JP2017108414A - Digital broadcast reception device and digital broadcast reception method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To grasp the number of devices receiving stream data even if a device relaying a stream is connected in stream data transmission over a copyright-protected bus.SOLUTION: A stream relaying device performs authentication for a relay between the stream relaying device and a relay source device when performing authentication between the stream relaying device and a relay destination device. The relay source device increments the number of devices that receive streams by the authentication. At completion of stream transmission between the relaying device and the relay destination device, the relaying device notifies the relay source device of the number of relay destination devices. The relay source device decrements the number of stream receiving devices on the basis of notification.SELECTED DRAWING: Figure 9

Description

  The present invention relates to a recording / reproducing apparatus, a receiving apparatus, and an input / output apparatus that simultaneously receive and transmit stream data such as a digital video / audio signal via a digital interface.

  With the development of digital video signal processing technology and recording / playback technology, set-top boxes (STB) that receive satellite broadcasts and CATV, digital broadcast receivers such as digital TVs, digital VTRs, disk recorders, etc. are devices for general households. It has become possible to realize. When video / audio signals are exchanged between these digital AV devices, it is desirable to transmit them as stream data in the form of digital signals in order to prevent deterioration of signal quality. As a digital interface most suitable for transmission of such stream data, there is a high-speed serial bus (hereinafter referred to as 1394 bus) defined in the IEEE 1394-1995 standard. With the 1394 bus, a maximum of 63 devices can be freely connected in a tree-like connection, with a maximum transfer rate of 400 Mbps and an isochronous transfer system suitable for data transmission that needs to be transmitted in real time such as video and audio streams, etc. The requirements suitable for the connection of the AV apparatus are satisfied.

  On the other hand, recording and playback devices such as digital VTRs perform signal recording and playback digitally, so there is essentially no change in signal quality due to repeated recording and playback, and the same copy as the original can be generated easily and many times. Is possible. This may lead to the possibility that a large number of copies of video / audio data (contents) whose copyrights are reserved will be copied in large quantities beyond the range of use in ordinary households.

  As a technique for preventing such illegal copying of content, a DTCP (Digital Transmission Contents Protection) system is adopted in the 1394 bus. In the DTCP method, an AV apparatus that handles a copyrighted video / audio stream, that is, an apparatus that successfully authenticates each other, such as a broadcast receiver, a recording / reproducing apparatus, and a display apparatus. Stream reception that sends a scrambled stream from a stream sending device (hereinafter referred to as a source device) so that data can be transmitted only between them, and obtains key data for descrambling beforehand by authentication The side apparatus (hereinafter referred to as a sink apparatus) receives and restores the stream, and reproduces or records it.

The video / audio stream is provided with copy control information that describes conditions relating to data copying, and as a result, “copy free” (copy unlimited), “copy never” (copy prohibited), “copy one generation” (copy 1 generation) It is classified into one of three types.
A recordable device such as a digital VTR can receive and record only a “copy free” or “copy one generation” stream. When a “copy one generation” stream is recorded, the copy control information is set to “ Change to “no more copies”. In an apparatus for reproducing and displaying video and audio such as a digital TV, a stream can be received and reproduced regardless of copy control information.
An example of such a technique is described in JP-A-11-205310.

JP-A-11-205310

  As described above, in the DTCP method, when a copy-restricted content (for example, “copy one generation” content) is copied, authentication is always performed between the source device and the sink device. Therefore, the source device can grasp how many sink devices have been authenticated at that time. However, when considering a device that simultaneously inputs / outputs content, for example, a device that outputs the content while recording the input content, the original source device is the sink that is actually receiving the content. The number of devices cannot be grasped. In other words, in the DTCP system, it is impossible to grasp and limit the number of sink devices that receive copy-restricted content. This means that the copy generation can be limited, but the total number of copies cannot be limited.

And, as a device that inputs and outputs content simultaneously, input and output are not necessarily performed by the same type of interface, but input may be performed by a 1394 bus and output may be performed by wireless transmission.
An object of the present invention is to enable a device (source device) that transmits content subject to copy restrictions to correctly grasp the number of sink devices that receive the content in an environment where a plurality of devices are connected. .

In order to achieve the above object, in the present invention, a device that inputs and outputs content not only authenticates with the original source device as input when inputting content that is subject to copy restriction and outputting the content, Further, authentication is performed with the original source device by the number of authentications with the device that receives the output. Whether or not to authenticate with the original source device as an input amount is only when the input is actually met and the authentication requirement is met.
By doing so, the original source device can grasp the number of sink devices that receive the content output by itself.
In addition, in order to distinguish from a case where a sink device that performs only input performs authentication related to the same content multiple times, information for identifying the fact is added when performing authentication for grasping the number of sink devices. To.
In this way, even when authentication for the same content is performed a plurality of times, it is possible to avoid adding the number of times as the number of sink devices.

  According to the present invention, in an environment where a plurality of devices are connected, a device (source device) that transmits content subject to copy restrictions can correctly grasp the number of sink devices that receive the content.

1 is a block diagram showing a configuration of an AV system including a stream data input / output device according to an embodiment of the present invention. It is a block diagram which shows the detailed structure of the interface means of the stream input / output apparatus by one Example of this invention. It is a figure which shows the data transmission method between a digital satellite broadcast receiver and digital TV. It is a figure which shows the data transmission method between a hard disk recorder, a digital satellite broadcast receiver, and digital TV. It is a figure which shows the data transmission method between a hard disk recorder, a digital satellite broadcast receiver, and digital TV. It is a figure which shows the data transmission method between digital VTR, a digital satellite broadcast receiver, and digital TV. It is a sequence diagram which shows the data transmission procedure between a stream data recording / reproducing apparatus and a digital satellite broadcast receiver. It is a figure which shows the transmission packet format of stream data. It is a sequence diagram which shows the data transmission procedure between the stream data input / output apparatus by one Example of this invention, and another apparatus. It is a sequence diagram which shows the data transmission procedure between the stream data input / output apparatus by one Example of this invention, and another apparatus. It is a block diagram which shows the structure of the stream data input / output apparatus by one Example of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows the configuration of an AV system configured by using a hard disk recorder which is an embodiment of a stream data input / output device according to an embodiment of the present invention, and includes a digital satellite broadcast receiver 3, a digital TV 4, Assume that the hard disk recorder 1 and the digital video tape recorder 2 are connected to each other by a 1394 bus.

  The digital satellite broadcast receiver 3 demodulates the signal received by the antenna 31 at the front end 32, selects desired program data from the transport stream multiplexed by the demultiplexer 33, and connects the interface unit 35 via the terminal 36. Output as a stream on the bus. The CPU 34 controls each part of the digital satellite broadcast receiver 3 by executing a program stored in a built-in memory or a memory (not shown). Further, the CPU 34 reads program guide information (EPG) from the received transport stream, generates screen data for operation including screen data for presenting the program guide information to the user, and transmits the screen data to the 1394 bus, or transmits it to the 1394 bus. Processing such as transmission / reception of control commands is performed.

  The digital TV 4 receives the stream sent on the 1394 bus by the interface unit 42 via the terminal 44a or 44b, restores it to video and audio data by the decoder 43, and the video data passes through the signal processing circuit 45 to the CRT 46. indicate. The audio data is reproduced from a speaker (not shown) through an audio signal processing circuit (not shown). The CPU 41 controls each part of the digital TV 4 by executing a program stored in a built-in memory or a memory (not shown). Further, the CPU 41 receives screen data for controlling other devices connected by the 1394 bus and draws and displays the screen data in a memory included in the signal processing circuit 45, or commands for controlling other devices. Send and receive. In particular, according to the present invention, the stream sent on the 1394 bus is received by the interface unit 42 via the terminal 44a, and on the other hand, on the CRT 46 via the decoder 43 and the signal processing circuit 45 as described above. On the other hand, the received stream is output again from the terminal 44b onto the 1394 bus.

  The disk recorder 1 receives the stream sent on the 1394 bus by the interface unit 14 via the terminal 15 a, converts it into a data format for writing to the disk 11 by the signal processing circuit 13, and records it on the disk 11. Further, the signal read from the disk 11 is converted into a stream format for transfer by the signal processing circuit 13, and is transmitted as a stream from the interface unit 14 to the 1394 bus via the terminals 15a and 15b. The CPU 12 controls each part of the disk recorder 1 by executing a program stored in a built-in memory or a memory (not shown). Further, the CPU 12 creates screen data indicating the operation content of the disk device 1 and transmits it to the 1394 bus, and performs processing such as transmission and reception of control commands via the 1394 bus. In particular, according to the present invention, the stream sent on the 1394 bus is received by the interface unit 14 via the terminal 15a, and on the other hand, as described above, the stream is recorded on the disk 11 via the signal processing circuit 13. On the other hand, the received stream is output again from the terminal 15b onto the 1394 bus.

  The digital VTR 2 receives the stream sent on the 1394 bus by the interface unit 22 via the terminal 26, converts it into a recording format to a tape medium by the signal processing circuit 23, and converts it from a head 24 attached to a rotating drum (not shown). Recorded on the tape 25. Conversely, the data read from the tape 25 by the head 24 is converted into a transfer stream format by the signal processing circuit 23 and sent out from the interface unit 22 to the 1394 bus via the terminal 26. The CPU 21 executes a program stored in a built-in memory or a memory (not shown) to control each part of the digital VTR 2, creates screen data indicating the operation contents of the digital VTR 2, and transmits the screen data to the 1394 bus. Processing such as transmission / reception of control commands via the bus is performed.

  FIG. 2 shows a more detailed configuration of the interface units 14, 22, 35, 42 realized by a configuration common to each device. The physical layer processing unit (PHY) 54 and the link layer processing unit (LINK) 53 leading to the 1394 bus connector respectively execute physical layer and link layer processing defined by the IEEE 1394 standard. An isochronous transfer FIFO 52 for storing data transferred on the 1394 bus in the isochronous transfer mode and an asynchronous transfer FIFO 55 for storing data transferred on the 1394 bus in the asynchronous transfer mode are connected to the input / output of the isochronous transfer FIFO. Is scrambled or descrambled as required by the data encryption / decryption unit 51 and connected to a signal processing unit in the apparatus. The input / output of the isochronous transfer FIFO 55 is connected to the CPU in the apparatus via the host interface 56. The CPU transmits and receives control commands transmitted and received on the 1394 bus using the asynchronous transfer mode, and controls each part of the interface unit via the host interface 56.

  Next, the operation of the AV system shown in FIG. 1 will be described. First, when a program broadcast by digital satellite broadcast is received by the digital satellite broadcast receiver 3 and viewed by the digital TV 4, a desired program is selected by the digital satellite broadcast receiver 3 and is streamed on the 1394 interface. Is received by the digital TV 4 and reproduced and displayed. The 1394 bus defines two modes, isochronous transfer and asynchronous transfer. When a broadcast program stream is transferred in real time, the normal isochronous transfer mode is used. A stream data transmission format and stream transmission / reception control may be performed using a method defined in the IEC61883 standard.

  FIG. 3 shows a logical connection form when stream data is transmitted from a digital satellite broadcast receiver to a digital TV in accordance with a stream data transmission control system defined in the IEC61883 standard. In the IEC61883 standard, a virtual stream data input / output unit called a “plug” is provided, and a “connection” that is a logical connection is set between plugs, thereby defining a stream data transmission device and a reception device. In the example of FIG. 3, the output plug 301 of the digital satellite broadcast receiver 3 and the input plug 401 of the digital TV 4 are connected using an isochronous data channel X on the 1394 bus, and stream data is transmitted using this channel X. Is shown. Stream data transmission / reception control is executed by writing to a plug control register provided in the bus address space of each device connected to the 1394 bus. For example, the output plug of the digital satellite broadcast receiving device 3 from the digital TV 4 is executed. The transmission channel X is written in the register as a set value, and the digital TV sets its own input plug register to receive the channel X, so that the connection is established, and the satellite broadcast receiver 3 uses the channel X to stream to the digital TV 4 Will be able to send.

  As described above, the connection can be established from the digital TV 4 side, that is, the sink side, as well as from the satellite broadcast receiver, that is, the source side. Further, a command for instructing connection establishment from the source side to the sink side can be provided. It is also possible to establish a connection by sending it. When the transmission of the stream data is terminated, the established connection is discarded by writing data so as to release the connection using the channel X in the input plug register and the output plug register of each device. The IEC61883 standard defines a point-to-point connection that connects between an input plug and an output plug, and a broadcast connection that connects between an input plug or an output plug and an isochronous data channel. Unless otherwise indicated, point-to-point connections are simply expressed as connections.

  Next, the operation when a satellite broadcast program is recorded by the disk recorder 1 will be described. In this case, as shown in FIG. 4, a connection is established between the output plug 301 of the satellite broadcast receiver 3 and the input plug 101 of the disk recorder 1 to transmit a program stream, and the disk recorder 1 records it on the disk. To do. At this time, by receiving a stream of the same channel X by the digital TV 4, it is possible to perform a so-called recording monitor in which the video of the stream recorded by the disk recorder is decoded and displayed. In IEC61883, a connection can be added to a connection established in advance so that a stream of the same channel can be used for other devices, and adding a connection later is called "overlay". .

  As shown in FIG. 4, a connection is established between the output plug of the digital satellite broadcast receiver 3 and the input plug 401 of the digital TV 4. In this case, it is possible to overlay the connection to the input plug 101 of the disk recorder 1 on the connection established for transmitting the stream from the digital satellite broadcast receiver 3 to the digital TV 4 for viewing. Alternatively, an input connection to the digital TV 4 can be overlaid on a connection from the digital satellite broadcast receiver 3 to the disk recorder 1. When establishing a connection, as in the case of viewing, the connection may be made from any of the satellite broadcast receiver 3, the digital TV 4, and the disk recorder 1, or a command is sent from the other device. It may be executed.

  Various operations can be considered for the user's operation when performing the recording operation, and a command input by operating the remote controller or the like while viewing the GUI screen displayed on the digital TV 4 is digitally transmitted from the TV as a command via the 1394 bus. It may be sent to the satellite broadcast receiver 3 and the disk recorder 1, or the GUI screen generated by the digital satellite broadcast receiver 3 or the disk recorder 1 is sent to the digital TV 4 for display, and the digital satellite broadcast receiver 3 or It can also be realized by a method of performing recording by operating the remote controller or the panel on the disk recorder 4 side.

  A command for operating the digital satellite broadcast receiver 3 or the disk recorder 1 from the digital TV 4 or establishing a connection with the counterpart device is a command for controlling the AV device according to the command transfer protocol defined in the IEC61883 standard. As a specification, an AV / C command set determined by 1394 Trade Association may be used. In addition, as a method for transmitting the GUI screen to other devices, a method defined in the EIA775A standard, a method using the panel subunit indicated by the AV / C command set specification described above, and a network control specification of the AV device can be used. A GUI implementation method defined in the HAVi (Home Audio Video interoperability) specification defined can be used.

Next, a case where a broadcast program recorded on the disk recorder 1 is reproduced and displayed on the digital TV 4 will be described. FIG. 5 shows the transmission state of the stream when the stream is transmitted from the disk recorder 1 and displayed on the digital TV 4. In this case, a connection is set from the output plug 102 of the disc recorder 1 to the input plug 401 of the digital TV 4, and the stream received by the digital TV 4 is decoded and displayed so that the stream is transmitted. As in the case of viewing and recording, various forms are conceivable for the device for establishing a connection and the operation method of the user.
When recording or reproducing a stream with the digital VTR 2, as shown in FIG. 6, the input plug 201 or the output plug 202 of the digital VTR 2 and the output plug 301 or the digital TV 4 of the digital satellite broadcast receiver 3 as in the case of the disk recorder. A stream may be transmitted by establishing a connection with each of the input plugs 401.

  In the above description, the case where copy restriction is applied to a program received from satellite broadcasting has been described without considering. A program received from a satellite broadcast or the like and recorded on a disk recorder is transmitted as a stream on the bus, and can be copied if received by another disk recorder or digital VTR. In the IEEE 1394 and IEC61883 standards, there are no particular restrictions on devices that can send and receive streams. By overlaying connections as described above, any other device can be used to stream the stream flowing on the bus. However, it was basically possible to receive and use it, and it was also possible to record a single stream on a plurality of devices at the same time to make many copies.

Therefore, in the case of transmitting contents such as movies on the 1394 bus, where copyrights are reserved among broadcast programs, etc., and it is necessary to limit the production of copies in order to protect the rights of copyright holders. In order to prevent such content from being copied indefinitely, a DTCP (Digital Transmission Content Protection) method that defines copyright protection specifications on the 1394 bus is used.
According to the DTCP method, when content whose copyright is reserved and the copy is restricted is to be transmitted as a stream on the 1394 bus, each other's devices are mutually authenticated using authentication information incorporated in the device in advance. Only when the authentication is successful, the key data for scrambled and transmitted content is shared with each other, the encrypted content stream is transmitted from the source device side to the 1394 bus, and the sync is transmitted. By restoring the stream received on the side using a shared key, it is possible to transmit and receive content only between devices having authentication information.

  FIG. 7 shows a transmission procedure when content with copy restrictions is transmitted from the digital satellite broadcast receiver 3 to the disk recorder 1 in the AV system shown in FIG. In FIG. 7, when a stream is to be transmitted from the satellite broadcast receiver 3 to the disk recorder 1, first, as described above, a connection is established between the output plug of the satellite broadcast receiver 3 and the input plug of the disk recorder 1. (Procedure 1001), the key data for encrypting the content is generated by the satellite broadcast receiver 3 on the source side (procedure 1002), and the stream scrambled by this key data is put on the bus. Transmission is started (procedure 1003). When the disc recorder 1 on the sink side receives the scrambled stream, the disk recorder 1 requests authentication on the source side (step 1004), and the other party authenticates each other and exchanges key data. (Procedure 1005). If the authentication is successful, it becomes possible to calculate the content encryption key data on the sink side, calculate this value (step 1006), and decrypt and receive the stream sent from the source side (step 1006). Procedure 1007).

When the transmission of the stream is finished, the stream from the source side is stopped (procedure 1008), the connection between the source and the sink is discarded (procedure 1009), and the key data on the source side sink side is discarded (procedures 1010 and 1011). ).
Content copy restrictions are identified using copy control information having four levels of “copy free”, “copy never”, “copy one generation”, and “no more copies”. FIG. 8 shows the data packet format of the isochronous transfer mode used for transmitting the stream data on the 1394 bus. The packet is composed of 32-bit header information, a header CRC, a data field, and a data CRC. The header information includes a 16-bit Data Length field indicating the packet length, a Tag field used to identify the data format of the packet, a Channel field indicating the isochronous channel number used to transmit the packet, and the type of packet transaction. It has a Tcode field and a Sy field used for data synchronization. By assigning the values representing the above four levels using the upper 2 bits of the Sy field, the copy control information of the content transmitted by the stream is identified.

  The content of “copy free” is not limited in copying, can be freely transmitted / received by any device, and does not need to be scrambled when transmitting / receiving to / from the bus. The contents of the other three levels “copy never”, “copy one generation”, and “no more copies” are limited in copying and need to be scrambled for transmission on the bus. The content of “copy never” cannot be received and stored in a medium by a recording device such as a disk recorder or a VTR. For example, the recording operation is performed when the satellite broadcast receiver transmits to a digital TV for viewing. Only when not performed can the transmitted stream be received. The content of “copy one generation” can be recorded on the recording device, but when it is once recorded and then played back and transmitted from the recording device, the copy control information is changed to “no more copies”. There must be. The content of “no more copies” is only allowed to display the generated data in the same way as “copy never”.

In a device having information for authentication, the content processing according to the copy control information described above is always performed correctly, thereby preventing unauthorized copying of copy-restricted content in the DTCP method.
Next, the digital TV 4, which is an embodiment of the present invention, receives the stream sent on the 1394 bus by the interface unit 42 via the terminal 44a. On the other hand, as described above, the decoder 43, the signal processing circuit The operation in the case of displaying on the CRT 46 via 45 and outputting the received stream from the terminal 44b to the 1394 bus again will be described. In this example, the digital TV 4 receives a stream subject to copy restriction from the digital satellite broadcast receiver 3 via the 1394 bus and outputs it to the hard disk recorder 1. FIG. 9 shows the procedure.

  In FIG. 9, when receiving a stream subject to copy restriction from the digital satellite broadcast receiver 3, first, as described above, a connection is first established between the output plug of the satellite broadcast receiver 3 and the input plug of the digital TV 4. Established (procedure 1101), generates key data for encrypting content by the satellite broadcast receiver 3 on the source side (procedure 1102), and transmits the stream scrambled by this key data on the bus Start (procedure 1103). When the digital TV 4 on the sink side receives the scrambled stream, the digital TV 4 requests authentication on the source side (step 1104), authenticates the other party between the source and sink, and exchanges key data ( Procedure 1106). If the authentication is successful, it becomes possible to calculate the content encryption key data on the sink side, calculate this value (step 1107), and decrypt and receive the stream sent from the source side (step 1107). Procedure 1108). When the authentication is successful by the processing of 1104 and 1106, the source device, that is, the digital satellite broadcast receiver 3 in this case, increments the number of sink devices receiving the stream output by itself by one (procedure) 1105). However, this does not apply to the case of a sink device for which valid authentication processing has already been confirmed.

  Now, in this case, the hard disk recorder 1 receives the above-mentioned stream (originally output by the digital satellite broadcast receiver 3) from the digital TV 4. First, the output plug of the digital TV 4 and the input plug of the hard disk recorder 1 are connected. A connection is established between them (procedure 1201), and key data for encrypting content is generated by the digital TV 4 on the source side (procedure 1202). Transmission is started (procedure 1203). When the hard disk recorder 1 on the (second) sink side receives the scrambled stream, it requests authentication on the source side (digital TV 4) (step 1204). At this time, the digital TV 4 according to the present invention temporarily rejects the authentication request from the hard disk recorder 1 (procedure 1205). During this time, the digital TV 4 requests authentication to the digital satellite broadcast receiver 3 which is the (original) source device (step 1206), and authenticates the other party between the source and the sink, and the key data can be exchanged. Performed (procedure 1208). When making an authentication request in this procedure 1206, even if it is a sink device for which valid authentication processing has already been confirmed, a request is made with information indicating that the number of sink devices needs to be incremented. . Upon receiving this, the source side (digital satellite broadcast receiver 3) increments the number of sink devices receiving the stream output by itself by one (step 1207). If the authentication with the original source device is successful, the digital TV 4 requests the hard disk recorder 1 for authentication again (step 1209), and the other side authenticates the other party and exchanges key data. (Procedure 1211). If the authentication is successful, the (second) sink side can calculate key data for content encryption, calculate this value (procedure 1212), and decrypt and receive the stream sent from the source side. (Procedure 1213). When the authentication is successful by the processing of 1209 and 1211, the source device, that is, the digital TV 4 in this case, increments the number of sink devices receiving the stream output by itself by 1 (procedure 1210).

In the above example, if it is assumed that stream input / output is not performed with devices other than the digital satellite broadcast receiver 3, the digital TV 4, and the hard disk recorder 1, the digital satellite broadcast receiver 3 at the time of step 1213. The number of authenticated sink devices managed by the digital TV 4 is 2, while the number of authenticated sink devices managed by the digital TV 4 is 1.
In FIG. 9, the case of incrementing the number of sink devices has been described, but the case of decrementing in reverse will be described with reference to FIG. In this example, a case where the hard disk recorder 1 which is the (second) sink device stops receiving the stream will be described.

  In FIG. 10, the procedure 1301 is the beginning. First, the hard disk recorder 1 that has received the stream discards the connection established for stream transmission / reception. Thereafter, the key data on the source side and the sink side are discarded (procedures 1302 and 1303). The digital TV 4 that has discarded the connection with the sink side (hard disk recorder 1) decrements the number of sink devices managed by itself by the number of sinks in the connection (procedure 1304). Further, the digital satellite broadcast receiver 3 which is the original source device is notified that the number of sink devices has decreased (step 1305). Information of the reduced number of sink devices is added to this notification. Receiving the notification, the digital satellite broadcast receiver 3 decrements the number of sink devices managed by itself by the reduced number of sink devices (step 1306).

In the above example, if it is assumed that stream input / output is not performed with devices other than the digital satellite broadcast receiver 3, the digital TV 4, and the hard disk recorder 1, the digital satellite broadcast receiver 3 at the time of step 1306. The number of authenticated sink devices managed by the digital TV 4 is 1, while the number of authenticated sink devices managed by the digital TV 4 is 0.
If the explanation of the procedure 1304 is supplemented, if the digital TV 4 discards the connection with the digital satellite broadcast receiver 3 in the state after the procedure 1210 in FIG. 9, the digital satellite broadcast receiver 3 The number of sink devices managed by itself is decremented by the number of sinks in the connection, that is, two. As a result, the number of sink devices becomes zero.

As described above, content that is subject to copy restrictions is transmitted even in an environment where a device that inputs and outputs content at the same time, for example, a device that outputs the content while reproducing the input content is connected. A device (source device) that can correctly understand the number of sink devices that receive the content. Then, by knowing the number, for example, it becomes possible to limit the number of copies.
In the above description, the digital TV 4 that uses the 1394 bus for both input and output has been described as an example of content input / output simultaneously. However, in the present invention, it is not always necessary to use the same transmission method for input and output. As in the hard disk recorder 1r shown in FIG. 11, the input is a 1394 bus and the output is performed by wireless transmission. It is also applicable to a device.
Furthermore, in the above, as an example of a device that inputs and outputs content simultaneously, as in the case of a digital TV 4 or a hard disk recorder 1, the case where the input stream is directly used by reproduction or recording is taken as an example. explained. However, the present invention can be applied even to an apparatus that simply relays a stream, such as the above-described input is a 1394 bus and the output is wireless transmission.

1, 1r ... disk recorder 2, 2r ... digital VTR
3 ... Satellite broadcast receiver 4 ... Digital TV
11: Hard disk 12, 21, 34, 41 ... CPU
13, 23, 45 ... signal processing circuits 14, 22, 35, 42, 14r, 22r ... interface means 15a, 15b, 26, 36, 44a, 44b, 15r, 26r ... terminal 24 ... head 25 ... tape 31 ... antenna 32 ... front end 33 ... demultiplexer 43 ... decoder 46 ... CRT
51. Encryption / decryption means

In order to solve the above problem, the technical idea disclosed in the claims may be used .

Claims (7)

Interface means for transmitting and receiving stream data and control data;
In an input / output device comprising: decryption means for descrambling stream data received by the interface means; and encryption means for scrambling stream data transmitted by the interface means.
The input / output device performs a first authentication process with a first other device that transmits stream data received via the interface unit, thereby performing a descrambling process in the decryption unit. Exchange key information for
In accordance with copy control information added to the stream data received by the interface means, the stream data obtained by controlling the descrambling process by the decrypting means, and controlling the scramble process by the encrypting means, the interface means When sending to a second other device via
The third authentication process is performed with the first other device before the second authentication process is performed with the second other device, and the third authentication process is successful. And performing the second authentication processing. The input / output device according to claim 1.
An input / output device characterized in that, when transmission of stream data to be transmitted via the interface means is completed, the first other device is notified via the interface means of stopping. The input / output device according to claim 1 or 2,
A built-in or removable recording medium for recording data received via the interface means,
The data obtained by controlling the descrambling process by the decoding means according to the copy control information added to the stream data received by the interface means and the information based on the copy control information are recorded on the recording medium. I / O device. The input / output device according to any one of claims 1 to 3,
Display means for displaying data received via the interface means,
The data obtained by controlling the descrambling process by the decoding means according to the copy control information added to the stream data received by the interface means and information based on the copy control information are displayed on the display means. I / O device. Interface means for transmitting and receiving stream data and control data;
Decoding means for descrambling the stream data received by the interface means;
In an input / output device having encryption means for scrambling stream data transmitted by the interface means,
The input / output device sets a first channel for transmitting stream data with a first other device that transmits stream data received via the interface means,
By exchanging key information for descrambling in the decryption means by performing a first authentication process with the first other device,
The stream data obtained by controlling the descrambling process by the decrypting means according to the copy control information added to the stream data received by the interface means on the first channel is scrambled by the encrypting means. When controlling and transmitting to the second other device via the interface means,
Set up a second channel for transmitting stream data to and from the second other device,
Before performing a second authentication process with the second device, a third authentication process is performed with the first other device, and a second authentication process is performed with the first other device. An input / output device characterized in that a third authentication process is performed and the second authentication process is performed when the third authentication process is successful. The input / output device according to claim 5,
When the setting of the second channel is canceled, the input / output device notifies the first other device of the cancellation via the interface means. First interface means for receiving stream data and control data;
Second interface means for transmitting stream data and control data;
Decoding means for descrambling the stream data received by the first interface means;
In the input / output device having the encryption means for scrambling the stream data transmitted by the second interface means,
Exchange of key information for descrambling processing in the decryption means by performing authentication processing with the first other device that transmits the stream data received via the first interface means And
In accordance with copy control information added to the stream data received by the first interface means, the stream data obtained by controlling the descrambling process by the decrypting means is controlled by the scramble process by the encrypting means. , When transmitting to the second other device via the second interface means,
An input / output device comprising: performing authentication processing with the first other device before performing authentication processing with the second other device.

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