JP4112342B2 - Tuner module, receiving system, and encryption processing method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a tuner module having a copyright protection function.
[0002]
[Prior art]
IEEE 1394, which is a bus standard for transmitting digital broadcast signals between devices, defines a DTCP (5C Digital Transmission Content Protection) specification that encrypts and protects transmitted signals (see Non-Patent Document 1).
[0003]
According to the published document, it is explained that in transmitting a digital broadcast signal, after mutual authentication between devices, the copyright can be protected by encrypting the transmitted signal.
[0004]
[Non-Patent Document 1]
[Search October 30, 2002], Internet <URL: http://www.dtcp.com/data/wp_spec.pdf>
[0005]
[Problems to be solved by the invention]
However, in the encryption method described in the above DTCP specification, when encrypting a digital broadcast signal, in order to encrypt all contents and control signals included in the digital broadcast signal, each device has encryption processing and There is a problem that extra hardware resources for decoding and software resources for controlling them are required.
[0006]
The present invention has been made to solve the above problems, and an object of the present invention is to provide a tuner module that receives a digital broadcast and efficiently encrypts the digital broadcast signal.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a demodulator that demodulates a signal from an antenna that receives a digital broadcast, a descrambler that descrambles the signal demodulated by the demodulator, and an authentication that authenticates the receiver. After mutually authenticating with the receiver by the processing means and the authentication processing means, the signal to be cryptographically protected encrypts the signal from the descrambler, and signals other than the signal to be cryptographically protected are signals from the descrambler And a cryptographic processing means for transmitting to the receiver as it is, a tuner module is provided.
[0008]
At this time, it is preferable that the encryption processing means transmits a signal that does not need to be copyright-protected as it is to the receiver.
In addition, the non-signaling is preferably performed by null packetization or zero padding processing.
The tuner module is preferably connectable to the display device using a PC card, a compact flash (registered trademark), a USB, or a PCI bus.
[0009]
In this way, when a tuner module including a front-end processing unit such as a tuner is connected to a general-purpose device such as a PC (Personal Computer) or PDA (Personal Digital Assistance), the hardware of the general-purpose device is used. Wear resources and software resources can be constrained.
[0010]
Further, the present invention provides a demodulating means for demodulating a signal from an antenna for receiving a digital broadcast, a descrambler for descrambling the signal demodulated by the demodulating means, an encryption processing means for encrypting a signal from the descrambler, A tuner module having authentication processing means for authenticating a receiver is connected to a receiver having decoding processing means for decoding an encrypted signal, MPEG decoding processing means, and authentication processing means for authenticating a device. When the tuner module is used as a digital broadcast receiver, the tuner module mutually authenticates with the receiver by the authentication processing means, then encrypts a signal to be cryptographically protected, and other than the signal to be cryptographically protected, An encryption processing method is provided that transmits to the receiver .
[0012]
At this time, it is preferable that the encryption processing means transmits a signal that does not need to be copyright-protected as it is to the receiver.
In addition, the non-signaling is preferably performed by null packetization or zero padding processing.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, this invention is not limited to the following embodiment.
FIG. 1 is a block diagram of a digital broadcast receiving apparatus when a tuner module according to an embodiment of the present invention is connected to a general-purpose device such as a PC (Personal Computer) or a PDA (Personal Digital Assistance).
[0014]
As shown in FIG. 1, a tuner module 1 of the present invention includes an input unit 15 from an antenna, a demodulating unit 2 for demodulating a digital broadcast signal input from the input unit 15 from the antenna, and the demodulating unit. 2, a descrambler 3 that descrambles the signal demodulated by 2, and encryption processing means 4 that encrypts the signal descrambled by the descrambler 3. Also, authentication processing means 5 for performing mutual authentication processing with other devices, encryption key storage (or generation generated by a predetermined method) for mutual authentication processing, EMM, ECM signal And filtering 7 for processing. Although detailed explanation is omitted, the demodulation means 2 also performs channel selection, error correction, and the like.
[0015]
The receiver 8 also includes a decryption processing means 9 for decrypting the encrypted signal, an MPEG decode 10, a copyright protection processing means 11, an authentication processing means 12 for performing mutual authentication processing, and a mutual authentication. A processing encryption key storage (or generation generated by a predetermined method) 13 and a viewability determination unit 14 are provided.
[0016]
The tuner module 1 can be used by being inserted into a compact flash (registered trademark) slot of a PC or PDA, for example. The tuner module 1 can be connected to the receiver 8 realized by a PC, PDA, or the like by a general-purpose I / F such as a PC card I / F, USB, or PCI bus. In this case, the I / F It is necessary to protect copyright from the need to prevent unauthorized copying of content.
[0017]
In the following description, it is assumed that the receiver 8 is a PDA and the general-purpose I / F is a PC card bus.
As shown in FIG. 1, when the tuner module 1 and the PDA 8 are connected, when the power is turned on or when the tuner module 1 and the PDA 8 are connected, the PDA 8 and the tuner module 1 perform mutual authentication.
[0018]
The mutual authentication is performed using, for example, a mutual authentication key shared between the PDA 8 and the tuner module 1 in advance. For example, a common key cryptosystem is used and processing is performed in the following procedure.
[0019]
First, a random number is transmitted from the authentication processing means 12 of the PDA 8 to the authentication processing means 5 of the tuner module 1. The tuner module 1 encrypts the random number using the encryption key for mutual authentication processing from the encryption key storage means 6 for mutual authentication processing. Then, the encrypted random number is transmitted to the authentication processing means 12 of the PDA 8 via the authentication processing means 5.
[0020]
Next, the PDA 8 compares the encrypted random number sent from the tuner module 1 with the encrypted random number obtained by encrypting the random number by the PDA 8 itself. As a result, if both data match, it is confirmed from the PDA 8 that the tuner module 1 possesses a predetermined mutual authentication key.
[0021]
In the above procedure, the case where a random number is first transmitted from the PDA 8 to the tuner module 1 has been described. Conversely, a case where a random number is transmitted from the tuner module 1 to the PDA 8 will be described.
[0022]
First, a random number is transmitted from the authentication processing means 5 of the tuner module 1 to the authentication processing means 12 of the PDA 8. The PDA 8 encrypts the random number using the encryption key for mutual authentication processing obtained from the encryption storage means 13 for mutual authentication processing. The encrypted random number is transmitted to the authentication processing means 6 of the tuner module 1 via the authentication processing means 12.
[0023]
Next, the tuner module 1 compares the encrypted random number sent from the PDA 8 with the encrypted random number encrypted by the tuner module 1 itself. As a result, when the two data match, it is confirmed that the PDA 8 from the tuner module 1 possesses a predetermined mutual authentication key.
[0024]
In this way, the mutual authentication process between the tuner module 1 and the PDA 8 is completed. Since the data generated mutually at this time is a random number, for example, it is difficult to store the data at the time of the previous authentication and divert it to this time, and security is maintained.
[0025]
Here, it is assumed that the encryption key for mutual authentication processing is secretly shared in advance by the tuner module 1 and the PDA.
In addition, the mutual authentication method is not limited to the method described here, and for example, a public key encryption method may be used.
Next, after the mutual authentication is completed, the PDA 8 and the tuner module 1 share a session key used in the subsequent encryption processing. The session key here is a key that is generated so as to be different every time mutual authentication processing is performed, for example, a key that is generated using a random number.
[0026]
That is, the security of copyright protection is improved by making it impossible to encrypt or decrypt the current broadcast content using the previous session key. At this time, the session key may be generated by the PDA 8, the tuner module 1 or the data generated by the PDA 8 and the tuner module 1 may be combined.
[0027]
In addition, after the session key is shared between the PDA 8 and the tuner module 1, a signal transmitted between the PDA 8 and the tuner module 1 is cryptographically protected using the session key.
[0028]
When the above processing is performed by the PDA 8, it is assumed that software processing is performed in the PDA 8.
The encryption process may be performed by preparing a coprocessor different from the main CPU in the PDA 8.
Next, a method for classifying signals transmitted from the tuner module 1 to the PDA 8 will be described. Here, (1) a signal to be cryptographically protected, (2) a signal that does not need to be cryptographically protected, and (3) an unnecessary signal will be described.
[0029]
The digital broadcast signal received by the tuner 15 such as the antenna input is demodulated and encrypted by the tuner module 1 and then transmitted to the PDA 8. The form of the broadcast signal is a transport stream (hereinafter TS) format. TS is a standard defined by the MPEG system and will not be described in detail, but is a standard for multiplexing and transmitting broadcast content (video, audio data, or data for data broadcasting) and additional information for receiving the broadcast content. Yes, it is possible to include a plurality of broadcast contents in one TS.
[0030]
Further, the additional information for receiving a plurality of broadcast contents is, for example, SI / PSI data. The contents selected by the viewer, such as which broadcast contents are transmitted in which TS packet, are selected by the viewer. This data is used when selecting and receiving a channel. Among these SI / PSI data, data presented to the viewer when the viewer selects a program is particularly called an EPG (Electronic Program Guide).
[0031]
The receiver uses this EPG data to present a program guide screen such as a television column of a newspaper to the viewer so that the viewer can easily select a program.
In this embodiment, SI / PSI data, except for a part, is treated as a signal that is not required to be protected by encryption (2) as a signal transmitted between the PDA 8 and the tuner module 1. Note that some of the SI / PSI data to be cryptographically protected is data that is used in free scramble broadcasting for protecting pay broadcasting and copyright, and for example, receiving equipment from the broadcasting station side. Alternatively, it is information that restricts the storage or copying of content in a device connected to the receiving device.
[0032]
If the data used for this pay broadcast or free scramble broadcast for copyright protection is altered when transmitted between the PDA 8 and the tuner module 1, it is copied or stored against the intention of the broadcast station. There is a concern that the copyright cannot be protected. Therefore, in this embodiment, the data used for the pay broadcasting and the free scramble broadcasting for protecting the copyright is processed as the signal (1) to be encrypted protected.
[0033]
Below, an example of the data used for these pay broadcasting and the free scramble broadcasting for protecting a copyright is given. It should be noted that, in the future, in the case where additional information is specified from the broadcasting station side that restricts the accumulation or copying of broadcast content by the receiving device and the device connected to the receiving device, 1) It is processed as a signal to be encrypted protected.
[0034]
(A) Digital copy control descriptor: Information for controlling copy generation in a digital recording device.
(B) Content usage descriptor: indicates information for controlling recording and output.
These digital copy control descriptors and content usage descriptors are currently specified for digital broadcasting in Japan. For details, please refer to the standard of the Japan Radio Industry Association “Program arrangement used for digital broadcasting. Refer to “Information (ARIB STD-B10 Version 3.4)”.
[0035]
Additional information for receiving other broadcast contents includes ECM data and EMM data as data in pay broadcasting and free scramble broadcasting for protecting copyright. The ECM data and EMM data are filtered by the filtering 7 of the tuner module 1 and given to the PDA 8. The PDA 8 uses the ECM data and EMM data as shown below to receive the scrambled broadcast. Is performed to determine whether or not to descramble.
[0036]
The EMM data is information related to the viewing contract (viewability) of each viewer. For example, in the case of pay broadcasting, the EMM data is information indicating which channel or which content can be viewed. This is data indicating the channel or which content can be viewed.
[0037]
Also, key data called a work key is defined as a part of the EMM data and given to the contracted viewer from the broadcast side, and the ECM data is encrypted or decrypted using the work key. It is like that.
[0038]
This EMM data is also encrypted on the broadcast side and transmitted to the receiver. The receiver uses the key data called a master key that is pre-installed (such as at the time of manufacture) on the receiver side for encryption and decryption. , Use. Note that if the master key is changed for each receiver, the broadcast side can control whether the receiver can be viewed individually. In the case of pay broadcasting, it is changed for each receiver. ing.
[0039]
On the other hand, in scrambled broadcasting for copyright protection of free broadcast content, which is called scrambled broadcasting for protecting copyright, the master key is not changed for each receiver, and each receiver manufacturer or receiver The master key is changed in a certain unit, such as for each model number. When a problem occurs in the copyright protection process, the broadcast station side controls so that viewing cannot be performed in units such as “for each receiver model number”.
[0040]
The ECM data is data used in combination with EMM data. This ECM data is, for example, information related to a channel or program content. In addition to scramble key data used for scrambled program content, condition data used for viewing availability such as broadcast date and time of the program content, etc. Consists of. By comparing the ECM data and the EMM data with the receiver, the receiver determines whether or not the program content can be viewed. If the program content can be viewed, the scramble key information in the ECM data is displayed. Used to descramble and view program content.
[0041]
In the present embodiment, the ECM data and EMM data described above are processed as signals to be encrypted and protected as (1) as signals transmitted between the PDA 8 and the tuner module 1. The ECM data and EMM data are originally encrypted and transmitted on the broadcasting station side, and are transmitted between the PDA 8 and the tuner module 1 in the encrypted state as transmitted. However, since it is easy to observe data between the PDA 8 and the tuner module 1 and the risk of analyzing the encryption of ECM data and EMM data increases, in order to reduce the risk, the signal to be protected from encryption (1) Process as.
[0042]
Further, in the present embodiment, ECM data in addition viewability determining processing using EMM data that shall be performed by PDA 8, de scrambled content is set to be performed in the descrambler 3 tuner module 1.
[0043]
Also, in broadcasts based on the MPEG system, broadcast contents other than desired broadcast contents to be selected by a viewer and displayed on a PC or the like may be multiplexed. For example, it is possible to include a plurality of broadcast contents in one TS. In this case, in this embodiment, the signal is classified as (1) a signal to be protected by encryption, (2) a signal that does not need to be encrypted, and (3) an unnecessary signal.
[0044]
First, EMM data and ECM data in the digital broadcast signal received from the antenna input unit 15 are input to the viewing permission determination unit 14 of the PDA 8 via the filtering 7. At this time, the program content selected by the viewer to be viewed or stored (stored) in the PDA 8 is processed as a signal to be encrypted and protected as a signal to be transmitted between the PDA 8 and the tuner module 1 (1).
[0045]
That is, the scramble key is transmitted to the descrambler 3 so as to encrypt the program content selected by the viewer by the viewing permission determination unit 14 of the PDA 8. The desired program content is descrambled by the descrambler 3 and then transmitted to the encryption processing means 4 for encryption. The encrypted encrypted data of the desired program content is transmitted to the decryption processing means 9 of the PDA 8 and decrypted. The decrypted desired program content is decoded by the MPEG decode 10 and copyrighted by the copyright protection process 10 and then output to the output unit 16 such as a display device.
[0046]
In addition, unselected program content multiplexed on a TS including program content selected by the viewer for viewing or storage (storage) in the PDA 8 is processed as an unnecessary signal of (3). In this case, since the content is not selected by the viewer, it is not transmitted between the PDA 8 and the tuner module 1. Specifically null packet of TS packet data of the program content without this selection (PID of the TS packet header portion is 0x1FFF) to or 0 filling processing to be Runado invalidates signaling the TS packet data. Since unnecessary data need not be subjected to encryption processing or decryption processing in this way, hardware or software resources required for the encryption processing means 4 of the tuner module 1 and hardware or software resources required for the decryption processing means 9 of the PDA 8 Can be saved.
[0047]
The other data is transmitted as it is from the tuner module 1 to the PDA 8 without being subjected to encryption processing as the signal (2) that does not need to be encrypted. In this way, the signal that does not need to be subjected to encryption processing does not need to be subjected to encryption processing or decryption processing, so that it is necessary for hardware or software resources required for the encryption processing means 4 of the tuner module 1 and the decryption processing means 9 of the PDA 8. Can save valuable hardware or software resources.
[0048]
FIG. 2 shows the relationship between data and processing handled in this embodiment.
As shown in FIG. 2, the program content selected (selected) as a TS packet is encrypted and transmitted as a signal that requires the encryption processing of (1).
Data used for copyright protection reception control, such as a copy control descriptor, of the SI / PSI packet as a TS packet is encrypted and transmitted as a signal requiring the encryption processing of (1).
[0049]
Other SI / PSI packets as TS packets are transmitted as they are as signals that do not require the encryption processing of (2).
The program content that is not selected (selected) is transmitted with a null packet or zero padding.
Through the above processing, only the minimum necessary data is encrypted, thereby saving the hardware or software resources required for the encryption processing means of the tuner module and the hardware or software resources required for the decryption processing means of the receiver. be able to.
[0050]
More specifically, as shown in FIG. 3, by classifying according to the scrambled state of the program content, hardware or software resources necessary for the encryption processing means of the tuner module and hardware or software necessary for the decryption processing means of the receiver. Wear resources can be saved.
[0051]
That is, among the program contents selected (selected), the scrambled contents and the data descrambled by the MULTI2 descrambler 3 shown in FIG. 1 are subjected to encryption processing as a signal requiring the encryption processing of (1). Even if the program content is selected (selected), the content that is broadcast without being scrambled is a signal that does not require the encryption processing of (2).
[0052]
【The invention's effect】
The present invention makes it possible to provide a tuner module that receives a digital broadcast and efficiently encrypts the digital broadcast signal.
[Brief description of the drawings]
FIG. 1 is a block diagram of a receiving apparatus in which a tuner module and a receiver are connected according to an embodiment of the present invention.
FIG. 2 is a table showing a relationship between content data handled by a tuner module according to an embodiment of the present invention and processing.
FIG. 3 is a table showing a relationship between content data handled by a tuner module according to an embodiment of the present invention and processing.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Tuner module 2 ... Demodulation means 3 ... Descrambler 4 ... Encryption processing means 5 ... Mutual authentication means 6 ... Encryption key generation means 7 for mutual authentication processing ... Filtering 8 ... Receiver 9 ... Cryptographic processing means 10 ... MPEAG decoding 11 ... Copyright protection processing 12 ... Mutual authentication processing means 13 ... Cryptographic key generation means 14 for mutual authentication processing ..Means for judging whether to view or not

Claims (3)

Demodulation means for demodulating a signal from an antenna for receiving digital broadcasting;
And Desukuranbu Le a demodulated signal by the demodulating means, the tuned with descrambled content, broadcast on a non-scrambled content is tuning, SI / PSI data used for the control of copyright protection, and de scrambler to output a transport stream including and copyright is not used to control the protective SI / PSI data, and
An authentication processing means for authenticating the receiver;
After mutual authentication with the receiver by the authentication processing means , the selected and descrambled content and the SI / PSI data used for copyright protection control are encrypted and broadcast in the unscrambled manner has been content was tuned, and the SI / PSI data is not used for the control of the copyright protection unencrypted, characterized by including a cryptographic processing section to send a transport stream to the receiver Tuner module.   A tuner module according to claim 1;
  A receiver having decoding processing means for decoding a transport stream transmitted from the tuner module, and an MPEG decoder for decoding the decoded transport stream;
  A receiving system comprising: Demodulation means for demodulating the signal from the antenna for receiving digital broadcasting, and Desukuranbu Le a signal demodulated by the demodulating means, which is channel selection being broadcast is tuned descrambled content, in a non-scrambled content, SI / PSI data is used for controlling the copyright protection, and is not used to control copyright protection SI / PSI data, de-scrambler to output a transport stream including encryption signals from the descrambler A tuner module having an encryption processing means for authenticating, an authentication processing means for authenticating the receiver, a decryption processing means for decoding the encrypted signal, an MPEG decoding processing means, and an authentication processing means for authenticating the device. When connected to a receiver and used as a digital broadcast receiver,
After the tuner module mutually authenticates with the receiver by the authentication processing means , the selected and descrambled content and the SI / PSI data used for the copyright protection control are encrypted , the broadcast on a non-scrambled content was tuned, and the SI / PSI data is not used for the control of the copyright protection unencrypted, characterized in that it sent as a transport stream to the receiver Encryption processing method.

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