state is held and the input data is encrypted depending on the internal state and the internal state is changed at the same time. On the transmitting side, the internal state of the encryption method at the time of state D3 is stored, and the audio signal is processed (state D3).
8) After that, the internal state saved at the time of the state D9 is restored, and the next video signal is encrypted (state D2). As a result, even if the receiving side can process only the video signal, the internal state of the encryption method on the transmitting side and the receiving side at the time of decoding the video signal is the same (that is, the state is the state). Transition from D9 to state D2;
(Transition from state D4 to state D2), the HDCP receiver can correctly process the video signal.

Further, the cryptographic transmission system uses a common operation module in authentication and key calculation, video signal encryption and audio encryption in each of the transmitting side and the receiving side. As described above, the cryptographic transmission system uses the same cryptographic algorithm for the audio signal and the video signal, so that an additional part from the conventional cryptographic transmission system can be minimized. Further, similar to HDCP, a common operation module is used for authentication, key sharing, and encryption, so that the implementation scale can be reduced.

[0108] In the encryption transmission system, the transmitting side multiplexes the video signal and the audio signal using a multiplexing control signal, while the receiving side multiplexes the multiplexing control signal sent from the transmitting side. To separate it.
Further, according to the present embodiment, the multiplex control signal is transmitted from the transmission side to the reception side. It is also possible to switch between the audio signal and the video signal by recognizing this on the receiving side. In this way, instead of sending the multiplex control signal from the transmitting side to the receiving side, the cryptographic transmission system provides a non-signal period at the switching between the audio signal and the video signal, and recognizes this at the receiving side. To generate a multiplex control signal.

As described above, according to the present embodiment, H
By minimizing the state transition and the implementation scale of the DCP standard, not only a conventional video signal but also a time-axis-compressed audio signal can be multiplexed and encrypted and transmitted during the blanking period. An audio signal switching unit is added to the conventional HDCP standard, and control is performed using an audio signal enable signal and an audio signal switching signal. With this control, the same processing as the conventional HDCP standard can be performed when the audio signal is not multiplexed. If it is difficult to add a switching signal, a non-signal section having a specific length may be provided on the data signal so that the receiving unit detects and switches.

Also, while maintaining upward compatibility with the conventional HDCP standard, this can be extended to the minimum in terms of the standard and implementation, and the audio signal can be encrypted and transmitted together with the video signal.
Further, the encrypted video signal can be decrypted and reproduced even in a receiver conforming to the conventional HDCP standard. Further, by using the same encryption scheme as that for the video signal for encrypting the audio signal, the number of additional modules is minimized, and compact mounting is possible. After encryption of the audio signal in each line,
By returning the internal state of the encryption method to the initial state of each line, the conventional HDCP that the receiver does not support the extended specification
Even if it can only decode a video signal of a standard, that is, a video signal, the video signal can be correctly decoded.

[0111] 4. Other Embodiments Although the present invention has been described based on the above-described embodiment, it is needless to say that the present invention is not limited to the above-described embodiment. The following cases are also included in the present invention. (1) According to the present embodiment, the present invention is realized by a personal computer, but the present invention is not limited to this. A digital video to which digital audio is added may be reproduced in a digital broadcast receiving device, a DVD reproducing device, or the like.

(2) According to the present embodiment, the coded audio information is transmitted from the video connection unit 201 to the video connection unit 301 via all of the channels C12, C11 and C10. Reduce the amount of information transmitted, via one or only two of said channels,
It may be transmitted. Also, according to the present embodiment,
Although the coded audio information is transmitted from the video connection unit 201 to the video connection unit 301 in the vertical retrace period and the horizontal retrace period, it may be transmitted only in the vertical retrace period. Also, only during the horizontal retrace period,
It may be transmitted.

(3) The present invention may be the method described above. Further, these methods may be a computer program that is realized by a computer, or may be a digital signal formed by the computer program. Further, the present invention provides a computer-readable recording medium for the computer program or the digital signal, for example, a flexible disk,
Hard disk, CD-ROM, MO, DVD, DVD
-It may be recorded on a ROM, DVD-RAM, semiconductor memory, or the like. Further, the present invention may be the computer program or the digital signal recorded on these recording media.

Further, in the present invention, the computer program or the digital signal may be transmitted via an electric communication line, a wireless or wired communication line, a network represented by the Internet, or the like. The present invention may also be a computer system including a microprocessor and a memory, wherein the memory stores the computer program, and the microprocessor operates according to the computer program.

Further, by recording the program or the digital signal on the recording medium and transferring it, or by transferring the program or the digital signal via the network or the like, an independent computer system is provided. May be implemented. (4) The above embodiments and the above modifications may be combined.

(Possibility of Industrial Use) The present invention can be used when outputting video and audio in a personal computer, an information processing terminal, or the like. Also, D
The present invention can also be used for outputting video and audio in a VD playback device or digital broadcast receiving device.

[0117]

As described above, the present invention provides a transmitting apparatus for transmitting digital video information with a blanking interval,
A receiving apparatus for receiving the digital video information, wherein the transmitting apparatus transmits digital audio information during the retrace period, and the receiving apparatus transmits the digital audio information during the retrace period. Receive information.

Thus, video information and audio information can be transmitted and received with high quality. Further, the present invention also provides a transmitting apparatus for generating frame information including digital video information with a blanking period, transmitting the encrypted frame information, and receiving and decoding the encrypted frame information, and decoding the decoded frame. Extracting the digital video information from the information, and a video display device to display, an encryption transmission system,
The transmitting device multiplexes digital audio information with the frame information in the flyback period, encrypts and transmits the multiplexed frame information of the digital audio information, and the video display device transmits the encrypted video information. Receiving and decoding frame information to generate frame information; extracting the digital audio information from the flyback period placed in the generated frame information; and converting the digital audio information into an audio signal.

As a result, it is possible to transmit and receive the video information and the audio information with high quality and protect the copyrighted work.

[Brief description of the drawings]

FIG. 1 shows a personal computer system 10
It is an external view which shows the external appearance.

FIG. 2 shows a personal computer system 10;
FIG. 3 is a block diagram showing the configuration of FIG.

FIG. 3 is a block diagram illustrating a configuration of a video connection unit 201 and a video connection unit 301.

FIG. 4 is a conceptual diagram showing a relationship between a vertical blanking period, a horizontal blanking period, and video information for one frame.

FIG. 5 shows changes in data enable signals DE, ADE, decoded video information, and encoded audio information corresponding to one frame over time.

FIG. 6 shows changes in data enable signals DE, ADE, decoded video information, and encoded audio information corresponding to one line over time.

FIG. 7 is a diagram showing a TMDS encoder 213 and a TMDS encoder;
It is a block diagram which shows the structure of the decoding part 311.

FIG. 8 is a flowchart showing an outline operation of the personal computer system 10 when reproducing coded video / audio information.

FIG. 9 is a flowchart illustrating an operation of device authentication.

FIG. 10 is a flowchart illustrating an operation of key sharing for each frame.

FIG. 11 is a flowchart showing operations of encrypting, transmitting, and decrypting audio information and video information in one line.

FIG. 12 is a diagram illustrating an HDCP encryption unit 215 [HDCP encryption unit 215;
21 is a transition chart showing a state transition of encryption [decryption] by the decryption unit 315].

[Explanation of symbols]

 Reference Signs List 10 personal computer system 20 PC main unit 30 CRT display device 41 keyboard 42 mouse 50a cable 50b cable 201 video connection unit 202 video / audio processing unit 203 DVD input / output unit 204 control unit 211 multiplex unit 212 encryption unit 213 TMDS encoding unit 214 authentication Key sharing unit 215 HDCP encryption unit 301 Video connection unit 302 Display control unit 303 CRT unit 304 Speaker control unit 305 Speaker 311 TMDS decryption unit 312 Encryption unit 313 Separation unit 314 Authentication key sharing unit 315 HDCP decryption unit

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04N 7/088 (72) Inventor Toshiro Nishio 1006 Odakadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd. (72 ) Inventor Hidekazu Suzuki 1006 Kadoma Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. F term (reference) 5C063 AB03 AC01 AC05 CA20 DA07 DA13 DB01 5J104 BA04 BA06 FA06

Claims (23)

[Claims] 1. A transmission system comprising: a transmitting device that transmits digital video information with a blanking interval, and a receiving device that receives the digital video information, wherein the transmitting device includes the blanking period. Wherein the receiving device receives the digital voice information during the flyback period. 2. A transmitting apparatus for generating, encrypting and transmitting frame information including digital video information with a blanking interval, receiving and decrypting the encrypted frame information,
A video display device for extracting and displaying the digital video information from the decrypted frame information, wherein the transmission device multiplexes digital audio information with the frame information during the flyback period. The digital audio information is transmitted after encrypting the multiplexed frame information, the video display device receives the encrypted frame information, generates the frame information by decoding, the generated frame An encryption transmission system for extracting the digital audio information from the flyback period placed in information and converting the digital audio information into an audio signal. 3. A transmitting apparatus for generating, encrypting and transmitting frame information including digital video information at one or more blanking periods, and multiplexing digital audio information with the frame information in the blanking period. A multiplexing unit for encrypting the digital audio information, an encryption unit for encrypting the frame information in which the digital audio information is multiplexed, and a transmission unit for transmitting the encrypted frame information. . 4. The generated frame information includes a vertical blanking period, and subsequently, for each line, includes a horizontal blanking period and includes line video information, and the digital audio information includes a plurality of lines. 4. The transmitting apparatus according to claim 3, wherein the multiplexing unit multiplexes the line voice information in the vertical blanking period and / or the horizontal blanking period. 5. 5. The image processing apparatus according to claim 1, wherein the encryption unit uses a frame key generation unit that generates a frame key used as an encryption key in accordance with the frame information, and uses the frame key generated in accordance with the frame information. 5. The transmitting apparatus according to claim 4, further comprising a frame encrypting unit for encrypting digital audio information and digital video information included in the frame information. 6. The frame encryption unit includes: a line encryption unit that encrypts line audio information and line video information included in the frame information using the frame key; and a key update unit that updates the frame key. Until the encryption of all the line audio information and line video information included in the frame information is completed, the next line audio information and the next line audio information are transmitted to the line encryption unit using the updated frame key. 6. A repetition control means for controlling to encrypt the line video information, and controlling the key updating means to update the updated frame key again. The transmitting device according to claim 1. 7. The encryption of the digital audio information and the digital video information,
The transmission device according to claim 5, wherein the same encryption method is used. 8. The line encryption means sets an initial value for audio, encrypts line audio information using the set initial value for audio, and then has the same value as the initial value for audio. The transmission apparatus according to claim 7, wherein an initial value for video is set, and line video information is encrypted using the set initial value for video. 9. The transmission device transmits the encrypted frame information to a video display device, wherein the encryption unit authenticates the video display device, generates the frame key, and transmits the frame information. In encryption,
The transmission device according to claim 5, wherein a common operation module is used. 10. The multiplexing means further generates a video enable signal indicating transmission of the digital video information in a period including the digital video information in the frame information, and generates the video enable signal in the blanking period. The transmitting device according to claim 4, wherein the transmitting device generates an audio enable signal indicating transmission of audio information, and the transmitting unit further transmits the generated video enable signal and the audio enable signal. 11. The multiplexing means generates an audio enable signal indicating transmission of the digital audio information in the vertical retrace period and / or the horizontal retrace period for multiplexing the digital audio information. The transmitting device according to claim 10, wherein 12. The multiplexing unit generates the frame information by using a multiplex control signal for identifying transmission of the digital audio information and the digital video information, and the transmitting unit transmits the multiplex control signal. The transmitting device according to claim 3, wherein 13. The transmitting apparatus according to claim 3, wherein the multiplexing unit generates frame information with a no-signal period between the digital audio information and the digital video information. 14. A video display device for receiving and decrypting the encrypted frame information from the transmission device according to claim 3, extracting the digital video information from the decrypted frame information, and displaying the digital video information. Receiving means for receiving the encrypted frame information; decoding means for decoding the encrypted frame information; and extracting digital audio information from the blanking period placed in the decoded frame information. A video display, comprising: extracting means for extracting digital video information from another period; and outputting means for displaying the extracted digital video information and converting the extracted digital audio information into an audio signal. apparatus. 15. The digital audio information includes a plurality of line audio information, and the frame information includes a vertical retrace period, and then sets a horizontal retrace period for each line. The video data includes video information, and the line audio information is multiplexed in the vertical retrace period and / or the horizontal retrace period. The video display device according to claim 14, wherein the line audio information is extracted. 16. The apparatus according to claim 16, wherein the decryption unit uses a frame key generation unit that generates a frame key used as a decryption key in accordance with the frame information; 16. The video display device according to claim 15, further comprising a frame decoding unit for decoding digital audio information and digital video information included in the encrypted frame information. 17. The frame decoding means, comprising: a line decoding means for decoding line audio information and line video information included in the encrypted frame information using the frame key; and a key for updating the frame key. Updating means, using the updated frame key to the line decrypting means until the decoding of all the line audio information and line video information included in the encrypted frame information is completed. A repetition control unit that controls to decode line audio information and the next line video information, and controls the key updating unit to update the updated frame key again. 17. The video display device according to claim 16, wherein 18. The decoding apparatus according to claim 18, wherein the frame decoding unit decodes the digital audio information and the digital video information.
17. The video display device according to claim 16, wherein the same decoding method is used. 19. The line decoding means sets an initial value for audio, decodes line audio information using the set initial value for audio, and then has the same value as the initial value for audio. 19. The video display device according to claim 18, wherein an initial value for video is set, and line video information is decoded using the set initial value for video. 20. The apparatus according to claim 16, wherein said decryption means uses a common arithmetic module in authentication by said video display device, generation of said frame key, and decryption of said encrypted frame information. Video display device. 21. The transmitting means further receives the video enable signal indicating transmission of the digital video information and the audio enable signal indicating transmission of the digital audio information, and the extracting means further includes: 16. The video display device according to claim 15, wherein the digital video information is extracted in a period indicated by the video enable signal, and the digital audio information is extracted in a period indicated by the audio enable signal. 22. The receiving means receives a multiplex control signal for identifying transmission of the digital audio information and the digital video information, and the extracting means uses the multiplex control signal to generate the digital audio information and the digital audio information. The video display device according to claim 14, wherein digital video information is extracted. 23. The receiving means receives the encrypted frame information with a no-signal period between the digital audio information and the digital video information, and the extracting means, In the no-signal period between the digital video information, the digital audio information and a multiplex control signal for identifying the reception of the digital video information is generated, using the generated multiplex control signal, the digital audio information and the The video display device according to claim 14, wherein digital video information is extracted.