JP4422787B2 - Digital broadcasting system and content receiving apparatus - Google Patents

Description

  The present invention relates to a digital broadcasting system and a content receiving apparatus that prevent or transmit illegal copies that are part of rights management protection of content, particularly digital content.

  2. Description of the Related Art Conventionally, in a digital broadcasting system that transmits and receives content (particularly digital content), a digital broadcast receiving device that receives the digital content is used as a digital copy control descriptor in a PMT (Program Map Table) included in the received digital content. In accordance with the multiplexed copy control information, copy control of digital content to a storage device (or other storage medium) provided (attached) to the receiving device is performed.

  In this digital broadcasting system, even in the case of a limited reception method (for example, see Non-Patent Document 1), digital content (video, audio) is encoded (encoded) into a transport stream packet and then encrypted (encoded). Although scrambled), the PMT is not encrypted, and the digital copy control descriptor (copy control information) is transmitted in the form of plain text (information that is not encoded or encrypted).

Radio Industry Association (ARIB) Standard "Program Arrangement Information Used for Digital Broadcasting" (ARIB STD-B10), P108, P147

  However, in the conventional digital broadcasting system, the digital copy control descriptor (copy control information) is tampered with illegally, for example, the digital content digital copy control descriptor (copy control information) is “copy prohibited”. There is a problem in that unauthorized copying may occur by making “copy free” and storing in a storage device (another storage medium).

  SUMMARY OF THE INVENTION An object of the present invention is to provide a digital broadcasting system and a content receiving apparatus that can solve the above-described problems of the prior art and prevent unauthorized copying of content.

In order to achieve the above-described object, the present invention has the following configuration.
The digital broadcast system according to claim 1 is a digital broadcast system including a content transmission device and a content reception device that transmit and receive content indicating video and audio, wherein the content transmission device uses the content as a stream format. Content encryption means for encrypting the audio content stream with the first encryption key to obtain encrypted content, and information for controlling the number of times the provider providing the content copies the content on the receiving side receiving the content Copy control information processing means for processing copy control information of a certain plaintext into function calculation information calculated by a function for generating a code for falsification detection that shortens the information to a fixed size value, and the first encryption key Related information that can identify the business operator and the function calculation information A first encryption key encryption means for encrypting with the second encryption key and using the ECM to be used when reproducing the video and audio on the receiving side; and multiplexing the ECM packet of the ECM on the video / audio packet of the encrypted content Multiplex transmission means for transmitting the encrypted multi-encrypted content in a transport stream format in which the plaintext copy control information is multiplexed in the PMT portion, and the content receiving device has the transport stream format Receiving separation that receives the multiple encrypted content and separates it into a video / audio packet of the encrypted content multiplexed in the multiple encrypted content and plain text copy control information included in the PMT, and an ECM packet of the ECM And the ECM separated by the reception separation means are provided in the content transmission device. A first encryption key related information decryption means for decrypting with a second encryption key similar to the second encryption key, and obtaining a first encryption key and function operation information contained in the ECM; and the reception separating means The plaintext copy control information is extracted from the video / audio packet of the encrypted content separated in step 1 and the plaintext copy control information included in the PMT, and the encrypted content and the copy control information are output to the content decryption output unit. A copy control information extracting means for outputting the copy control information to the content storage means and the outside; and a code for detecting the alteration provided in the content transmission apparatus, the copy control information for the extracted plaintext. Is calculated by a function similar to the function for generating the function and is used as comparison function calculation information, and the first encryption key related information decryption means The obtained function calculation information is compared with the comparison function calculation information calculated by the calculation means, and if they match, a transmission permission signal indicating that the copy control information extracted from the PMT has not been falsified When the comparison result is output, on the other hand, if they do not match, a function calculation information comparison unit that outputs a transmission disable signal indicating that the data has been tampered with is output as a comparison result, and the transmission permission signal is input from the function calculation information comparison unit The first encryption key is sent out, and when the send disable signal is inputted, the first encryption key sending control means for stopping sending the first encryption key and the copy control information extracting means output it. Receiving the encrypted content and copy control information input, and decrypting the encrypted content with the first encryption key sent by the first encryption key sending control means Content decryption output means for performing copy control based on the received copy control information when the decrypted content or the encrypted content is copied to an external storage device, and the content decryption When the decrypted content or the encrypted content output from the output unit is stored inside, if the copy control information extracted by the copy control information extraction unit indicates copy prohibition, it is not stored. A content storage unit that stores the copy control information according to the copy control information when the extracted copy control information indicates permission or the number of copies.

  According to such a configuration, in the content transmission apparatus, first, the content is encrypted by the content encryption unit with the first encryption key to be an encrypted content. Further, the copy control information processing means calculates the plain text copy control information with a function for generating a code for detecting alteration that shortens the information to a fixed size value, and processes the information into function calculation information. In this case, a function for generating a code for detecting falsification by shortening information to a fixed size value is obtained by calculating a certain information A by the function, and reducing the data amount of the information A and decoding it. For example, a hash function can be mentioned. Then, the first encryption key encryption unit encrypts the first encryption key and the function calculation information with the second encryption key, and the ECM is used when the video and audio are reproduced on the receiving side. After that, the multiplexed transmission content is multiplexed and transmitted in the form of a transport stream in which plaintext copy control information is multiplexed in the PMT portion. The

  The related information that includes the first encryption key and can identify the provider that provided the content is the first encryption key and the ID of the provider that provided the content, that is, identification information of a broadcasting station, a content production company, etc. It is information including.

In addition, processing content on the transmission side is usually referred to as “scramble” so that only limited recipients on the reception side can view it, but here it is expressed in a unified manner using the phrase “encryption”. ing.

Furthermore, the first encryption key indicates, for example, a scramble key that is changed in units of several seconds with the elapsed time, and the second encryption key indicates, for example, a work key that is held for a longer time than the content duration. Is.

  In the content receiving apparatus, first, the reception-separating means receives the multiplexed encrypted content in the transport stream format as a video / audio packet of the encrypted content and plain text copy control information included in the PMT, and the ECM ECM. Separated into packets. Subsequently, the ECM is decrypted with the second encryption key by the first encryption key related information decrypting means, and the first encryption key and the function calculation information included in the ECM are acquired. Then, the copy control information extraction unit extracts the plain text copy control information from the video / audio packet of the encrypted content separated by the reception separation unit and the PMT, and the encrypted content and the copy control information are output by decrypting the content. The copy control information is output to the content storage means and the outside. Then, the calculation means calculates the plaintext copy control information extracted from the PMT with a function similar to a function for generating a code for falsification detection provided in the content transmission device, and compares the function calculation information for comparison with Is done. The function calculation information comparing means compares the function calculation information decrypted from the ECM and the comparison function calculation information, and based on the comparison result, the first encryption key sending control means controls the sending of the first encryption key. The Thereafter, the content decryption output means decrypts the encrypted content with the first encryption key and outputs the decrypted content. In addition, the content decryption output unit accepts the input of the encrypted content and copy control information output from the copy control information extraction unit, and copies the decrypted content or encrypted content to an external storage device. Copy control is performed based on the received copy control information. When the decrypted content or the encrypted content output from the content decryption output unit is stored therein, and the copy control information extracted by the copy control information extraction unit indicates copy prohibition If the extracted copy control information indicates permission of copying or the number of times of copying without accumulating in the content accumulating unit, it is accumulated in the content accumulating unit according to the copy control information.

  The content receiving apparatus according to claim 2 includes a first encryption key for encrypting content indicating video and audio, and related information that can identify a business provider that provides the content, and fixing the information by shortening the information. Function calculation information obtained by processing plain text copy control information, which is information for controlling the number of times the content is copied, by a function that generates a code for detecting falsification as a size value, and the second encryption A multi-encrypted content obtained by encrypting an ECM packet of an ECM that is configured to be encrypted with a key and used for reproducing the video and audio and a video / audio packet of the encrypted content encrypted with the first encryption key. , A content receiver that receives the plaintext copy control information in the PMT portion in a transport stream format. Receiving the multiplexed encrypted content in the transport stream format, the video / audio packet of the encrypted content multiplexed in the multiplexed encrypted content, the plain text copy control information included in the PMT, the ECM A reception separation unit that separates the ECM packet, and the ECM separated by the reception separation unit is decrypted with a second encryption key similar to the second encryption key provided on the transmission side, and is included in the ECM. First encryption key related information decrypting means for obtaining the first encryption key and function operation information, and the video / audio packet of the encrypted content separated by the reception separating means and the plain text copy control information included in the PMT , Extracting the plaintext copy control information and sending the encrypted content and copy control information to the content decryption output means The copy control information extraction means for outputting the copy control information to the content storage means and the outside, and the extracted plaintext copy control information as a code for detecting the alteration provided on the transmission side. An arithmetic unit that performs an operation using the same function as the function to be generated and sets it as comparison function operation information, the function operation information acquired by the first encryption key related information decryption unit, and a comparison operation performed by the operation unit When the function operation information is compared, if it matches, a transmission permission signal indicating that the copy control information extracted from the PMT has not been tampered with is output as a comparison result. A function calculation information comparison means for outputting a transmission disable signal indicating the comparison result, and when the transmission permission signal is input from the function calculation information comparison means, A first encryption key transmission control means for stopping transmission of the first encryption key when the transmission disable signal is input, and the encryption output from the copy control information extraction means Accepts input of content and copy control information, decrypts and outputs the encrypted content with the first encryption key transmitted by the first encryption key transmission control means, and outputs the decrypted content or the encrypted Content decryption output means for performing copy control based on the received copy control information when copying content to an external storage device, and the decrypted content or the encryption output from the content decryption output means The copy control information extracted by the copy control information extracting means indicates that copying is prohibited when the digitized content is stored inside Not accumulated in the case, characterized in that it comprises a content storage section for storing in accordance with the copy control information when the copy control information the extracted indicates the number of allowed or copy of copy.

  According to such a configuration, first, in the reception separation unit, the received encrypted content in the transport stream format is the encrypted audio / video packet of the encrypted content and the plain text copy control information included in the PMT, and the ECM ECM packet. And separated. Subsequently, the ECM is decrypted with the second encryption key by the first encryption key related information decrypting means, and the first encryption key and the function calculation information included in the ECM are acquired. Then, the copy control information extraction unit extracts the plain text copy control information from the video / audio packet of the encrypted content separated by the reception separation unit and the PMT, and the encrypted content and the copy control information are output by decrypting the content The copy control information is output to the content storage means and the outside. Then, a plain text copy control extracted from the PMT with a function similar to a function for generating a code for detecting falsification by shortening the information to a fixed size value provided in the transmission side by the calculation means Information is calculated and used as comparison function calculation information. The function calculation information comparing means compares the function calculation information decrypted from the ECM and the comparison function calculation information, and based on the comparison result, the first encryption key sending control means controls the sending of the first encryption key. The Thereafter, the content decryption output means decrypts the encrypted content with the first encryption key and outputs the decrypted content. In addition, the content decryption output unit accepts input of the encrypted content and copy control information output from the copy control information extraction unit, and copies the decrypted content or encrypted content to an external storage device. Copy control is performed based on the received copy control information. When the decrypted content or the encrypted content output from the content decryption output unit is stored therein, and the copy control information extracted by the copy control information extraction unit indicates copy prohibition If the extracted copy control information indicates permission of copying or the number of times of copying without storing in the content storage unit, it is stored in the content storage unit according to the copy control information.

  In the reception separation means, the received multiple encrypted contents in the transport stream format are separated into video / audio packets of the encrypted contents, plain text copy control information included in the PMT, and ECM ECM packets. This is because only ECM is handled in a security module in which stored information cannot be read from the outside.

  Here, for the sake of convenience, the expression of being decrypted with the first encryption key and the second encryption key is used, but actually, the first encryption key and the second encryption key are, for example, a scramble key, a work key, and the like. And so on.

  According to the first aspect of the present invention, in the content transmission device, the content is encrypted with the first encryption key to be encrypted content. The plain text copy control information is calculated by a function that generates a code for detecting falsification, and processed into function calculation information. Then, the first encryption key and the function calculation information are encrypted with the second encryption key, and used as an ECM used when video and audio are reproduced on the receiving side. Thereafter, the multiplexed content obtained by multiplexing the encrypted content and the ECM is transmitted in a transport stream format in which plain text copy control information is multiplexed in the PMT portion. For this reason, in the content receiving device, the function calculation information multiplexed as the ECM in the transport stream format multiple encrypted content and the function similar to the function for generating the code for detecting falsification on the transmission side, the PMT The plaintext copy control information included in the data is compared with the information obtained by the calculation on the receiving side, and it is possible to determine whether or not the content is usable based on the comparison result. Thereby, it is possible to prevent unauthorized copying of content or generation of content including unauthorized copy control information.

  According to the second aspect of the present invention, the received multi-encrypted content in the transport stream format is separated into the video / audio packet of the encrypted content and the plain text copy control information included in the PMT and the ECM ECM packet. Is done. Subsequently, the ECM is decrypted with the second encryption key, and the first encryption key and the function calculation information included in the ECM are obtained. Also, plain text copy control information is extracted from the PMT of the encrypted content. The plain text copy control information extracted from the PMT is calculated by a function similar to a function for generating a falsification detection code provided on the transmission side, and is used as comparison function calculation information. The function calculation information acquired from the ECM is compared with the comparison function calculation information, and the transmission of the first encryption key is controlled based on the comparison result. Thereafter, the encrypted content is decrypted with the first encryption key and output. For this reason, a function similar to a function for generating a code for detecting falsification provided on the transmission side with function operation information multiplexed as ECM in the multiplexed encrypted content and plain text copy control information extracted from the PMT Is compared with the result obtained by the calculation, and based on the comparison result, it can be determined whether or not the content is usable. Thereby, it is possible to prevent unauthorized copying of content or generation of content including unauthorized copy control information.

It is a block diagram of the content transmission apparatus which is one embodiment by this invention. It is a block diagram of the content receiver which is one embodiment by this invention. 3 is a flowchart illustrating an operation of the content transmission apparatus illustrated in FIG. 1. 3 is a flowchart for explaining the operation of the content receiving apparatus shown in FIG. 2. 5 is a flowchart for explaining the operation of the content receiving device shown in FIG. 2 (continuation of FIG. 4). It is a block diagram of the content transmission apparatus which is embodiment of the reference example of this invention. It is a block diagram of the content receiver which is embodiment of the reference example of this invention. It is a flowchart explaining operation | movement of the content transmission apparatus shown in FIG. It is a flowchart explaining operation | movement of the content receiver shown in FIG. 10 is a flowchart for explaining the operation of the content receiving apparatus shown in FIG. 7 (continuation of FIG. 9). It is a figure explaining the example of the digital copy control descriptor.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.
(Configuration of content transmission apparatus: first embodiment)
With reference to the block diagram of the content transmission device shown in FIG. 1, the configuration of the content transmission device (first embodiment) will be described. As shown in FIG. 1, the content transmission apparatus 1 includes an MPEG2 encoding unit 3, a scramble unit 5, an ECM generation unit 7, a copy control information Mc generation unit 9, a hash function calculation unit 11, and a multiplexing unit 13. And.

  The content transmitting device 1 transmits the content by enabling the copy (duplication) control when the content is received (reproduced) on the receiving side that has received the content (digital content, hereinafter referred to as content in a unified manner). To do.

  The MPEG2 encoding unit 3 encodes (encodes) the video / audio Mav (content), which is the input video / audio content, to generate a video / audio content stream (TS) in the MPEG2 format. Encoding is to generate a digital code from a video / audio signal, and the purpose of encoding is to compress the original signal by converting the analog signal into a digital signal or reducing the redundancy of the digital signal. And reducing the amount of data transmitted or stored.

  The scrambler 5 scrambles the video / audio content stream (TS) encoded by the MPEG2 encoder 3 with the scramble key Ks to generate encrypted content (E (Mav, Ks)). The content transmitting apparatus 1 is provided with a scramble key generating means (not shown) for generating a scramble key Ks. Scramble refers to encryption of a stream format signal, and the scramble key Ks is an encryption key that is changed in units of several seconds (generally about 1 second) with the elapsed time of content. The scramble unit 5 corresponds to the content encryption means described in the claims, and the scramble key Ks corresponds to the first encryption key.

  The ECM generator 7 encrypts the related information including the scramble key Ks and the hash value H (Mc) calculated by the hash function calculator 11 with the work key Kw, and reproduces the video / audio Mav on the receiving side. The first encryption key related information (E (ECM, Kw)) to be used is generated. The related information including the scramble key Ks is information including the scramble key Ks and the ID of the provider that provided the content, that is, the identification information of the broadcasting station, the content production company, and the like. The hash value H (Mc) is generated data obtained by calculating original text data (original information, original text, or plain text) with a hash function (described later), and it is impossible to estimate the original text data from this generated data. It is possible. The hash value H (Mc) corresponds to the function calculation information described in the claims.

  The first encryption key related information is a so-called ECM (Entirement Control Message: common information), and this first encryption key related information (E (ECM, Kw)) is encrypted by the content receiving device (described later) on the receiving side. This is used when decrypting encrypted content. The work key Kw is an encryption key that is commonly held for a long period of time between the content transmitting apparatus 1 that is the transmitting side and the content receiving apparatus that is the receiving side (described later). The ECM is composed of information related to content, key information for descrambling, and the like, and includes an encrypted portion that is encrypted and a non-encrypted portion that is not encrypted. The work key Kw corresponds to the second encryption key described in the claims.

  The copy control information Mc generating unit 9 generates copy control information Mc according to the intention of the content sender side (broadcast station side, content producer side). Information for controlling copying (duplication) of content on the receiving side, such as “prohibited”, “one generation of copying is possible (one copying is possible)”, and “copying is free”. The copy control information Mc is binary information of several tens of bytes.

  The hash function calculation unit 11 calculates the copy control information Mc generated by the copy control information Mc generation unit 9 using a hash function, generates a hash value H (Mc), and outputs the hash value H (Mc) to the ECM generation unit 7. The hash function is a function for compressing original text data of an arbitrary length into generated data of a fixed length. For example, a hash function called SHA-1 or MD5 is representative, and these SHA-1 and Both MD5 are one-way functions and make it impossible to infer original text data from generated data. The hash function calculation unit 11 corresponds to the copy control information processing means described in the claims, and the hash value H (Mc) is the function calculation described in the claims. It corresponds to information.

  The multiplexing unit 13 converts the encrypted content obtained by multiplexing the encrypted content (E (Mav, Ks)), the first encryption key related information (E (ECM, Kw)), and the copy control information into the MPEG2 trans It is sent in the port stream format. Further, the multiplexing unit 13 can also multiplex and transmit data broadcast content (not shown) to the multiplexed encrypted content. Note that the copy control information Mc is multiplexed in a PMT (Program Map Table) of the video / audio content stream (TS). Further, the multiplexing unit 13 corresponds to the multiple sending means described in the claims.

  According to the content transmitting apparatus 1, the scramble unit 5 scrambles the video / audio content stream (TS) with the scramble key Ks to obtain the encrypted content (E (Mav, Ks)). Further, the copy control information Mc generated by the copy control information Mc generating unit 9 is calculated by the hash function calculating unit 11, and a hash value H (Mc) is generated. Then, the ECM generation unit 7 encrypts the related information including the scramble key Ks and the hash value H (Mc) of the copy control information Mc with the work key Kw, and the first encryption key related information (E (ECM, Kw )). Thereafter, the multiplexing unit 13 multiplexes the encrypted content (E (Mav, Ks)), the first encryption key related information (E (ECM, Kw)), and the copy control information Mc to multiplex encryption. Output as content.

  For this reason, on the receiving side, copy control is performed with the hash value H (Mc) multiplexed in the multiplex encrypted content and a hash function similar to the hash function provided in the hash function computing unit 11 on the transmitting side on the receiving side. If the hash value H (Mc) obtained by calculating the information Mc is compared, it can be determined whether or not the video / audio Mav (content) is available based on the comparison result.

  That is, if the comparison result shows that the multiplexed hash value H (Mc) matches the hash value H (Mc) calculated on the receiving side, the copy control information Mc has not been tampered with, and the video and audio Use of Mav (content) is permitted. If the hash value H (Mc) multiplexed and the hash value H (Mc) calculated on the receiving side do not match, the copy control information Mc has been falsified, and the video / audio Mav (content) Use is not permitted.

  Accordingly, it is possible to prevent illegal copying of the video / audio Mav (content) or generation of the video / audio Mav (content) including illegal copy control information.

(Configuration of content receiving apparatus: first embodiment)
Next, the configuration of the content receiving apparatus (first embodiment) will be described with reference to the block diagram of the content receiving apparatus shown in FIG. As shown in FIG. 2, the content receiving apparatus 21 includes a reception separating unit 23, a copy control information Mc extracting unit 25, a hash function calculating unit 27, a security module 29, a descrambling unit 37, and an MPEG2 decoding unit. 39 and a content storage unit 41.

  The content reception device 21 receives the multiplexed encrypted content transmitted from the content transmission device 1 on the transmission side (see FIG. 1), and transmits the copy control information Mc multiplexed on the multiple encrypted content to the content on the transmission side. It is detected that the copy control information Mc has not been tampered with by calculating with a hash function provided in the transmission apparatus 1 and comparing it with the hash value H (Mc) multiplexed in the multi-encrypted content. Based on this, the encrypted content (E (Mav, Ks)) is descrambled and used. For example, the video / audio Mav descrambled by the content receiving device 21 may be output to a display (TV or the like), or the video / audio Mav may be accumulated based on the multiplexed copy control information Mc. it can.

  The reception separation unit 23 receives the multiplexed encrypted content transmitted from the content transmission apparatus 1 on the transmission side, and receives the encrypted content (E (Mav, Ks)), the copy control information Mc, and the first encryption key related information. (E (ECM, Kw)) and the encrypted content (E (Mav, Ks)) and the copy control information Mc are output to the copy control information Mc extraction unit 25 and the first encryption key related information (E (ECM, Kw)) is output to the security module 29. In other words, the reception separation unit 23 filters the received MPEG2 transport stream packet (multi-encrypted content) to generate a video / audio packet (encrypted content (E (Mav, Ks)) and copy control information Mc). And ECM packets (first encryption key related information (E (ECM, Kw))). The reception separation unit 23 corresponds to the reception separation means described in the claims.

  The copy control information Mc extraction unit 25 extracts the copy control information Mc from the encrypted content (E (Mav, Ks)) separated by the reception separation unit 23 and the copy control information Mc, and the hash function calculation unit 27 In addition to outputting to an external storage device (not shown), the encrypted content (E (Mav, Ks)) and copy control information Mc are output to the descrambling unit 37. That is, the copy control information Mc extraction unit 25 outputs the copy control information Mc to the outside, re-encrypts the video / audio Mav with an external storage device or the like, and then re-encrypts based on the copy control information Mc. The video / audio Mav can be handled.

  Further, since the copy control information Mc is stored (included) in the PMT part of the encrypted content (E (Mav, Ks)), it is output to the descrambling part 37 without being separated. An external storage device (not shown) is, for example, D-VHS, and the copy control information Mc extracted by the copy control information Mc extraction unit 25 is stored in the storage via a home network such as IEEE1394. Output to the device.

  When the copy control information Mc is extracted by the copy control information Mc extraction unit 25 and is tampered with illegally, the transmission control unit 35 in the security module 29 stops the transmission of the scramble key Ks, so that it is scrambled. The encrypted content (E (Mav, Ks)) cannot be descrambled. That is, the encrypted content (E (Mav, Ks)) is stored in the content storage unit 41 in a scrambled state based on the copy control information Mc that has been tampered with illegally, so that the video / audio Mav (content) Cannot be used illegally.

  Similarly, when the copy control information Mc is stored in an external storage device (not shown) via a home network such as IEEE 1394, the transmission protection of IEEE 1394 is also based on the copy control information Mc that has been tampered with. Since the encrypted content (E (Mav, Ks)) is transmitted (sent out) by the technology DTCP and protected by the DTCP while being scrambled, the video / audio Mav (content) cannot be illegally used. . In addition, in this embodiment, in the PMT portion of the multiple encrypted content, the copy control information Mc is transmitted in the plain transmission form without being encrypted and transmitted by the existing transmission method. Therefore, the existing content receiving apparatus is not adversely affected.

  The hash function calculation unit 27 calculates the copy control information Mc extracted by the copy control information Mc extraction unit 25 using a hash function, generates a hash value H (Mc), and outputs the hash value H (Mc) to the security module 29. The hash function used in the hash function calculation unit 27 is the same as the hash function provided in the hash function calculation unit 11 of the content transmission apparatus 1 on the transmission side, and the hash calculated by the hash function calculation unit 27 is used. The value H (Mc) corresponds to the comparison function calculation information described in the claims. Hereinafter, the hash value H (Mc) calculated by the hash function calculation unit 27 will be referred to as a comparison hash value H (Mc). This hash function calculation unit 27 corresponds to the calculation means described in the claims.

  The security module 29 is configured by an IC card or the like, and is configured such that information recorded therein cannot be read from the outside, and has tamper resistance (impact resistance). A comparison unit 33 and a transmission control unit 35 are provided.

  The ECM analysis unit 31 stores the first encryption key related information (E (ECM, Kw)) in advance using a work key Kw held in common by the content transmission device 1 on the transmission side and the content reception device 21 on the reception side. The scramble key Ks and the hash value H (Mc) of the copy control information Mc are obtained by decryption, and the scramble key Ks is output to the transmission control unit 35 and the hash value H (Mc) is output to the comparison unit 33. To do. The ECM analysis unit 31 corresponds to the first encryption key related information decryption means described in the claims.

  When the comparison unit 33 compares the hash value H (Mc) acquired by the ECM analysis unit 31 with the comparison hash value H (Mc) calculated by the hash function calculation unit 27, A scramble key Ks transmission permission signal is output to the transmission control unit 35, and if they do not match, a scramble key Ks transmission disable signal is output to the transmission control unit 35. The scramble key Ks transmission permission signal is a signal for permitting output of the scramble key Ks from the transmission control unit 35 to the outside of the security module 29, and the scramble key Ks transmission disable signal is scrambled from the transmission control unit 35 to the outside of the security module 29. This signal disables the output of the key Ks.

  The comparison unit 33 corresponds to the function calculation information comparison means described in the claims, and the scramble key Ks transmission permission signal and the scramble key Ks transmission disabling signal are claimed in the claims. This corresponds to the comparison result described in the section.

  The transmission control unit 35 controls the output of the scramble key Ks input from the ECM analysis unit 31 based on the scramble key Ks transmission permission signal or the scramble key Ks transmission disable signal output from the comparison unit 33. The sending control unit 35 corresponds to the first encryption key sending control means described in the claims.

  The descrambling unit 37 descrambles the encrypted content (E (Mav, Ks)) with the scramble key Ks output from the transmission control unit 35 of the security module 29, and generates an MPEG2 format audio / video content stream (TS). Is to be generated.

  The MPEG2 decoding unit 39 sends the video / audio Mav obtained by decoding the MPEG2 format video / audio content stream (TS) output from the descrambling unit 37 to a display device (not shown) provided outside the content receiving device 21. Is. The descrambling unit 37 and the MPEG2 decoding unit 39 correspond to the content decoding output means described in the claims.

  The content storage unit 41 is configured by a large-capacity hard disk or the like, stores the encrypted content (E (Mav, Ks)) output from the copy control information Mc extraction unit 25, and is descrambled by the descrambling unit 37. The video / audio Mav (content) is stored. However, if the copy control information Mc extracted by the copy control information Mc extraction unit 25 is “copy prohibited”, the descrambled video / audio Mav (content) cannot be accumulated, and a message notifying this fact is not available. (A message such as “Cannot be stored because it is copy-prohibited content!”) Is displayed on the display unit (not shown).

  According to the content receiving device 21, the received demultiplexed content is received by the receiving / separating unit 23 as encrypted content (E (Mav, Ks)) and copy control information Mc, and first encryption key related information (E ( ECM, Kw)). Subsequently, the ECM analysis unit 31 decrypts the first encryption key related information (E (ECM, Kw)) with the work key Kw and includes the first encryption key related information (E (ECM, Kw)). The scramble key Ks and the hash value H (Mc) are acquired. The hash function calculation unit 27 calculates the copy control information Mc with a hash function similar to the hash function provided in the content transmission device 1 on the transmission side, and sets the comparison hash value H (Mc). The comparison unit 33 compares the hash value H (Mc) with the comparison hash value H (Mc). Based on the comparison result, the transmission control unit 35 controls the transmission of the scramble key Ks. Thereafter, the descramble unit 37 decrypts the encrypted content (E (Mav, Ks)) with the scramble key Ks, decodes it with the MPEG2 decoding unit 39, and outputs it as a video / audio Mav (content).

  Therefore, the copy control information Mc is obtained by computing the hash value H (Mc) multiplexed in the multiplex encrypted content and the hash function similar to the hash function provided in the hash function computing unit 11 on the transmission side. The comparison hash value H (Mc) is compared, and based on the comparison result, it can be determined whether the video / audio Mav (content) is available.

  That is, if the comparison result shows that the multiplexed hash value H (Mc) matches the comparison hash value H (Mc) obtained by calculation, the copy control information Mc is not falsified. The use of the video / audio Mav (content) is permitted. If the hash value H (Mc) multiplexed and the hash value H (Mc) calculated on the receiving side do not match, the copy control information Mc has been falsified, and the video / audio Mav (content) Use is not permitted. Accordingly, it is possible to prevent illegal copying of the video / audio Mav (content) or generation of the video / audio Mav (content) including illegal copy control information.

  In this content receiving apparatus 21, the hash function calculation unit 27 calculates the copy control information Mc using a hash function to generate a comparison hash value H (Mc), and the comparison unit 33 calculates the hash value H (Mc). Is compared with the comparison hash value H (Mc). In the content transmitting apparatus 1 on the transmission side, the hash value H (Mc) is not included in the first encryption key related information (EECM, Kw) in advance. The control information Mc may be included, and the comparison unit 33 in the security module 29 may compare the copy control information Mc with each other.

  However, since the copy control information Mc can be assigned to each component such as video, audio, and data, and may be expanded to several tens of bytes, the content transmission device 1 on the transmission side calculates it with a hash function. Thus, when the hash value H (Mc) is generated, the ECM generation unit 7 can generate the data amount of E (ECM, Kw) smaller, and the broadcast transmission band can be used efficiently. In this embodiment, the hash function calculation unit 27 is provided outside the security module 29, but the hash function calculation unit 27 may be provided inside the security module 29.

(Operation of content transmitting apparatus: first embodiment)
Next, the operation of the content transmission apparatus will be described with reference to the flowchart shown in FIG. 3 (see FIG. 1 as appropriate).
First, a video / audio Mav (content) is input to the MPEG2 encoding unit 3 of the content transmitting apparatus 1, and the video / audio Mav (content) is encoded by the MPEG2 encoding unit 3 to generate a video / audio content stream (TS) in the MPEG2 format. And output to the scramble unit 5 (S1).

  Subsequently, the video / audio content stream (TS) is scrambled by the scramble key Ks in the scramble unit 5 to be the encrypted content (E (Mav, Ks)), and is output to the multiplexing unit 13 (S2). Information related to the scramble key Ks is added to the scramble key Ks used in the scramble unit 5 to obtain related information including the scramble key Ks, and the related information including the scramble key Ks is input to the ECM generation unit 7. .

  Further, the copy control information Mc is generated by the copy control information Mc generation unit 9, and is output to the hash function calculation unit 11 and the multiplexing unit 13 (S3). The copy control information Mc is multiplexed into the PMT in the multiplexing unit 13. Then, the hash function calculation unit 11 calculates the copy control information Mc by the hash function provided in the hash function calculation unit 11 and outputs the hash value H (Mc) to the ECM generation unit 7 (S4). .

  Then, the ECM generation unit 7 encrypts the related information including the scramble key Ks and the hash value H (Mc) with the work key Kw, and the first encryption key related information (E (ECM, Kw)) is multiplexed. Is output to the conversion unit 13 (S5). Thereafter, the encrypted content (E (Mav, Ks)), the first encryption key related information (E (ECM, Kw)), and the copy control information Mc (as PMT) are multiplexed by the multiplexing unit 13 and multiplexed encrypted. The content is sent out (S6).

(Operation of Content Receiving Device: First Embodiment)
Next, the operation of the content receiving device 21 will be described with reference to the flowcharts shown in FIGS. 4 and 5 (see FIG. 2 as appropriate). In the description of the operation of the content receiving device 21, the video / audio Mav (() depends on whether or not the copy control information Mc has been tampered with after receiving the multiple encrypted content transmitted from the content transmitting device 1 on the transmitting side. The outline until the (content) is reproduced is described. In the description of the operation of the content receiving device 21, only the information related to decryption or descrambling of the multi-encrypted content is described.

  The multi-encrypted content transmitted from the content transmission device 1 on the transmission side is received by the reception separation unit 23 of the content reception device 21 (S11). Then, the multi-encrypted content is separated by the reception separation unit 23, and the encrypted content (E (Mav, Ks)) and the copy control information Mc are output to the copy control information Mc extraction unit 25, and the first encryption key related Information (E (ECM, Kw)) is output to the ECM analysis unit 31 (S12).

  Then, the copy control information Mc extraction unit 25 extracts the copy control information Mc and outputs it to the hash function calculation unit 27 and an external storage device (not shown), etc., and the encrypted content (E (Mav, Ks)) ) And the copy control information Mc are output to the descrambling unit 37 (S13). Then, the hash function calculation unit 27 calculates the copy control information Mc using the hash function, and generates a comparison hash value H (Mc), which is output to the comparison unit 33 (S14). Further, the ECM analysis unit 31 decrypts the first encryption key related information (E (ECM, Kw)) with the work key Kw, obtains the hash value H (Mc) and the scramble key Ks, and the hash value H (Mc) Is output to the comparison unit 33 and the scramble key Ks is output to the transmission control unit 35 (S15). Reference is now made to FIG.

  Then, the comparison unit 33 compares the hash value H (Mc) with the comparison hash value H (Mc), and determines whether or not they match (S16). That is, in S16, it is determined whether or not the copy control information Mc has been falsified based on the result (comparison result) obtained by comparing the hash value H (Mc) with the comparison hash value H (Mc) in the comparison unit 33. it can. That is, if the comparison results match, it can be determined that the falsification has not occurred, and if they do not match, it can be determined that the falsification has occurred.

  When the comparison unit 33 determines that the hash value H (Mc) and the comparison hash value H (Mc) match (S16, Yes), the comparison unit 33 sends a scramble key Ks transmission permission signal (a permission signal in the figure). ) Is output to the sending control unit 35 (S17). The transmission control unit 35 outputs the scramble key Ks to the descrambling unit 37 based on the scramble key Ks transmission permission signal (S18). The descrambling unit 37 descrambles the encrypted content (E (Mav, Ks)), and an MPEG2 format audio / video content stream (TS) is obtained and output to the MPEG2 decoding unit 39 (S19). The MPEG2 decoding unit 39 decodes the video / audio content stream (TS) in the MPEG2 format and outputs the video / audio Mav (content) (S20).

  If it is determined in S16 that the hash value H (Mc) and the comparison hash value H (Mc) do not match (S16, No), the comparison unit 33 sends a scramble key Ks transmission disable signal (in the figure, (Impossible signal) is output to the transmission control unit 35 (S21), and a message indicating that the encrypted content (E (Mav, Ks)) cannot be reproduced is displayed on the display unit saving illustration (S22).

(Configuration of Content Transmission Device: Embodiment of Reference Example)
FIG. 6 is a block diagram of a content transmission apparatus 1A which is another embodiment (second embodiment) of the content transmission apparatus 1 shown in FIG. 1, and referring to FIG. 6, the content transmission apparatus The configuration of 1A will be described. In addition, the same structure as the structure of the content transmission apparatus 1 attaches | subjects the same code | symbol, and abbreviate | omits the description.

  The content transmission apparatus 1A shown in FIG. 6 includes a markup description language type usage condition information Mml generation unit 51. The markup description language type usage condition information Mml generation unit 51 is XML (extensible Markup Language) or the like. The use condition information Mml which defines the use condition of the contents described in the markup description language is generated. This use condition information Mml includes copy control information Mc. In addition, special playback such as the valid viewing period of the video / audio Mav (content) stored on the receiving side, the number of playbacks, the playback time, fast-forward playback, etc. Detailed control information relating to the use of the video / audio Mav (content), such as whether or not non-linear reproduction (discontinuous reproduction) is possible.

  XML is a general-purpose computer language (markup description language) and can be used in various terminal devices (for example, a content receiving device 21A described later). In addition, when a markup description language is used for the usage condition information Mml of the video / audio Mav (content), the data size (data amount) becomes larger than that described in binary, so unlike the case of the copy control information Mc alone, It is difficult to multiplex to PMT or the like. Therefore, in this embodiment, the use condition information Mml is multiplexed using a DSM-CC data carousel (Digital Storage Media Command and Control).

  According to this content transmitting apparatus 1A, the scramble unit 5 scrambles the video / audio content stream (TS) with the scramble key Ks to obtain the encrypted content (E (Mav, Ks)). Also, the usage condition information Mml generated by the markup description language type usage condition information Mml generation unit 51 is calculated by the hash function calculation unit 11 to generate a hash value H (Mml). Then, the ECM generation unit 7 encrypts the related information including the scramble key Ks and the hash value H (Mml) of the use condition information Mml with the work key Kw, and the first encryption key related information (E (ECM, Kw )). Thereafter, the multiplexing unit 13 multiplexes the encrypted content (E (Mav, Ks)), the first encryption key related information (E (ECM, Kw)), and the use condition information Mml, and performs multiple encryption. Output as content.

  For this reason, on the receiving side, the hash value H (Mml) multiplexed in the multiplex encrypted content and the use condition with the hash function similar to the hash function provided in the hash function calculating unit 11 on the transmitting side on the receiving side If the hash value H (Mml) obtained by calculating the information Mml is compared, and it is further determined whether the encrypted content (E (Mav, Ks)) can be decrypted based on the use condition information Mml Based on the comparison result and the determination result, it can be determined whether the video / audio Mav (content) is available.

  That is, if the comparison result shows that the multiplexed hash value H (Mml) matches the hash value H (Mml) calculated on the receiving side, the copy control information Mc included in the use condition information Mml is falsified. In other words, if it matches the conditions indicated by the use condition information Mml, the use of the video / audio Mav (content) is permitted. If the multiplexed hash value H (Mml) and the hash value H (Mml) calculated on the receiving side do not match, the copy control information Mc included in the use condition information Mml has been falsified. Or if the condition indicated by the use condition information Mml is not met, the use of the video / audio Mav (content) is not permitted. Accordingly, it is possible to prevent illegal copying of the video / audio Mav (content) or generation of the video / audio Mav (content) including illegal copy control information.

(Configuration of content receiving apparatus: embodiment of reference example)
FIG. 7 is a block diagram of a content receiving device 21A which is another embodiment of the content receiving device 21 shown in FIG. 2, and the configuration of the content receiving device 21A will be described with reference to FIG. Note that the same configuration as that of the content receiving device 21 is denoted by the same reference numeral, and the description thereof is omitted.

  The content receiving apparatus 21A illustrated in FIG. 7 includes a usage condition information Mml extraction unit 61 and a usage determination unit 63 in the security module 29A. The usage condition information Mml extraction unit 61 extracts the usage condition information Mml from the DSM-CC data carousel separated by the reception separation unit 23, and uses the usage determination unit 63 of the security module 29A and an external storage device (not shown). Is output.

  The usage determination unit 63 determines each condition included in the usage condition information Mml. When it is determined that each condition is satisfied, a video / audio Mav usage permission signal is output to the transmission control unit 35, and When it is not determined that each condition is satisfied, a video / audio Mav unavailable signal is output to the transmission control unit 35. For example, if the video / audio Mav (content) usage expiration date has passed (exceeded), or if the video / audio Mav (content) playback time has passed (exceeded), the video / audio It is determined that Mav (content) cannot be used (it is not determined that each condition is satisfied), and a video / audio Mav unusable signal is output to the transmission control unit 35.

  According to this content receiving apparatus 21A, the received demultiplexing unit 23 receives the encrypted content (E (Mav, Ks)), the DSM-CC data carousel (use condition information Mml), the first It is separated into one encryption key related information (E (ECM, Kw)). Subsequently, the ECM analysis unit 31 decrypts the first encryption key related information (E (ECM, Kw)) with the work key Kw and includes the first encryption key related information (E (ECM, Kw)). The scramble key Ks and the hash value H (Mml) are acquired. The hash function calculation unit 27 calculates the use condition information Mml with a hash function similar to the hash function provided in the content transmission device 1 on the transmission side, and sets the comparison hash value H (Mml). The comparison unit 33 compares the hash value H (Mml) with the comparison hash value H (Mml). Further, the usage determining unit 63 determines whether each condition of the usage condition information Mml is satisfied. Based on these comparison results and determination results, the transmission control unit 35 controls transmission of the scramble key Ks. After that, the descramble unit 37 decrypts the encrypted content (E (Mav, Ks)) with the scramble key, decodes it with the MPEG2 decoding unit 39, and outputs it as video / audio Mav (content).

  Therefore, the usage condition information Mml is obtained by computing the hash value H (Mml) multiplexed in the multiplex encrypted content and the hash function similar to the hash function provided in the hash function computing unit 11 on the transmission side. The comparison hash value H (Mml) is compared, and based on this comparison result and the determination result of the usage determining unit 63, it can be determined whether the video / audio Mav (content) is available.

  That is, when the comparison result shows that the multiplexed hash value H (Mml) matches the comparison hash value H (Mml) obtained by calculation, the use condition information Mml is not falsified. The use of the video / audio Mav (content) is permitted. If the multiplexed hash value H (Mml) and the hash value H (Mml) calculated on the receiving side do not match, the use condition information Mml has been falsified, and the video / audio Mav (content) Use is not permitted. Further, it is determined whether or not the video / audio Mav (content) is usable based on the determination result of the usage condition information Mml by the usage determination unit 63.

  Accordingly, it is possible to prevent illegal copying of the video / audio Mav (content) or generation of the video / audio Mav (content) including illegal copy control information. Further, by setting the usage condition information Mml according to the intention of the producer (broadcaster) of the video / audio Mav (content) on the transmission side, the video / audio Mav (based on the usage condition information Mml ( Use (reproduction) of (content) can be realized.

(Operation of Content Transmission Device: Embodiment of Reference Example)
Next, the operation of the content transmitting apparatus 1A shown in FIG. 6 will be described with reference to the flowchart shown in FIG.
First, a video / audio Mav (content) is input to the MPEG2 encoding unit 3 of the content transmitting apparatus 1A, and the video / audio Mav (content) is encoded by the MPEG2 encoding unit 3 to generate a video / audio content stream (TS) in the MPEG2 format. And output to the scramble unit 5 (S31).

  Subsequently, the video / audio content stream (TS) is scrambled by the scramble key Ks in the scramble unit 5 to be the encrypted content (E (Mav, Ks)), and is output to the multiplexing unit 13 (S32). Information related to the scramble key Ks is added to the scramble key Ks used in the scramble unit 5 to obtain related information including the scramble key Ks, and the related information including the scramble key Ks is input to the ECM generation unit 7. .

  Further, the use condition information Mml is generated by the markup description language type use condition information Mml generating unit 51, and this use condition information Mml is output to the hash function calculating unit 11 and also output to the multiplexing unit 13 (S33). ). The usage condition information Mml includes conditions set according to the intentions of the content creator and broadcaster who are the owners (or users and users) of the content transmitting apparatus 1A, and incorporates these conditions. It is generated by the markup description language type usage condition information Mml generation unit 51.

  Then, the usage condition information Mml is calculated by the hash function provided in the hash function calculation unit 11 in the hash function calculation unit 11, and is converted into a hash value H (Mml) and output to the ECM generation unit 7 (S34). .

  Then, the ECM generation unit 7 encrypts the related information including the scramble key Ks and the hash value H (Mml) with the work key Kw, and the first encryption key related information (E (ECM, Kw)) is multiplexed. Is output to the conversion unit 13 (S35). Thereafter, the multiplex unit 13 multiplexes the encrypted content (E (Mav, Ks)), the first encryption key related information (E (ECM, Kw)), and the use condition information Mml to obtain the multiplex encrypted content. Are sent out (S36).

(Operation of content receiving apparatus: embodiment of reference example)
Next, the operation of the content reception device 21A shown in FIG. 7 will be described with reference to the flowcharts shown in FIGS. In the description of the operation of the content receiving device 21A, the video / audio Mav (() depends on whether or not the usage condition information Mml has been tampered with after receiving the multiple encrypted content transmitted from the content transmitting device 1A on the transmitting side. The outline until the (content) is reproduced is described. In the description of the operation of the content receiving device 21A, only the information related to decryption or descrambling of the multi-encrypted content is described.

  The multi-encrypted content transmitted from the content transmission device 1A on the transmission side is received by the reception separation unit 23 of the content reception device 21A (S41). Then, the multi-encrypted content is separated by the reception separating unit 23, the encrypted content (E (Mav, Ks)) is extracted to the descrambling unit 37, and the DSM-CC data carousel (usage condition information Mml) is extracted to the use condition information Mml. The first encryption key related information (E (ECM, Kw)) is output to the unit 61 to the ECM analysis unit 31 (S42).

  Then, the usage condition information Mml extraction unit 61 extracts the usage condition information Mml, and outputs it to the hash function calculation unit 27, the usage determination unit 63, an external storage device (not shown), and the like (S43). Then, the usage condition information Mml is calculated by the hash function in the hash function calculation unit 27, and the comparison hash value H (Mml) is generated and output to the comparison unit 33 (S44). Further, the ECM analysis unit 31 decrypts the first encryption key related information (E (ECM, Kw)) with the work key Kw, acquires the hash value H (Mml) and the scramble key Ks, and the hash value H (Mml) Is output to the comparison unit 33 and the scramble key Ks is output to the transmission control unit 35 (S45). Reference is now made to FIG.

  Then, the usage determining unit 63 determines whether or not the encrypted content (E (Mav, Ks)), that is, the video / audio Mav can be used (whether each condition is satisfied) (S46). When the usage determining unit 63 determines that the encrypted content (E (Mav, Ks)), that is, the video / audio Mav can be used (S46, Yes), the video / audio Mav usage permission signal (FIG. Medium permission signal) is output to the transmission control unit 35 (S47).

  Further, the comparison unit 33 compares the hash value H (Mml) with the comparison hash value H (Mml), and determines whether or not they match (S48). That is, in S48, it is determined whether or not the use condition information Mml has been falsified based on the result (comparison result) obtained by comparing the hash value H (Mml) with the comparison hash value H (Mml) in the comparison unit 33. it can. That is, if the comparison results match, it can be determined that the falsification has not occurred, and if they do not match, it can be determined that the falsification has occurred.

  When the comparison unit 33 determines that the hash value H (Mml) and the comparison hash value H (Mml) match (S48, Yes), the comparison unit 33 sends a scramble key Ks transmission permission signal (a permission signal in the figure). ) Is output to the sending control unit 35 (S49). The transmission control unit 35 outputs the scramble key Ks to the descrambling unit 37 based on the scramble key Ks transmission permission signal (S50). The descramble unit 37 descrambles the encrypted content (E (Mav, Ks)) to obtain an MPEG2 format audio / video content stream (TS), which is output to the MPEG2 decode unit 39 (S51). The MPEG2 decoding unit 39 decodes the video / audio content stream (TS) in the MPEG2 format and outputs the video / audio Mav (content) (S52).

  In S46, when it is not determined by the usage determining unit 63 that the encrypted content (E (Mav, Ks)), that is, the video / audio Mav is available (S46, No), the usage determining unit 63 uses the video / audio Mav. A disabled signal (disabled signal in the figure) is output to the sending control unit 35 (S53). A message indicating that the encrypted content (E (Mav, Ks)), that is, the video / audio Mav cannot be reproduced (according to the use condition information Mml) is displayed on the display unit saving illustration (S54).

  In S48, if the comparison unit 33 determines that the hash value H (Mml) does not match the comparison hash value H (Mml) (S48, No), the comparison unit 33 sends a scramble key Ks transmission disable signal. (No signal in the figure) is output to the transmission control unit 35 (S55), and a message indicating that the encrypted content (E (Mav, Ks)), that is, the video / audio Mav cannot be reproduced, is displayed on the display unit saving the illustration. (S56).

(About the digital copy control descriptor)
Finally, the digital control descriptor will be described. FIG. 11 is a diagram showing a specific example of the digital copy control descriptor (data table). As shown in FIG. 11, the digital copy control descriptor describes the information for controlling the copy generation in the digital recording device and the maximum transmission rate, and the 8-bit “descriptor” from the top (left side in the figure). Tag, 8-bit “descriptor length”, 2-bit “digital copy control information”, 1-bit “maximum transmission rate flag”, 1-bit “component control flag”, 2-bit “copy control type”, and 2-bit “APS control” Data ".

  The “descriptor tag” indicates the beginning of the digital copy control descriptor and identifies the descriptor. “Descriptor length” indicates the length (area) of the descriptor.

  “Digital copy control information” is information for controlling copying (copying) of digital content, and is divided into “copy not possible”, “copy one generation”, “copy free”, and the like. The “maximum transmission rate flag” is a flag for identifying the maximum transmission rate.

  The “component control flag” is 1 when copy control information is assigned to each component (video, audio, data, etc.). In this case, the copy control information is described for each component. “APS control data” is information for controlling APS (Analog Protection System).

  As mentioned above, although this invention was demonstrated based on one Embodiment, this invention is not limited to this.

  For example, the processing of each component of the content transmission device 1 and the content reception device 21 can be regarded as a content transmission program and a content reception program described in a general-purpose computer language.

  In these cases, the same effects as those of the content transmitting device 1 and the content receiving device 21 can be obtained. In the case of a content transmission program and a content reception program, these programs can be recorded on a recording medium or the like and distributed.

DESCRIPTION OF SYMBOLS 1, 1A content transmission apparatus 3 MPEG2 encoding part 5 Scramble part 7 ECM production | generation part 9 Copy control information Mc production | generation part 11, 27 Hash function calculating part 13 Multiplexing part 21, 21A Content reception apparatus 23 Reception separation part 25 Copy control information Mc Extraction unit 29, 29A Security module 31 ECM analysis unit 33 Comparison unit 35 Transmission control unit 37 Descramble unit 39 MPEG2 decoding unit 41 Content storage unit

Claims (2)

A digital broadcasting system including a content transmitting device and a content receiving device that transmit and receive content indicating video and audio,
The content transmission device includes:
A content encryption means for encrypting a video / audio content stream in a stream format with the first encryption key to obtain encrypted content;
For tampering detection in which plaintext copy control information, which is information for controlling the number of times the content provider provides the content is copied on the receiving side that receives the content, is shortened to a fixed size value Copy control information processing means for processing into function calculation information calculated by a function that generates a code of
The ECM used when reproducing the video and the audio on the receiving side by encrypting the related information and the function calculation information including the first encryption key and identifying the operator with the second encryption key Encryption key encryption means;
Multiple sending means for sending multiple encrypted content obtained by multiplexing the ECM packet of the ECM to the video / audio packet of the encrypted content in a transport stream format in which the plaintext copy control information is multiplexed in the PMT portion; ,
With
The content receiving device is:
The video stream of the encrypted content multiplexed in the multiplexed encrypted content, the plaintext copy control information included in the PMT, and the ECM packet of the ECM are received. Receiving separation means for separating
The ECM separated by the reception separating means is decrypted with a second encryption key similar to the second encryption key provided in the content transmission device, and the first encryption key and function operation information included in the ECM A first encryption key related information decryption means for obtaining
The plaintext copy control information is extracted from the video / audio packet of the encrypted content separated by the reception separation means and the plaintext copy control information included in the PMT, and the encrypted content and the copy control information are decrypted. A copy control information extracting means for outputting to the content output means and outputting the copy control information to the content storage means and the outside;
An arithmetic means for calculating the extracted plaintext copy control information with a function similar to a function for generating a code for detecting falsification provided in the content transmission device, and setting it as comparison function calculation information;
The function calculation information acquired by the first encryption key related information decryption means is compared with the comparison function calculation information calculated by the calculation means. If they match, the copy control information extracted from the PMT is A function operation information comparison unit that outputs a transmission permission signal indicating that the message has not been tampered with as a comparison result, and outputs a transmission disable signal that indicates that the message has not been tampered with as a comparison result.
When the transmission permission signal is input from the function calculation information comparison unit, the first encryption key is transmitted. On the other hand, when the transmission disable signal is input, the first encryption key is stopped from being transmitted. Encryption key transmission control means;
Accepting the input of the encrypted content and copy control information output from the copy control information extracting means, decrypting and outputting the encrypted content with the first encryption key sent by the first encryption key sending control means And a content decryption output means for performing copy control based on the received copy control information when copying the decrypted content or the encrypted content to an external storage device;
When the decrypted content or the encrypted content output from the content decryption output unit is stored therein, and the copy control information extracted by the copy control information extraction unit indicates copy prohibition Does not store, a content storage unit that stores according to the copy control information when the extracted copy control information indicates copy permission or the number of copies;
A digital broadcasting system comprising: For detecting falsification that includes a first encryption key for encrypting content indicating video and audio and that can identify the provider providing the content, and shortening the information to a fixed size value The function calculation information obtained by calculating and processing the plaintext copy control information, which is information for controlling the number of times the content is copied by a function for generating a code, is encrypted with a second encryption key and A copy of the plaintext in the PMT portion of the multiplexed encrypted content obtained by multiplexing the ECM packet of the ECM used when reproducing video and audio with the video and audio packet of the encrypted content encrypted with the first encryption key. A content receiving device that receives control information in a multiplexed transport stream format,
The video stream of the encrypted content multiplexed in the multiplexed encrypted content, the plaintext copy control information included in the PMT, and the ECM packet of the ECM are received. Receiving separation means for separating
The ECM separated by the reception separating means is decrypted with a second encryption key similar to the second encryption key provided on the transmission side, and the first encryption key and function calculation information included in the ECM are obtained. First encryption key related information decryption means
The plaintext copy control information is extracted from the video / audio packet of the encrypted content separated by the reception separation means and the plaintext copy control information included in the PMT, and the encrypted content and the copy control information are decrypted. A copy control information extracting means for outputting to the content output means and outputting the copy control information to the content storage means and the outside;
The extracted plaintext copy control information is calculated by a function similar to a function that generates a code for detection of alteration provided in the transmission side, and is set as comparison function calculation information;
The function calculation information acquired by the first encryption key related information decryption means is compared with the comparison function calculation information calculated by the calculation means. If they match, the copy control information extracted from the PMT is A function operation information comparison unit that outputs a transmission permission signal indicating that the message has not been tampered with as a comparison result, and outputs a transmission disable signal that indicates that the message has not been tampered with as a comparison result.
When the transmission permission signal is input from the function calculation information comparison unit, the first encryption key is transmitted. On the other hand, when the transmission disable signal is input, the first encryption key is stopped from being transmitted. Encryption key transmission control means;
Accepting the input of the encrypted content and copy control information output from the copy control information extracting means, decrypting and outputting the encrypted content with the first encryption key sent by the first encryption key sending control means And a content decryption output means for performing copy control based on the received copy control information when copying the decrypted content or the encrypted content to an external storage device;
When the decrypted content or the encrypted content output from the content decryption output unit is stored therein, and the copy control information extracted by the copy control information extraction unit indicates copy prohibition Does not store, a content storage unit that stores according to the copy control information when the extracted copy control information indicates copy permission or the number of copies;
A content receiving apparatus comprising:

Images