JP2004173027A - Tuner module, and encipherment method using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tuner module which receives digital broadcast and efficiently enciphers the digital broadcasting signals. <P>SOLUTION: The tuner module is provided with: a demodulation means 2 for demodulating the signals from an antenna which receives digital broadcast, a descrambler 3 for descrambling signals demodulated by the demodulation means 2; an authentication processing means 5 for authenticating a receiver 8; and an encipherment means 4 for enciphering signals from the descrambler 3, which includes contents selectively indicated from the receiver 8, and invalidating signals from the descrambler 3, which include contents which are not selectively indicated from the receiver 8, after mutual authentication with the receiver 8 by the authentication processing means 5. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a tuner module having a copyright protection function.
[0002]
[Prior art]
In IEEE 1394, which is a bus standard for transmitting digital broadcast signals between devices, DTCP (5C Digital Transmission Content Protection) specifications for encrypting and protecting transmitted signals are specified (see Non-Patent Document 1).
[0003]
According to the publication, it is described that when 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]
[Retrieved 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 DTCP specification, when encrypting a digital broadcast signal, each device encrypts all contents and control signals included in the digital broadcast signal. There is a problem that hardware resources for decoding processing and software resources for controlling the hardware are required extra.
[0006]
SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and has as its object to provide a tuner module that receives 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 demodulating means for demodulating a signal from an antenna for receiving digital broadcasting,
A descrambler for descrambling the signal demodulated by the demodulation means,
Authentication processing means for authenticating the receiver;
After mutual authentication with the receiver by the authentication processing means, encrypts a signal from the descrambler including the content selected and supported by the receiver, and includes the content not selected and instructed by the receiver. And a cryptographic processing means for invalidating the signal from the descrambler.
[0008]
At this time, it is preferable that the encryption processing means transmits a signal that does not need to be copyright protected to the receiver as it is.
It is preferable that nullification is performed by null packetization or zero padding.
Preferably, the tuner module can be connected to the display device using a PC card, CompactFlash (registered trademark), USB, or PCI bus.
[0009]
In this way, for example, when a tuner module having a built-in 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 assistant), the hardware of the general-purpose device is used. Software resources and software resources can be suppressed.
[0010]
Also, the present invention provides a demodulating means for demodulating a signal from an antenna for receiving a digital broadcast, a descrambler for descrambling a signal demodulated by the demodulating means, an encryption processing means for encrypting a signal from the descrambler, and A tuner module including authentication processing means for authenticating a device, and a receiver including decoding processing means for decoding at least an encrypted signal, MPEG decoding processing means, and authentication processing means for authenticating the device; When connected and used as a digital broadcast receiver,
[0011]
The tuner module, after mutually authenticating with the receiver by the authentication processing means, encrypts the content selected and instructed by the receiver by the encryption processing means, and encrypts the content not selected by the receiver. The present invention provides an encryption processing method characterized in that an invalid signal is transmitted 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 to the receiver as it is.
It is preferable that nullification is performed by null packetization or zero padding.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the following embodiments.
FIG. 1 is a block diagram of a digital broadcast receiving apparatus when the tuner module according to the embodiment of the present invention is connected to a general-purpose device such as a PC (personal computer) or PDA (personal digital assistant).
[0014]
As shown in FIG. 1, a tuner module 1 of the present invention includes an input unit 15 from an antenna, a demodulation unit 2 for demodulating a digital broadcast signal input from the input unit 15 from the antenna, and a demodulation unit. 2 includes a descrambler 3 for descrambling the signal demodulated by the descrambler 2 and encryption processing means 4 for encrypting the signal descrambled by the descrambler 3. Also, an authentication processing unit 5 for performing mutual authentication processing with other devices, an encryption key storage (or generation generated by a predetermined method) unit 6 for mutual authentication processing, an EMM, ECM signal And a filtering 7 for processing. Although detailed description is omitted, the demodulation means 2 also performs channel selection, error correction, and the like.
[0015]
Further, the receiver 8 includes a decryption processing unit 9 for decrypting the encrypted signal, an MPEG decoder 10, a copyright protection processing unit 11, an authentication processing unit 12 for performing a mutual authentication process, a mutual authentication process, The apparatus includes a processing encryption key storage (or generation generated by a predetermined method) 13 and a viewability determination unit 14.
[0016]
The tuner module 1 can be used, for example, by inserting it into a compact flash (registered trademark) slot of a PC or PDA. The tuner module 1 can be connected to the receiver 8 implemented by a PC or PDA by using 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 the copyright because it is necessary to prevent illegal copying of the content.
[0017]
In the following description, it is assumed that a PDA is used as the receiver 8 and a PC card bus is used as the general-purpose I / F.
As shown in FIG. 1, when the tuner module 1 and the PDA 8 are connected and 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]
Mutual authentication is performed, for example, by using a mutual authentication key shared between the PDA 8 and the tuner module 1 in advance, and is processed by the following procedure using, for example, a common key cryptosystem.
[0019]
First, a random number is transmitted from the authentication processing unit 12 of the PDA 8 to the authentication processing unit 5 of the tuner module 1. The tuner module 1 encrypts the random number using a mutual authentication processing encryption key from the mutual authentication processing encryption key storage unit 6. Then, the encrypted random number is transmitted to the authentication processing unit 12 of the PDA 8 via the authentication processing unit 5.
[0020]
Next, the PDA 8 compares the encrypted random number sent from the tuner module 1 with an encrypted random number obtained by encrypting the random number by the PDA 8 itself. As a result, if the two data match, the PDA 8 confirms that the tuner module 1 has a predetermined mutual authentication key.
[0021]
In the above procedure, first, the case where the random number is 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 a mutual authentication processing encryption key obtained from the mutual authentication processing encryption storage unit 13. Then, the encrypted random number is transmitted to the authentication processing unit 6 of the tuner module 1 via the authentication processing unit 12.
[0023]
Next, the tuner module 1 compares the encrypted random number sent from the PDA 8 with the encrypted random number obtained by encrypting the random number by the tuner module 1 itself. As a result, when the two data match, it is confirmed from the tuner module 1 that the PDA 8 has a predetermined mutual authentication key.
[0024]
Thus, the 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 use it for the current time, and the security is maintained.
[0025]
Here, it is assumed that the encryption key for the mutual authentication process is shared in advance secretly between the tuner module 1 and the PDA.
Further, the method of mutual authentication is not limited to the method described here, and for example, a method using a public key cryptosystem 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 referred to here is a key generated so as to be different each time the mutual authentication process is performed, for example, a key generated using a random number.
[0026]
In other words, 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, a case where the session key is generated by the PDA 8 or a case where the session key is generated by the tuner module 1 or a case where the session key is generated by combining the data generated by the PDA 8 and the tuner module 1 can be considered.
[0027]
Further, after sharing a session key between the PDA 8 and the tuner module 1, the 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.
Note that the encryption process may be performed by preparing a coprocessor different from the main CPU in the PDA 8.
Next, a method of 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 an antenna input is transmitted to the PDA 8 after being demodulated and encrypted by the tuner module 1. The form of this broadcast signal is a transport stream (hereinafter TS). TS is a standard defined by the MPEG system and will not be described in detail. However, TS 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. In addition, one TS can include a plurality of broadcast contents.
[0030]
The additional information for receiving a plurality of broadcast contents is, for example, SI / PSI data, and the viewer selects a program such as which broadcast contents are transmitted by which TS packet, and the receiver selects the contents. Is used to select and receive 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 the EPG data to present a program guide screen such as a television section of a newspaper to a viewer, so that the viewer can easily select a program.
In this embodiment, except for a part, the SI / PSI data is handled as a signal transmitted between the PDA 8 and the tuner module 1 as a signal (2) that does not need to be encrypted. The part of the SI / PSI data to be encrypted is data used in pay broadcasting or free scramble broadcasting for protecting copyrights. Alternatively, the information is information for restricting storage or copying of content by a device connected to the receiving device.
[0032]
If data used for this pay broadcast or free scramble broadcast for protecting copyright is falsified when transmitted between the PDA 8 and the tuner module 1, the data is copied or stored against the will of the broadcasting station. For example, there is a concern that copyright cannot be protected. Therefore, in the present embodiment, the data used for the pay broadcast and the free scramble broadcast for protecting the copyright are processed as the signal (1) to be encrypted.
[0033]
The following is an example of data used in these pay broadcasts and free scramble broadcasts for protecting copyrights. In the case where the broadcast station additionally specifies information for restricting accumulation or copying of broadcast content by a receiving device and a device connected to the receiving device in the future, similarly, ( It is processed as a signal to be protected in 1).
[0034]
(A) Digital copy control descriptor: Indicates information for controlling a 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, refer to the standard Information (ARIB STD-B10 Version 3.4) ".
[0035]
In addition, as additional information for receiving broadcast contents, there are ECM data and EMM data in data in paid broadcasts and free scrambled broadcasts for protecting copyrights. The ECM data and the 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 the EMM data to receive the scrambled broadcast as described below. And a viewing permission / prohibition determination process 14 for determining whether or not to descramble.
[0036]
The EMM data is information relating to the viewing contract (viewing permission / prohibition) of each individual viewer. For example, in the case of pay broadcasting, it is information indicating which channel or content can be viewed, and the term of the contract and the contract This data indicates a channel or what content can be viewed.
[0037]
Also, what is defined as a part of the EMM data and given from the broadcasting side to a viewer with a contract is key data called a work key, and performs encryption processing or decryption processing on ECM data using the work key. It has become.
[0038]
The EMM data is also encrypted on the broadcast side and transmitted to the receiver. However, the EMM data is decrypted and decrypted by the receiver using key data called a master key which is pre-installed (at the time of manufacture or the like) on the receiver side. , Use. If the master key is changed for each receiver, the broadcasting side will be able to control whether or not each receiver can be viewed, and in the case of pay broadcasting, it will be changed for each receiver. ing.
[0039]
On the other hand, in a scrambled broadcast for protecting the copyright, which is a scrambled broadcast for protecting the copyright of free broadcast content, the master key is not changed for each receiver, but for each receiver manufacturer or receiver. The master key is changed in a certain unit such as each model number. When a problem occurs in the copyright protection processing, the broadcast station controls so that the viewing cannot be performed in units such as “for each receiver model number”.
[0040]
ECM data is data used in combination with EMM data. The ECM data is, for example, information related to the channel or the program content. In addition to the scramble key data used for the scrambled program content, condition data used for viewing availability such as the broadcast date and time of the program content, etc. It consists of. By comparing the ECM data with the EMM data at the receiver, the receiver determines whether or not the program content can be viewed. When the program content can be viewed, the scramble key information in the ECM data is changed. Used to descramble and view the program content.
[0041]
In the present embodiment, the ECM data and EMM data described above are processed as a signal to be encrypted and protected in (1) as a signal transmitted between the PDA 8 and the tuner module 1. The ECM data and the EMM data are originally encrypted on the broadcast station side and transmitted, and transmitted between the PDA 8 and the tuner module 1 in an encrypted state as transmitted. However, it is easy to observe the data between the PDA 8 and the tuner module 1, and the risk of analyzing the encryption of the ECM data and EMM data increases. Process as
[0042]
Further, in the present embodiment, the viewing permission / prohibition determination process using the ECM data and the EMM data is performed by the PDA 8, and descramble of the content is performed by the descrambler 3 of the tuner module 1.
[0043]
Also, in the broadcasting by the MPEG system, there are cases where broadcast contents other than desired broadcast contents to be selected by a viewer and displayed on a PC or the like are multiplexed. For example, one TS can include a plurality of broadcast contents. In this case, in this embodiment, the signals are classified into (1) a signal to be protected by encryption, (2) a signal that does not need to be subjected to encryption processing, and (3) as follows.
[0044]
First, the EMM data and the ECM data of the digital broadcast signal received from the antenna input unit 15 are input to the viewability determining 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 in (1) as a signal transmitted between the PDA 8 and the tuner module 1.
[0045]
That is, the scramble key is transmitted to the descrambler 3 so that the program content selected by the viewer is encrypted by the viewability determining means 14 of the PDA 8. After the desired program content is descrambled by the descrambler 3, it is transmitted to the encryption processing means 4 and encrypted. The encrypted encrypted program 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 decoder 10, is copyright-protected by the copyright protection processing 10, and is output to the output unit 16 such as a display device.
[0046]
Unselected program contents multiplexed on a TS including program contents selected by the viewer to be viewed or stored (stored) in the PDA 8 are processed as unnecessary signals in (3). In this case, since the content is not selected by the viewer, it is assumed that the content is not transmitted between the PDA 8 and the tuner module 1. Specifically, the TS packet data of the unselected program content is set to a null packet (the PID of the TS packet header is 0x1FFF), or zero-fill processing is performed. Since unnecessary data does not need to be subjected to encryption processing and decryption processing, 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 are unnecessary. Can be saved.
[0047]
The other data is transmitted from the tuner module 1 to the PDA 8 without performing the encryption processing as it is as a signal that does not need to be subjected to the encryption processing of (2). In this manner, signals that do not need to be subjected to encryption processing need not be subjected to encryption processing and decryption processing, so that hardware or software resources required for encryption processing means 4 of tuner module 1 and decryption processing means 9 of PDA 8 are required. Hardware or software resources can be saved.
[0048]
FIG. 2 shows a relationship between data handled in this embodiment and processing.
As shown in FIG. 2, the program content selected (selected) as a TS packet is subjected to encryption processing as a signal requiring the encryption processing of (1) and transmitted.
Data used for reception control of copyright protection, such as a copy control descriptor, of the SI / PSI packet as a TS packet is subjected to encryption processing as a signal requiring the encryption processing of (1) and transmitted.
[0049]
Other SI / PSI packets as TS packets are transmitted as they are as signals requiring no encryption processing in (2).
The program content that is not selected (selected) is transmitted as a null packet or a 0-embedding process.
With the above processing, only the minimum necessary data is encrypted, thereby saving hardware or software resources required for the encryption processing means of the tuner module and 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 scramble state of the program contents, 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 are obtained. Wear resources can be saved.
[0051]
That is, among the program contents selected (selected), the scrambled contents, the data descrambled by the MULTI2 descrambler 3 shown in FIG. 1 are subjected to encryption processing as signals requiring the encryption processing of (1). Even if the program content is selected (selected), the content broadcast without scrambling 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 according to an embodiment of the present invention are connected to each other.
FIG. 2 is a table showing a relationship between content data handled by a tuner module and processing according to the embodiment of the present invention.
FIG. 3 is a table showing a relationship between processing and content data handled by the tuner module according to the embodiment of the present invention.
[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 7 ... Filtering 8 Receiver 9 Encryption processing means 10 MPEAG decoding 11 Copyright protection processing 12 Mutual authentication processing means 13 Encryption key generation means 14 for mutual authentication processing ..Viewing availability determination means

Claims (6)

Demodulation means for demodulating a signal from an antenna for receiving digital broadcasting,
A descrambler for descrambling the signal demodulated by the demodulation means,
Authentication processing means for authenticating the receiver;
After mutual authentication with the receiver by the authentication processing means, encrypts a signal from the descrambler including the content selected and supported by the receiver, and includes the content not selected and instructed by the receiver. A tuner module comprising: a cryptographic processor for invalidating a signal from the descrambler. 2. The tuner module according to claim 1, wherein the encryption processing unit transmits a signal that does not need to be copyright protected to the receiver as it is. The tuner module according to claim 1, wherein the signal nullification is performed by null packetization or zero padding. Demodulation means for demodulating a signal from an antenna for receiving a digital broadcast, a descrambler for descrambling the signal demodulated by the demodulation means, an encryption processing means for encrypting a signal from the descrambler, and an authentication for authenticating a device. Receiving a digital broadcast by connecting to a tuner module having a processing means, and a receiver having a decoding processing means for decoding at least an encrypted signal, an MPEG decoding processing means and an authentication processing means for authenticating a device; When used as a container,
The tuner module, after mutually authenticating with the receiver by the authentication processing means, encrypts the content selected and instructed by the receiver by the encryption processing means, and encrypts the content not selected by the receiver. An encryption processing method, comprising converting the signal to an invalid signal and transmitting the signal to the receiver. 5. The encryption processing method according to claim 4, wherein the encryption processing means transmits a signal that does not need to be copyright protected to the receiver as it is. 6. The encryption processing method according to claim 4, wherein the non-signaling is performed by null packetization or zero padding.

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