JP2005006347A - Device and method for decoding and reproducing confidential information - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable confidential information which only those who have watched video/audio information can know to be delivered prior to the transmission of the video/audio information. <P>SOLUTION: A broadcasting station broadcasts, prior to the start of a TV program, encrypted confidential data to be decoded interlinking with the program together with program-identifying information for specifying the data. A receiver receives the confidential data and stores them in a confidential information storage part 6. The broadcasting station transmits a decoding key which can decode the confidential data along the progress of the program. If a viewer watches the program, the receiver receives the decoding key and decodes the secret data stored in the confidential information storage part 6 at a confidential information decoding part 9 using the decoding key. The decoded confidential data are processed at a confidential information reproducing part 10 and displayed together with TV images. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an apparatus and method for receiving and reproducing video information or audio information transmitted from a transmission source and decoding and reproducing encrypted confidential information associated with the video information or audio information.

  The conventional Internet is often used in a usage form in which a user actively retrieves information desired by the user. This usage form is called “PULL type”. On the other hand, the Internet is increasingly used in a “PUSH type” usage mode in which data is sent from the broadcast station to the user one after another, rather than the user actively collecting information. It was. Data sent by the PUSH type service is displayed one after another on the user's personal computer display screen.

  However, when using the Internet at home, the telephone line is often connected to an Internet provider. Therefore, in order to receive the PUSH type data sent from the broadcasting station as needed, it is necessary to keep the telephone call to the Internet provider at all times, and there is a problem that the telephone bill becomes very expensive.

  On the other hand, “Web cast” (Internet: ASCII, Vol. 2) broadcasts Internet data in HTML (Hyper Text Makeup Language) format using the vertical blanking period (VBI) of the terrestrial television broadcast signal. No. 5, pp. 166-167, May 1997). In Japan, since April 1996, four lines during the vertical blanking period of 21 lines of terrestrial television broadcast signals have been allocated as data multiplex broadcasts, and Webcasting has been carried out using these four line transmission paths.

  Also in satellite digital television broadcasting, attempts have been started to superimpose Internet data in HTML format on digitized video information and audio information. In the case of digital television broadcasting, video information, audio information, and data can be handled as digital information in a unified manner, so that Internet data can be broadcast on television waves without using the vertical blanking interval.

  And, when receiving Internet data that is broadcast superimposed on terrestrial TV broadcasting or satellite digital TV broadcasting, it is not necessary to use a telephone line. There is an advantage that it can always be received inexpensively.

  Further, when data is superimposed on a television broadcast, there is an advantage that the television image and the data can be delivered to the user in conjunction with each other. As a result, data related to TV programs can be distributed. For example, data such as educational texts can be distributed at the same time as video for educational programs and displayed on a TV screen or PC screen in multiple windows. Is possible. Also, by broadcasting new data every time the content or topic of the television broadcast changes, the data content can be changed following the content or topic.

  In addition, when using the receiver of the Bitcast / VBI service (source: Nikkei Multimedia, pp. 52-59, April 1997 issue) scheduled to start broadcasting in Japan, it was transmitted by television broadcasting. Internet data can be temporarily stored in a storage device of a receiver, and the stored Internet data can be displayed in conjunction with a broadcast program. That is, data linked with a TV program or TV commercial can be broadcast in advance by data broadcasting, and displayed on the screen at the moment when the TV program or TV commercial starts.

  In Patent Document 1 (Japanese Patent Laid-Open No. 9-139933), as a method for accessing a database holding confidential data, a broadcasting station broadcasts guidance information for database access superimposed on a television image, and broadcasts it. The viewer shows a method of obtaining confidential data by inputting the received guide information for accessing the database and a password known by the viewer and accessing the database through a telephone line.

The prior art documents listed above are as follows.
JP-A-9-139933

  By the way, some web pages (Internet data) cannot be viewed by people other than those authorized by the information provider. Generally, a password is set for these secret Web pages, and only a person who knows the password can access the secret Web page.

  In this way, when using the Internet in a “PULL type” usage mode in which the user actively takes the information he / she wants, the information provider sets a password on the Web page to be kept secret. A Web page allowing only access from an appropriate user can be published on the Internet.

  Therefore, it is very convenient if a Web page that is allowed to be accessed only by a viewer permitted by the information provider can be broadcasted or published for a Web page that should be displayed in conjunction with a TV image. For example, a secret Web page is broadcast prior to the start time of the TV program, and only a viewer permitted by the information provider can read and view the secret Web page as the TV program progresses. That's it.

  However, when data is distributed by the PUSH type service like the above-mentioned Bitcast / VBI service, the data stored in the storage device of the receiver can be viewed by anyone at any time. There is a problem that it is not possible to distribute a Web page that allows only access from the Internet prior to the broadcast time of the TV program.

  As a method of solving this problem using a known encryption technique, a broadcast station encrypts and broadcasts data related to a television program, and the receiver receives the encrypted data and stores it in a storage device. Then, a method is conceivable in which the viewer decrypts the stored encrypted data separately using a decryption key (password or the like) sent from the broadcasting station by e-mail or postcard.

  For example, if a broadcast program name that can use the decryption key is written in addition to the decryption key in an e-mail or postcard sent from the broadcast station, the viewer who has obtained the decryption key Only the encrypted data related to the broadcast program specified by can be decrypted.

  However, in the case of this method, in order to reproduce the confidential data to be reproduced in conjunction with the television program, the viewer selects the television program from among the encrypted data stored in the storage device of the receiver. It is necessary to retrieve related encrypted data, and to decrypt the retrieved encrypted data with a decryption key sent from a broadcasting station by e-mail or mail. There is a problem that you cannot concentrate on the program.

  Moreover, even within the same TV program, there are cases where it is desired to dynamically change the person who can view the confidential data according to the progress of the program or the content of the confidential data. There is also a problem that it is extremely difficult to send the decryption key in advance by e-mail or mail.

  In addition, when decrypting encrypted data using a decryption key sent from a broadcasting station by e-mail or mail, the viewer can download the encrypted data at any time after the point when the decryption key is obtained. Because it can be decrypted, it is impossible to perform access control with a time limit, such as preventing confidential data to be played back in conjunction with the TV program from being viewed at a timing before the start of the TV program broadcast. There is a problem.

  In addition, as described above, Patent Document 1 (Japanese Patent Laid-Open No. 9-139933) discloses a method in which a broadcasting station provides guidance information for accessing a database as a method for accessing a database holding confidential data. The viewer obtains confidential data by inputting the received guidance information for accessing the database and a password known by the viewer and accessing the database through a telephone line. The method is shown.

  However, this method has a problem that a communication cost is required because it is necessary to use a telephone line. Further, since it is necessary to provide a communication device for connecting to a telephone line, there is a problem that the television receiving system becomes complicated. Further, in this case, the password to be entered by the viewer needs to be obtained separately by e-mail or mail, which is troublesome as described above.

  By the way, as a way to get viewers to watch TV commercials, there are cases where a present from the sponsor is sent only to the viewers who have watched the TV program provided by the sponsor. By providing useful information and special rights only to viewers, more viewers can watch TV commercials broadcast by the sponsor.

  For example, if a computer program that operates in conjunction with a TV program is broadcast in advance and only the viewer who has watched the TV program can be given the right to execute the computer program, then the computer program will be executed. This is very useful as a way for viewers to watch TV commercials because viewers watch TV programs.

  However, as described above, when data is distributed by the PUSH type service, since the data stored in the storage device of the receiver can be viewed by anyone at any time, only the viewer who has watched the TV program. There is a problem that it is impossible to distribute a Web page that permits access to the Internet prior to the broadcast time of the TV program.

  In the satellite digital television broadcast “PerfecTV!” That has started broadcasting in Japan, a scrambled video and a decryption key for decrypting the scrambled video are broadcast simultaneously. However, data and programs used in a television program cannot be distributed to viewers in advance prior to the broadcast time of the television program.

  That is, PerfecTV! In this case, even when there is a large amount of confidential data to be decoded in conjunction with the television program, it is necessary to broadcast the confidential data at the timing of using the confidential data. Furthermore, even when the same confidential data is used in a plurality of scenes or programs, there is a problem that the broadcast station must broadcast the confidential data every time the confidential data is used.

  In addition, PerfecTV! In this case, since the scrambled video and the decryption key for decrypting the scrambled video are distributed at the same time, the confidential data provided to the viewer by media other than broadcasting such as CDROM is stored. However, there is a problem that it cannot be decoded and reproduced in conjunction with a TV program.

  In view of the above, the present invention (1) prior to transmission of video / audio information, secret information that can be known only by a person who has viewed video / audio information, which is video information or audio information such as a television or radio program. (2) Even when confidential information related to video / audio information is distributed to an unspecified number of viewers, only a specific viewer can be given the right to know the information. 3) According to the progress of the video / audio information, the information can be disclosed / not disclosed, or the viewer who can know the information can be dynamically changed. (4) The viewer can decrypt the confidential information. (5) When the same confidential information is used in a plurality of scenes or video / audio information, the confidential information once distributed is reused. (6) C Even confidential information provided to viewers by the media, such as ROM, a play is decoded in conjunction to audiovisual information, as an object to the.

The secret information decoding / reproducing apparatus of the present invention comprises:
Confidential information storage means for storing encrypted information as confidential information;
Video / audio information receiving means for receiving video / audio information which is video information or audio information transmitted from a transmission source;
Video / audio information reproducing means for reproducing the video / audio information received by the video / audio information receiving means;
Data detection means for detecting data superimposed on the video and audio information;
Based on information included in the data detected by the data detection means, confidential information specifying means for specifying the confidential information to be decoded out of the confidential information stored in the confidential information storage means,
A decryption key extracting means for extracting a decryption key for decrypting the confidential information specified by the confidential information specifying means from information included in the data detected by the data detecting means;
Of the confidential information stored in the confidential information storage means, the confidential information decrypting means for decrypting the confidential information specified by the confidential information specifying means with the decryption key extracted by the decryption key extracting means When,
Confidential information reproducing means for reproducing the confidential information decoded by the confidential information decoding means;
Shall be provided.

  In this case, the confidential information stored in the confidential information storage means is the video / audio information at a time before the time when the decryption key for decrypting the confidential information is extracted by the decryption key extraction means. It is assumed that the data is detected by the data detection means.

  Alternatively, the confidential information storage means may be an external storage device in which encrypted information is written as confidential information.

  In the claims and the specification, not only the encrypted information but also information obtained by decrypting the encrypted information is referred to as confidential information for convenience.

  In the confidential information decoding / playback device of the present invention configured as described above, the transmission source transmits the confidential information to be decoded in advance in conjunction with the video / audio information before transmitting the video / audio information. Before transmission of the video / audio information, the confidential information to be decoded in conjunction with the video / audio information is stored in the confidential information storage means. Alternatively, the transmission source distributes to the viewer an external storage device such as a CDROM in which confidential information to be decoded is written in advance in conjunction with the video / audio information in advance of transmission of the video / audio information. The secret information storage means stores the secret information to be decoded in conjunction with the video / audio information before transmitting the video / audio information.

  In a state where the confidential information is stored in the confidential information storage means in this manner, the transmission source can specify the confidential information related to this together with the video / audio information, information such as identification information of the video / audio information, and By transmitting a decryption key for decrypting the confidential information specified by this, in the confidential information decoding and reproducing device, the confidential information stored in the confidential information storage means by the confidential information specifying means, Confidential information to be decrypted is identified, a decryption key for decrypting the identified confidential information is extracted by the decryption key extracting means, and the identified confidential information is decrypted by the confidential information decrypting means. However, it is decrypted with the extracted decryption key, and the decrypted confidential information is reproduced by the confidential information reproducing means.

  Therefore, the confidential information that can be known only by the person who has viewed the video / audio information can be distributed in advance prior to the transmission of the video / audio information, and the viewer is not forced to decode the confidential information. When the same confidential information is used in a plurality of scenes or video / audio information, the confidential information distributed once can be reused and can be used by a medium such as a CDROM. Even the secret information provided to the viewer can be decoded and reproduced in conjunction with the video / audio information.

  Furthermore, by adjusting the transmission and content of the decryption key at the transmission source, the information can be disclosed / hidden or the viewer who can know the information is dynamically changed according to the progress of the video / audio information. In addition, even when confidential information related to video / audio information is distributed to an unspecified number of viewers, only a specific viewer can be given the right to know the information.

  As described above, according to the present invention, the confidential information that can be known only by the person who has viewed the video / audio information can be distributed in advance prior to the transmission of the video / audio information, and the viewer can decrypt the confidential information. If the same confidential information is used for multiple scenes or video / audio information, the confidential information once distributed must be reused. In addition, confidential information provided to the viewer by a medium such as a CDROM can be decoded and reproduced in conjunction with the video / audio information.

  Furthermore, according to the progress of the video / audio information, the information can be disclosed / hidden, or the viewers who can know the information can be changed dynamically, and the confidential information related to the video / audio information can be unspecified. Even when distributed to other viewers, only a specific viewer can be given the right to know information.

  The embodiment of the present invention will be described in the case where the present invention is applied to a television broadcast transmission / reception system. However, as will be described later, the present invention can also be applied to a radio broadcast transmission / reception system.

  In the “Claims” and “Means for Solving the Problems” in the specification, “video information or audio information” is defined as “video audio information”. However, the following embodiments describe the present invention. Since the present invention is applied to a television broadcast transmission / reception system, in the following embodiments, “video / audio information” means “video information and audio information”.

[First Embodiment]
In the first embodiment, the broadcasting station broadcasts the confidential data in advance by television broadcasting prior to the start of the television program, and decodes the confidential data broadcast earlier in accordance with the progress of the television program. Broadcast the key. In a receiving system including a television receiver, secret data broadcast earlier is stored in a secret information storage unit, a decryption key broadcast in accordance with the progress of the TV program is detected, and the secret information is detected using this decryption key. The secret data stored in the storage unit is decoded and displayed or reproduced as an image or sound.

  However, in the following, only the case where the confidential data is displayed as an image will be shown.

  In the first embodiment, the present invention is applied to a transmission / reception system for terrestrial television broadcasting.

(Constitution)
FIG. 1 shows an example of a transmission / reception system according to the first embodiment. The television broadcast station 30 transmits a modulated analog video / audio signal as a terrestrial television broadcast by a television broadcast radio wave 31 and, for example, the tenth to thirteenth lines during the vertical blanking period of the television video signal. Digital data such as secret data and a decryption key is transmitted using the four lines up to. Since there is a transmission capacity of 9.6 kbps per line, 38.4 kbps data can be transmitted over four lines.

  In the case of this example, the transmitted digital data is Internet data in HTML format, and the confidential data is encrypted. Typical Internet data includes layout information, plain text, moving images, still images, audio, link information to other Internet data, or computer programs.

  The reception system as a whole includes a television receiver 40, a television antenna 41, a storage device unit 44, a television operation remote controller 50, and a printer 60, and a modulated analog video / audio signal and secret data from the television broadcast station 30. A television broadcast signal including digital data such as a decryption key is received by the television antenna 41 and is tuned by a tuning unit in the television receiver 40.

  The television receiver 40 can simultaneously display the television image 42 and the data image 43 based on the Internet data on the display screen, and normally displays the television image 42 on the entire display screen, but receives the confidential data. When storing the secret data stored in the secret information storage unit, and then receiving the decryption key for decrypting the secret data and decrypting the secret data stored in the secret information storage unit with the decryption key, A data image 43 based on the decrypted Internet data is displayed simultaneously with the television video 42.

  As a method of simultaneously displaying the television image 42 and the data image 43, in addition to the method of dividing the display screen into two in the horizontal direction as shown in the figure, the so-called picture-in-picture method or the method of displaying the television image 42 on the entire display screen. In addition, a method of displaying the data image 43 by being distributed over a plurality of areas on the television video 42 in a manner that overlaps with it can be used. Further, the data image 43 may be displayed on a display device different from the display unit of the television receiver 40.

  The storage device unit 44 constitutes the above-described secret information storage unit and a decryption key storage unit described later, and uses a hard disk (magnetic disk), a magneto-optical disk, a flash memory, or the like as a storage medium, and a USB (Universal Serial). Bus) 47 connects to the television receiver 40. Thus, data can be transferred between the television receiver 40 and the storage device unit 44 at 12 Mbps.

  However, the storage device unit 44 may be installed in the television receiver 40. Further, if an exchangeable recording medium such as an MD, ZIP disk, or PCMPCIA compatible flash memory card is used as the storage medium of the storage unit 44, the storage capacity can be easily increased.

  The TV operation remote controller 50 transmits an infrared remote control signal to the infrared receiver 45 of the TV receiver 40 to control the TV receiver 40. The TV operation remote controller 50 includes a data selection dial 51, a data print key 53, a data erase key 54, and The other key group 59 is provided. The other key group 59 includes a power switch, a channel selection key, a volume adjustment key, and the like provided in a normal television operation remote controller.

  By rotating the data selection dial 51, the secret data to be redisplayed is selected from the secret data stored in the secret information storage unit of the storage unit 44. As will be described later, the selected secret data is decrypted by a decryption key stored in the decryption key storage unit of the storage device unit 44 for decrypting the selected secret data, The data image 43 is displayed again.

  The data print key 53 is pressed when the secret data is displayed after being decrypted by the decryption key or when the secret data to be redisplayed is selected and redisplayed by the data selection dial 51. Thus, the secret data displayed or reproduced is printed as an image on the paper 61 by the printer 60.

  In this case, the decrypted confidential data is converted into an infrared signal by the infrared transmission unit 46 of the television receiver 40 and transmitted to the printer 60. This infrared transmission conforms to the IrDA 1.1 standard and can transfer print data at 4 Mbps.

  The data erasure key 54 is for erasing the confidential data stored in the confidential information storage unit of the storage device unit 44, as described later, when pressed.

  FIG. 2 shows a functional block configuration of the secret information decoding / playback apparatus of the first embodiment. The secret information decoding / playback apparatus of this embodiment includes a channel selection unit 1, an analog demodulation unit 2, a video / audio / data output unit 3, and a data processing unit 15.

  A modulated analog video / audio signal and a television broadcast signal including digital data such as secret data and a decryption key are selected by the channel selection unit 1, and the modulated analog video / audio in the selected TV broadcast signal is selected. The signal is demodulated by the analog demodulator 2, and the demodulated analog video / audio signal is supplied to the video / audio / data output unit 3. The video / audio / data output unit 3 includes the display unit and the speaker of the television receiver 40 shown in FIG. 1, and the TV video and the data image are displayed on the display screen of the display unit, and the TV audio is reproduced from the speaker. The

  The data processing unit 15 is connected to the system bus 4 by a data detection unit 5, a secret information storage unit 6, a secret information identification unit 7, a decryption key extraction unit 8, a secret information decryption unit 9, a secret information reproduction unit 10, The decryption key storage unit 11, the confidential information erasing unit 12, the print processing unit 13, and the control unit 14 are connected to each other.

  However, the data processing unit 15 can be configured such that one block includes several functional parts, or one functional part is divided into several blocks in terms of implementation.

  The data detection unit 5 detects digital data such as secret data and a decryption key in the television broadcast signal selected by the channel selection unit 1 and outputs the digital data to the system bus 4.

  The secret information storage unit 6 stores secret data included in the data detected by the data detection unit 5 and is provided in the storage device unit 44 as described above.

  The secret information specifying unit 7 is based on information such as broadcast program identification information, which will be described later, included in the data detected by the data detection unit 5, and is a television image of the secret data stored in the secret information storage unit 6. And the secret data which should be decoded as audio | voice is reproduced | regenerated is specified.

  The decryption key extraction unit 8 extracts a decryption key for decrypting the secret data specified by the secret information specifying unit 7 from the information included in the data detected by the data detection unit 5.

  The secret information decryption unit 9 uses the decryption key extracted by the decryption key extraction unit 8 for the secret data specified by the secret information identification unit 7 out of the secret data stored in the secret information storage unit 6. Decrypt.

  The secret information reproducing unit 10 processes the secret data decoded by the secret information decoding unit 9, that is, the Internet data in the HTML format in this example so as to be displayed, and outputs it to the video / audio / data output unit 3. Output.

  The decryption key storage unit 11 stores the decryption key extracted by the decryption key extraction unit 8 and is provided in the storage device unit 44 as described above.

  The secret information erasure unit 12 erases the secret data from the secret information storage unit 6 as described later when the data erase key 54 of the television operation remote controller 50 is pressed.

  When the data print key 53 of the television operation remote controller 50 is pressed, the print processing unit 13 processes the confidential data to be printed by the printer 60 as described later, and outputs the confidential data to the infrared transmission unit 46.

  The control unit 14 controls processing of the entire secret information decoding / playback apparatus. An error correction unit that corrects a data transmission error is connected to the system bus 4 as necessary.

(Operation when receiving and storing confidential data)
In the first embodiment, first, the television broadcast station 30 encrypts data to be linked to the television program as confidential data at a time before the start time of the television program, and performs a vertical blanking of the television video signal. Broadcast using the elimination period.

  For example, IDEA (International Data Encryption Algorithm) is used as the encryption method in this case. IDEA is an encryption method developed at the Swiss Federal Institute of Technology, and is a shared key encryption method in which an encryption key for encrypting information and a decryption key for decrypting this encryption are the same key ( Or a secret key cryptosystem). The bit length of the key is set to 128. The IDEA encryption method is also used in cipher mail software PGP (Pretty Good Privacy). IDEA with a 128-bit key is currently a mainstream DES (the key is 56 bits long), Triple DES (the key is 112 bits long) ) Is said to be safer.

  As an encryption method for encrypting data, besides the shared key encryption method, a public key encryption method or a hybrid encryption method combining a public key encryption method and a shared key encryption method can be used. The public key encryption method is an encryption method when the encryption key (public key) and the decryption key (secret key) are different, and RSA is a typical method. When the public key cryptosystem is used, the television broadcasting station 30 broadcasts data encrypted with the public key. The hybrid encryption method creates a random session key for each data to be encrypted, encrypts the data with the session key, and then encrypts the session key with the public key of the public key encryption method. In this method, the encrypted data and the encrypted session key are broadcast together.

  Further, in this embodiment, the television broadcast station 30 broadcasts the confidential data to be broadcast with broadcast program identification information of the television program that refers to the confidential data. As this broadcast program identification information, for example, a G code (TV program identification code manufactured by US Gemster, also called VCR / PLUS) is used.

  In the confidential information decoding / playback apparatus of the first embodiment, the confidential data broadcast by the television broadcast station 30 is received and stored in the confidential information storage unit 6 as follows.

  That is, FIG. 3 shows a reception storage processing routine performed by the data processing unit 15 in this case. In the reception storage processing routine 100, first, in step 101, it is determined whether or not digital data is detected by the data detection unit 5. To do.

  In this example, the digital data is expressed in MIME (Mutpurpurse Internet Mail Extensions) syntax. FIG. 4 shows an example of the digital data expressed in the MIME syntax. The multipart type is used to store a plurality of objects in one digital data. In the example of FIG. Each object is delimited by "----------- 2424F803488".

  The first object is the content described below “Content-Type: text / control”. In the part below “Content-Type: text / control”, the television receiver 40 describes how to process the digital data. In the example of FIG. 4, the digital data is displayed. It describes the timing (or playback).

  The portion of “<program gcode = 425334 id = 32>” describes the display timing. The program identifier of the television program to display the digital data and the data identifier of the digital data in the television program Are described. That is, if the television receiver 40 receives a digital data display start command with a digital data identifier of 32 while receiving a television program with a G code number of 425334, the digital data is received at that timing. Is displayed on the television receiver 40.

  The information indicating the timing for displaying the digital data may be an absolute time or a relative time from the program start time.

  On the other hand, the second object has contents described below “Content-Type: application / encrypted-by-idea”. In the portion below “Content-Type: application / encrypted-by-idea”, secret data encrypted by the IDEA encryption method is described. Here, the syntax “application / encrypted-by-idea” is a syntax indicating that the object should be processed by executing an application that processes the IDEA encryption.

  Further, as shown in the example of FIG. 4, when there is a description of “Content-Transfer-Encoding: base64”, the encrypted confidential data is further encoded and described in the base64 format. Base64 is a method of distributing 8 bits × 3 bytes of binary data into 6 bits × 4 bytes and converting it into 7 bits of communication data.

  As a method for multiplexing a plurality of pieces of information, a packet multiplexing method conforming to MPEG-2 Systems may be used instead of using MIME encoding. In MPEG-2 Systems, a 188-byte fixed-length packet called a TS (Transport Stream) packet is used as a basic transmission unit, and the packet header of the TS packet includes a PID (Packet Identifier) for packet identification. Yes.

  When the data detection unit 5 detects the MIME data as digital data, the process proceeds to step 102, and the data detection unit 5 decodes the detected MIME data.

  In the reception storage processing routine 100, next, in step 103, the decoded data, that is, the confidential data extracted from the MIME data, the encryption method for the confidential data, and the identification information for specifying the confidential data Is stored in the secret information storage unit 6.

  FIG. 5 shows an example of the storage state in the secret information storage unit 6. As shown in the figure, the secret information storage unit 6 includes secret data, an encryption method for the secret data, and a G code (television program identifier) and ID (identification information for specifying the secret data). (Digital data identifier) is stored in association with each other.

(Operation when decrypting and playing back secret data)
After broadcasting the confidential data as described above, the television broadcast station 30 broadcasts a decryption key for decrypting the confidential data as the television program progresses. In the first embodiment, as described above, the decryption key is also broadcast using the vertical blanking period of the TV video signal.

  In the confidential information decoding / playback apparatus of the first embodiment, the decryption key broadcast by the television broadcast station 30 is received and stored in the confidential information storage unit 6 using the decryption key as follows. The secret data is decrypted and displayed as an image.

  That is, FIG. 6 shows a decoding / reproducing processing routine performed by the data processing unit 15 in this case. In the decoding / reproducing processing routine 200, first, in step 201, it is determined whether or not digital data is detected by the data detecting unit 5. To do.

  In this example, the digital data is also expressed in MIME syntax. FIG. 7 shows an example of the digital data expressed in the MIME syntax. As described above with reference to FIG. 4, the portion below “Content-Type: text / control” indicates which digital television receiver 40 has the digital data. In the example of FIG. 7, an instruction to decrypt and reproduce the confidential data stored in the confidential information storage unit 6 with the attached decryption key is given in the example of FIG. Yes.

  The syntax “<play gcode = 425334 id = 32 decryption-key-base64 = GTvb7ujJn85bBG4VfyF7G1 ==>” indicates that the secret data having the G code number 425334 and the digital data identifier 32 is stored in the secret information storage unit 6. If stored, the decryption key “GTvb7ujJn85bBG4VfyF7G1 ==” (128 bits) is used to decrypt the secret data, and if it can be decrypted normally, it instructs the television receiver 40 to display it. It is a statement. In this example, the decryption key is encoded by base64.

  When the data detection unit 5 detects the MIME data as digital data, the process proceeds to step 202, where the data detection unit 5 decodes the detected MIME data, and the decryption key extraction unit 8 decodes the MIME data. The decryption key is extracted from the obtained data.

  Next, in step 203, the secret information specifying unit 7 sets the secret data specifying information in the decoded data, that is, the information extracted from the MIME data, “gcode = 425334 id = 32” in the example of FIG. Based on the information, the secret data stored in the secret information storage unit 6 is searched, and it is determined whether or not the secret data to be decoded can be specified in conjunction with the television program.

  For example, when the viewer does not receive the television broadcast at the time of broadcasting the secret data before the start of the television program, the secret information to be specified by the secret data specifying identification information is stored in the secret information storage unit 6. Since it is not stored, it is determined in step 203 that it cannot be specified, and the process returns to step 201.

  When the secret information specifying unit 7 determines in step 203 that the secret data to be decoded can be specified in conjunction with the television program, the process proceeds to step 204, where the secret information specifying unit 7 decodes in conjunction with the television program. The secret data to be converted is identified.

  Further, in step 205, the secret information decrypting unit 9 extracts the secret data specified by the secret information specifying unit 7 and stored in the secret information storage unit 6 by the decryption key extracting unit 8 in step 202. The decryption key is decrypted using the decryption key, in the example of FIG. 7, the decryption key “GTvb7ujJn85bBG4VfyF7G1 ==”. At the time of this decryption, an encryption method stored in the secret information storage unit 6 is used.

  In the decryption / reproduction processing routine 200, the decryption key extracted by the decryption key extraction unit 8 is further stored in the decryption key storage unit 11 in step 206. In this case, as shown in FIG. 8, the decryption key storage unit 11 decrypts the decryption key, the storage time of the decryption key in the decryption key storage unit 11, and the decryption key. The storage position of the secret data stored in the secret information storage unit 6 (the value of the No column in FIG. 5) is stored in association with each other.

  In step 207, the data decoded by the secret information decoding unit 9 in step 205 is processed by the secret information reproducing unit 10 and output to the video / audio / data output unit 3. Thereby, the secret data to be displayed in conjunction with the television program is displayed together with the television image 42 as the data image 43 as shown in FIG.

  Although not shown in the decoding / playback processing routine 200, when the viewer presses the data print key 53 of the television operation remote controller 50 at the timing when the data image 43 is displayed on the television receiver 40 in this way, it is displayed at that time. The confidential data is printed by the print processing unit 13, transmitted from the infrared transmission unit 46 to the printer 60, and printed as an image by the printer 60.

(Redisplay and deletion of confidential data)
In the first embodiment, the decryption key storage unit 11 is provided and the decryption key is stored therein. Therefore, after the decryption key is stored in the decryption key storage unit 11, the viewer The secret data stored in the secret information storage unit 6 can be decrypted and redisplayed at any time by the decryption key stored in the decryption key storage unit 11.

  When redisplaying the secret data, the viewer turns the data selection dial 51 of the TV operation remote controller 50 to store the secret data recorded in the secret information storage unit 6 and the decryption key storage unit 11. The decryption keys that are currently in use are called one after another.

  As shown in FIG. 8 and described above, the decryption key storage unit 11 stores the decryption key in the decryption key storage unit 11 and the secret information stored in the decryption data using the decryption key. The storage position in the unit 6 is stored.

  When the viewer turns the data selection dial 51 to the left, the data processing unit 15 starts the decryption key stored in the decryption key storage unit 11 from the storage time stored in the decryption key storage unit 11. The decryption key is specified in order and called from the decryption key storage unit 11 and the secret data decrypted by the decryption key to be called from the secret data storage position stored in the decryption key storage unit 11 Is called from the confidential information storage unit 6.

  The called secret data is decrypted by the decryption key decryption unit 9 with the called decryption key, and the encrypted secret data is processed by the secret information reproduction unit 10 to obtain video / audio / The data is output to the data output unit 3 and redisplayed on the television receiver 40.

  Conversely, when the data selection dial 51 is turned to the right, it is decrypted by the decryption key recorded in the decryption key storage unit 11 later than the decryption key for decrypting the secret data redisplayed at that time. The confidential data is sequentially decoded and re-displayed on the television receiver 40.

  When the viewer depresses the data print key 53 of the TV operation remote controller 50 with the secret data redisplayed by operating the data selection dial 51 as described above, the secret data redisplayed at that time is displayed in the print processing unit 13. Is printed out, transmitted from the infrared transmitter 46 to the printer 60, and printed as an image by the printer 60.

  When the confidential data stored in the confidential information storage unit 6 is Internet data in HTML format as in the above example, link information may be embedded in the data. A link anchor may be designated.

  In this case, when the data of the link destination traced from the designated link anchor is the confidential data stored in the confidential information storage unit 6, the storage position of the confidential data in the confidential information storage unit 6 (FIG. 5). The secret data address column in the decryption key storage unit 11 shown in FIG. 8 is retrieved by using the No column value) as a search key, and the corresponding decryption key is specified. Then, the secret data is decrypted and re-displayed on the television receiver 40.

  The secret data stored in the secret information storage unit 6 includes information that is referred to (decoded) at the time of broadcasting a TV program, and information that is not referenced (not decoded). However, any information may be deleted when the TV program ends.

  In order to delete the secret data stored in the secret information storage unit 6 at the end of the TV program, for example, when the viewer presses the data delete key 54 of the TV operation remote controller 50 at an appropriate time, the secret information delete unit 12 detects the program end time from the broadcast time information included in the G code stored in the concealment information storage unit 6 as shown in FIG. 5, and conceals only the concealment data after the program end time. It erases from the information storage unit 6. Alternatively, the broadcast station broadcasts a signal notifying the end of the program at the end of the program, and the television receiver 40 detects this signal, and the secret information erasure unit 12 detects only the secret data that has passed the program end time, You may make it erase from the secret information storage part 6. FIG.

(Modification)
The secret data can be correctly decrypted only when a plurality of specific decryption keys are combined. In this case, in a state where the secret data is stored in the secret information storage unit 6, a plurality of decryption keys transmitted sequentially from the broadcasting station in conjunction with the television program are sequentially transmitted to the decryption key storage unit 11. When the decryption keys for decrypting the secret data are prepared, the secret data is decrypted. By doing in this way, for example, it is possible to provide useful information from a broadcasting station only to viewers who have watched all 10 times of 10 consecutive dramas.

  As a method for transmitting the secret data or the decryption key by the broadcast wave of the terrestrial television broadcast, an audio subcarrier can be used in addition to using the vertical blanking period of the TV video signal. When data is broadcast using an audio subcarrier, the data is transmitted using frequencies for two empty channels of audio signals. Since there is a transmission capacity of about 9.6 kbps per channel, Internet data of about 19.2 kbps can be broadcast for two channels.

  In the above example, the decryption key is transmitted as information independent of the television video information and the television audio information. However, the data hiding technology (Nikkei Electronics, No. 683, pp 149-162, 1997. Using 2.24), the decryption key may be embedded in the TV video information or TV audio information and broadcast. In this case, the decryption key extraction unit 8 extracts the decryption key from the video information or audio information from the analog demodulation unit 2 and outputs it to the system bus 4.

  As described above, when broadcasting with the decryption key embedded in the TV video information or TV audio information, the decryption key can be held in the recorded TV video information or TV audio information even after video recording. The secret information related to the video image can be decoded and displayed while the video image is reproduced and displayed.

  The above example is a case where a broadcast station broadcasts confidential data. As a method of distributing the confidential data to the viewer, the broadcast station or the like stores the confidential data in a storage medium such as a CDROM. The storage medium itself may be distributed to viewers. In this case, the recording medium constitutes the secret information storage unit 6.

  Furthermore, the first embodiment described above can also be applied to a digital television broadcast transmission / reception system. For example, even in satellite digital television broadcasting using artificial satellites, an attempt to multiplex and broadcast Internet data in HTML format on digitized TV video information and television audio information has been started, and when this satellite data broadcast is received Can receive Internet data transmitted at a high speed of about 1.5 Mbps.

(effect)
According to the first embodiment described above, confidential information that only a person who has watched a television program can know can be distributed in advance prior to the broadcast of the television program, and the confidential information can be distributed to an unspecified number of viewers. Even in the case of distribution, it is possible to give the right to know information only to viewers who watch TV programs.

  In addition, the disclosure / non-disclosure of information can be changed dynamically according to the progress of the TV program, and when the same confidential information is used in multiple scenes or programs, the confidential information once distributed Can be reused.

  Furthermore, the viewer is not forced to decrypt the confidential information and can concentrate on the TV program being viewed. Also, secret information provided to viewers by media other than broadcasting such as CDROM can be decoded and played back in conjunction with a television program.

[Second Embodiment]
In the first embodiment, the broadcast station distributes an encrypted Web page to an unspecified number of viewers in advance, and only the viewer who has watched a TV program can view the contents of the secret Web page. It is a case where it can be seen.

  On the other hand, the second embodiment is a case where a Web page that allows access only to a specific viewer permitted by the information provider is broadcast. That is, in the second embodiment, the broadcast station broadcasts a secret Web page prior to the start of the television program, and only viewers permitted by the broadcast station (information provider) can follow the progress of the television program, The secret Web page can be read and viewed.

  In the second embodiment, the present invention is applied to a satellite digital television broadcast transmission / reception system. The receiver that receives this satellite digital television broadcast is, for example, PerfecTV! It is a receiver that receives broadcasts.

(Constitution)
In the second embodiment, an IC card can be attached to the television receiver. As shown in FIG. 10, in the IC card 81, a calculation unit 83 is provided in addition to the memory unit 82, and the user ID and the user key Ku are stored in the memory unit 82. The calculation unit 83 performs a key decryption calculation as will be described later.

  The user key Ku is a key used for identifying whether or not the viewer has the right to decrypt the confidential data distributed by broadcasting, and is different for each viewer. Note that a decryption key that is used for decrypting video scramble, such as satellite digital television broadcasting, may be used as the user key Ku of this embodiment.

  In the second embodiment, the broadcasting station, as shown in FIG. 9, a broadcasting station database 71 includes a broadcasting data management database 72 for managing broadcasting data, and a user management database 73 for managing user information. The broadcast data management database 72 holds the broadcast data, the encryption / decryption key Ke, and the secret data specifying information, and the user management database 73 contains the destination user ID and the user key Ku of the destination user. Shall be retained.

  The broadcast data in the broadcast data management database 72 is data that is encrypted to be confidential data.

  The key Ke is an encryption key for encrypting the broadcast data, and a decryption key for decrypting the secret data encrypted by the key Ke. That is, in the second embodiment, a shared key cryptosystem is used in which an encryption key for encrypting information and a decryption key for decrypting this encryption are the same key.

  However, as an encryption method for encrypting data, besides the shared key encryption method, a public key encryption method or a hybrid encryption method combining a public key encryption method and a shared key encryption method may be used. For example, when the public key cryptosystem is used, the encryption key Ke and the decryption key Ke are generated so as to form a public key pair.

  The secret data specifying information in the broadcast data management database 72 is identification information for specifying the secret data, and is, for example, a G code as a broadcast program identifier and a digital data identifier.

  The user key Ku in the user management database 73 is a key for encrypting the key Ke. That is, in the user management database 73 of the broadcasting station, the same user key (second encryption key) as the user key (second decryption key) Ku stored in the IC card 81 held by each viewer. Ku is held. Accordingly, the decryption key Ke encrypted with the user key Ku held in the user management database 73 can be extracted by decrypting with the user key Ku stored in the IC card 81 held by the viewer. Become.

  In this case as well, a public key encryption method or a hybrid encryption method combining a public key encryption method and a shared key encryption method may be used. For example, the user key Ku held in the user management database 73 and the user key Ku stored in the IC card 81 held by each viewer are generated so as to form a public key pair.

(Operation when receiving and storing confidential data)
Prior to the start of the television program, the broadcast station broadcasts the confidential data, and the television receiver receives the broadcast confidential data and stores it in the confidential information storage unit.

  Specifically, as shown in FIG. 11, the television broadcast station 70 creates a random encryption key Ke for each broadcast data to be encrypted, and the data encryption unit 74 uses the encryption key Ke to broadcast data. Is encrypted, and the encrypted confidential data is broadcast at a time before the start time of the television program.

  In this case, in the MIME encoder 75, for the encrypted confidential data, a destination user ID list for designating a viewer who should receive the confidential data, and the confidential data can be specified later. The secret data specifying information, for example, the G code and the digital data identifier are multiplexed and broadcast.

  As shown in FIG. 12, in the television receiver 40, the MIME decoder 21 receives the encrypted confidential data, the destination user ID list, and the confidential data specifying information from the multiplexed broadcast signal from the television broadcast station 70. The destination collation unit 22 collates whether or not the user ID stored in the IC card 81 is included in the destination user ID list.

  If the user ID is included in the destination user ID list, the received confidential data and the confidential data specifying information are addressed to the user, and the confidential data and the confidential data specifying information are stored in the confidential information storage unit. 6 is stored. In this case, as shown in FIG. 5, the secret information storage unit 6 stores the secret data, the encryption method for the secret data, and the secret data specifying information in association with each other.

(Operation when decrypting and playing back secret data)
The broadcasting station encrypts the decryption key Ke for decrypting the secret data to be decrypted in conjunction with the TV program by the user key Ku of the viewer who has the right to correctly decrypt the secret data. Broadcast along with the progress of the TV program.

  That is, as shown in FIG. 13, in the television broadcast station 70, the key encryption unit 76 sends the decryption key Ke (the same key as the encryption key Ke when the secret data is encrypted) to the destination viewer. A unique user key Ku (the same key as the user key Ku in the IC card 81 of the destination viewer) is encrypted by the number of destination viewers, and a list of the decrypted decryption keys Ke ′ is converted to a television program. Broadcast in line with progress.

  In this case, the MIME encoder 75 uses the destination user ID list for designating the destination viewer of the decryption key Ke ′ and the decryption key Ke ′ for the list of the encrypted decryption keys Ke ′. The secret data specifying information for specifying the secret data to be decoded, for example, the G code and the digital data identifier are multiplexed and broadcast.

  As shown in FIG. 14, in the television receiver 40, the MIME decoder 21 makes a list of encrypted decryption keys Ke ′, a destination user ID list, and a destination user ID list from the multiplexed broadcast signal from the television broadcast station 70. The secret data specifying information is separated, and the destination collation unit 22 collates whether or not the user ID stored in the memory unit 82 of the IC card 81 is included in the destination user ID list.

  When the user ID is included in the destination user ID list, the received decryption key Ke ′ and the secret data specifying information received by the user are calculated in the IC card 81. In the unit 83, the encrypted decryption key Ke ′ is decrypted with the user key Ku unique to itself, which is owned in the memory unit 82 of the IC card 81, and the decryption key Ke is extracted.

  At the same time, when the user ID is included in the destination user ID list, the secret information specifying unit 7 is separated by the MIME decoder 21 from the secret data stored in the secret information storage unit 6. The secret data specified by the secret data specifying information is specified, and the secret information decoding unit 9 further stores the secret data specified by the secret information specifying unit 7 and read from the secret information storage unit 6 as an IC card. Decryption is performed using the decryption key Ke obtained from the calculation unit 83 in 81.

  The decrypted secret data is processed by the secret information reproducing unit 10, output to the video / audio / data output unit 3, and displayed on the display screen of the television receiver 40.

(effect)
According to the second embodiment, even when the television receiver 40 is modified so that the viewer can illegally receive confidential data addressed to others, the television broadcast station 70 encrypts the decryption key Ke. If the used user key Ku and the user key Ku stored in the viewer's IC card 81 do not match, the confidential data cannot be correctly decrypted, so that the security of the system is guaranteed.

[Third Embodiment]
In the second embodiment, when a web page that allows access only to a specific viewer permitted by the information provider is broadcast, the decryption key Ke for decrypting the secret web page that has already been broadcast is transmitted to the destination. The user key Ku unique to the subscriber encrypts and broadcasts the number of destination viewers, and has the feature that the broadcasting system of the broadcasting station and the receiving system on the receiving side can be made relatively simple, but synchronized with the TV program Since the encrypted decryption key Ke ′ that is different for each destination viewer is broadcast at the same timing, when the number of destination viewers is large, the decryption key may be transmitted in accordance with the progress of the TV program. It can be difficult.

  Therefore, in the third embodiment, when secret data is broadcast prior to the start of a television program, the decryption key for decrypting the secret data is encrypted and broadcast together with the secret data, and then the television Broadcasting a decryption key for decrypting the previously decrypted encrypted decryption key as the program progresses, and decrypting the confidential data using the decryption key obtained thereby It is.

  In this case, the encrypted decryption key that is broadcast together with the confidential data is an individual decryption key that is different for each viewer, and the decryption key that is broadcast according to the progress of the TV program is common to all viewers. This is the decryption key.

  According to the third embodiment, even when there are many decryption key destinations for decrypting the confidential data, only one decryption key is required to be broadcast in accordance with the progress of the television program. There is nothing that makes it difficult to transmit the decryption key as the TV program progresses.

  In the third embodiment, as in the second embodiment, the present invention is applied to a satellite digital television broadcast transmission / reception system. The receiver that receives this satellite digital television broadcast is, for example, PerfecTV! It is a receiver that receives broadcasts.

(Constitution)
In the third embodiment, similarly to the second embodiment, an IC card can be attached to the television receiver. Similar to the second embodiment, the user key Ku is stored in the memory unit 82 of the IC card 81 as shown in FIG. As in the second embodiment, this user key Ku is a key used to identify whether or not the viewer has the right to decrypt the confidential data distributed by broadcasting. Everything is different.

  As in the second embodiment, the IC card 81 includes an arithmetic unit 83 inside. In the third embodiment, as shown in FIG. 17, the television receiver 40 further includes an encryption key storage unit 23.

  As for the broadcast station database 71, in the third embodiment, as shown in FIG. 15, the broadcast data management database 72 includes the third encryption / decryption key Ke as the first encryption key. The encryption / decryption key Kc as the encryption key is held. The user management database 73 holds the user key Ku as the second encryption key as in the second embodiment.

  The encryption / decryption key Kc as the third encryption key is a key that is broadcast as the television program progresses, and is common to all viewers.

(Operation when receiving and storing confidential data)
Prior to the start of the television program, the broadcasting station encrypts the first encryption key Ke with the second encryption key Ku, and further converts the encrypted encryption key Ke ′ into the third encryption key Kc. And the encrypted encryption key Ke ″ and the secret data are broadcasted, and the television receiver receives the broadcast secret data and the encrypted encryption key Ke ″, The secret data is stored in the secret information storage unit, and the encrypted encryption key Ke ″ is stored in the encryption key storage unit.

  That is, as shown in FIG. 16, the television broadcasting station 70 creates a random first encryption key Ke and third encryption key Kc for each broadcast data to be encrypted, and the data encryption unit 74 The broadcast data is encrypted with the first encryption key Ke, and the encrypted confidential data is sent to the MIME encoder 75.

  Further, the key encryption unit 76 encrypts the first decryption key Ke by the number of destination viewers by using the second encryption key (user key) Ku unique to the destination viewer. A list of encryption keys Ke ′ is obtained. Further, the key encryption unit 77 encrypts the list of the encrypted encryption keys Ke ′ with the third encryption key Kc, and converts the list of the encrypted encryption keys Ke ″ into the MIME encoder. 75.

  Then, the MIME encoder 75 multiplexes the encrypted secret data, the list of encrypted encryption keys Ke ″, the destination user ID list, and the secret data specifying information, and the time point before the start time of the television program Broadcast on.

  As shown in FIG. 17, in the television receiver 40, the MIME decoder 21 makes a list of encrypted secret data and encrypted encryption key Ke ″ from the multiplexed broadcast signal from the television broadcast station 70. The destination user ID list and the confidential data specifying information are separated, and the destination verification unit 22 verifies whether or not the user ID stored in the IC card 81 is included in the destination user ID list. .

  If the user ID is included in the destination user ID list, the received confidential data and the encrypted encryption key Ke ″ are addressed to the user, and the confidential data and the confidential data are specified. The information is stored in the secret information storage unit 6, and the encrypted encryption key Ke ″ is stored in the encryption key storage unit 23.

  In this case, as shown in FIG. 5, the secret information storage unit 6 stores the secret data, the encryption method for the secret data, and the secret data specifying information in association with each other, and stores the secret data stored in the secret data. The storage position (the value of the No column in FIG. 5) in the secret information storage unit 6 is output to the encryption key storage unit 23, and the encryption key storage unit 23 performs encrypted encryption as shown in FIG. The key Ke ″ and the storage position of the confidential data input from the confidential information storage unit 6 in the confidential information storage unit 6 are stored in association with each other.

(Operation when decrypting and playing back secret data)
The broadcast station broadcasts the third encryption key Kc as the decryption key for decrypting the secret data to be decrypted in conjunction with the television program as the television program progresses.

  That is, as shown in FIG. 19, in the television broadcasting station 70, the MIME encoder 75 specifies the decryption key (third encryption key) Kc and the secret data to be decrypted by the decryption key Kc. The secret data specifying information is multiplexed and broadcast as the TV program progresses.

  As shown in FIG. 20, in the television receiver 40, the MIME decoder 21 separates the decryption key Kc and the secret data specifying information from the multiplexed broadcast signal from the television broadcast station 70. And the secret information specific | specification part 7 specified the secret data specified by the secret data specific information isolate | separated by the MIME decoder 21 among the secret data memorize | stored in the secret information storage part 6, and specified the The storage position of the secret data in the secret information storage unit 6 is output from the secret information storage unit 6 to the encryption key storage unit 23.

  As a result, as shown in FIG. 18, the encrypted encryption key Ke ″ stored in the encryption key storage unit 23 corresponding to the storage position of the secret data in the secret information storage unit 6 is encrypted. The key storage unit 23 outputs to the key decryption unit 24, and the key decryption unit 24 decrypts the encrypted encryption key Ke ″ with the decryption key Kc separated by the MIME decoder 21. An encrypted encryption key Ke ′ is output from the decryption unit 24.

  Further, in the calculation unit 83 in the IC card 81, the encrypted encryption key Ke ′ is decrypted by the user key Ku stored in the memory unit 82 of the IC card 81, and from the calculation unit 83, A decryption key (first encryption key) Ke is obtained.

  Then, in the secret information decryption unit 9, the secret data specified by the secret information specifying unit 7 and read from the secret information storage unit 6 is decrypted with the decryption key Ke obtained from the calculation unit 83. The decrypted secret data is processed by the secret information reproducing unit 10, output to the video / audio / data output unit 3, and displayed on the display screen of the television receiver 40.

(effect)
According to the third embodiment, similarly to the second embodiment, even when the television receiver 40 is modified so that the viewer can illegally receive the confidential data addressed to others, the television broadcast station 70 decodes the data. If the user key Ku used for encrypting the encryption key Ke and the user key Ku stored in the viewer's IC card 81 do not match, the confidential data cannot be correctly decrypted. System safety is guaranteed.

  Furthermore, even when there are many decryption key destinations for decrypting confidential data, only one decryption key is required to be broadcast in accordance with the progress of the TV program, so that the decryption is performed in accordance with the progress of the TV program. There is nothing that makes it difficult to send the encryption key.

[Fourth Embodiment]
The fourth embodiment is a modification of the third embodiment. As shown in FIG. 16, in the third embodiment, the broadcasting station uses the second encryption key (user key) Ku unique to the destination viewer for the first encryption key Ke obtained by encrypting the broadcast data. In this case, encryption is performed by the number of destination viewers, and then encryption is performed using a third encryption key Kc common to all viewers.

  On the other hand, in the fourth embodiment, the broadcast station encrypts the first encryption key Ke obtained by encrypting broadcast data with the third encryption key Kc common to all viewers, and then views the destination. The number of destination viewers is encrypted with a second encryption key (user key) Ku unique to the user.

  Thereby, the encryption processing time of the broadcast station can be shortened. Furthermore, according to the fourth embodiment, there is an effect that it is not necessary for the television receiver to access the IC card when data is decoded in accordance with the progress of the television program.

(Operation when receiving and storing confidential data)
Prior to the start of the television program, the broadcasting station encrypts the first encryption key Ke with the third encryption key Kc, and further converts the encrypted encryption key Ke ′ into the second encryption key Ku. And the encrypted encryption key Ke ″ and the secret data are broadcast.

  That is, as shown in FIG. 21, the television broadcasting station 70 creates a random first encryption key Ke and third encryption key Kc for each broadcast data to be encrypted, and the data encryption unit 74 The broadcast data is encrypted with the first encryption key Ke, and the encrypted confidential data is sent to the MIME encoder 75.

  Further, the key encryption unit 76 encrypts the first decryption key Ke with the third encryption key Kc common to all viewers, and obtains the encrypted encryption key Ke ′. Further, the key encryption unit 77 encrypts the encrypted encryption key Ke ′ by the number of destination viewers with the second encryption key (user key) Ku unique to the destination viewers, and A list of encrypted encryption keys Ke ″ is sent to the MIME encoder 75.

  Then, the MIME encoder 75 multiplexes the encrypted secret data, the list of encrypted encryption keys Ke ″, the destination user ID list, and the secret data specifying information, and the time point before the start time of the television program Broadcast on.

  As shown in FIG. 22, in the television receiver 40, the MIME decoder 21 makes a list of encrypted secret data and encrypted encryption key Ke ″ from the multiplexed broadcast signal from the television broadcast station 70. The destination user ID list and the confidential data specifying information are separated, and the destination verification unit 22 verifies whether or not the user ID stored in the IC card 81 is included in the destination user ID list. .

  Then, when the user ID is included in the destination user ID list, the arithmetic unit in the IC card 81 uses the received confidential data and the encrypted encryption key Ke ″ as the one addressed to itself. In 83, the encrypted encryption key Ke ″ is decrypted with the user key Ku unique to itself, which is owned in the memory unit 82 of the IC card 81, and is encrypted. Take out.

  Then, the secret data and the secret data specifying information separated by the MIME decoder 21 are stored in the secret information storage unit 6, and the encrypted encryption key Ke ′ obtained from the calculation unit 83 is stored in the encryption key storage unit 23.

  In this case, as shown in FIG. 5, the secret information storage unit 6 stores the secret data, the encryption method for the secret data, and the secret data specifying information in association with each other and stores the secret data stored in the secret data. The storage position (the value of the No column in FIG. 5) in the secret information storage unit 6 is output to the encryption key storage unit 23, and the encryption key storage unit 23 performs encrypted encryption as shown in FIG. The key Ke ′ and the storage position of the confidential data input from the confidential information storage unit 6 in the confidential information storage unit 6 are stored in association with each other.

(Operation when decrypting and playing back secret data)
The broadcast station broadcasts the third encryption key Kc as the decryption key for decrypting the secret data to be decrypted in conjunction with the television program as the television program progresses.

  That is, as shown in FIG. 24, in the television broadcast station 70, the MIME encoder 75 specifies the decryption key (third encryption key) Kc and the secret data to be decrypted by the decryption key Kc. The secret data specifying information is multiplexed and broadcast as the TV program progresses.

  As shown in FIG. 25, in the television receiver 40, the MIME decoder 21 separates the decryption key Kc and the secret data specifying information from the multiplexed broadcast signal from the television broadcast station 70. And the secret information specific | specification part 7 specified the secret data specified by the secret data specific information isolate | separated by the MIME decoder 21 among the secret data memorize | stored in the secret information storage part 6, and specified the The storage position of the secret data in the secret information storage unit 6 is output from the secret information storage unit 6 to the encryption key storage unit 23.

  Accordingly, as shown in FIG. 23, the encrypted encryption key Ke ′ stored in the encryption key storage unit 23 corresponding to the storage position of the secret data in the secret information storage unit 6 is encrypted. The key storage unit 23 outputs the key to the key decryption unit 24, and the key decryption unit 24 decrypts the encrypted encryption key Ke ′ with the decryption key Kc separated by the MIME decoder 21 to obtain the key. A decryption key (first encryption key) Ke is output from the decryption unit 24.

  Then, in the secret information decryption unit 9, the secret data specified by the secret information specifying unit 7 and read from the secret information storage unit 6 is decrypted by the decryption key Ke obtained from the key decryption unit 24. The The decrypted secret data is processed by the secret information reproducing unit 10, output to the video / audio / data output unit 3, and displayed on the display screen of the television receiver 40.

(effect)
According to the fourth embodiment, as in the second or third embodiment, even when the viewer has illegally modified the television receiver 40 so that it can receive confidential data addressed to others, the television broadcast station If the user key Ku used for encrypting the decryption key Ke does not match the user key Ku stored in the viewer's IC card 81, the secret data can be correctly decrypted. Since this is not possible, the safety of the system is guaranteed.

  Similarly to the third embodiment, even when there are many decryption key destinations for decrypting confidential data, only one decryption key is required to be broadcast in accordance with the progress of the television program. There is nothing that makes it difficult to transmit the decryption key as the TV program progresses.

  Furthermore, it is not necessary for the television receiver 40 to access the IC card 81 when data is decoded as the television program progresses.

[Other Embodiments]
Each of the embodiments described above is a case where the present invention is applied to a television broadcast transmission / reception system, but the present invention can also be applied to a radio broadcast transmission / reception system.

  The confidential information or the data to be superimposed on the TV broadcast signal or radio broadcast signal includes information multiplexed during the vertical blanking period of the TV broadcast signal transmitted by radio wave or cable, and the audio sub-data of TV broadcast or radio broadcast Information transmitted by channel, information transmitted by audio subcarrier of TV broadcast or radio broadcast, information combined with digital TV broadcast, or hidden information embedded in video or audio information of TV broadcast or radio broadcast However, the present invention can be applied to any of these cases.

[Various embodiments and effects]
In the present invention, the following effects can be obtained by employing the following embodiments.

  (1) The broadcasting station broadcasts a decryption key for decrypting the secret data and secret data specifying information for specifying the secret data to which the decryption key is applied in accordance with the progress of the TV video program. The television receiver receives the broadcast decryption key and the secret data specifying information, and stores the secret data specified by the secret data specifying information out of the secret data stored in the storage medium. With this configuration, even if data is distributed in advance to an unspecified number of people, only viewers who watch TV programs can view the contents of this data. Thus, the broadcasting station can provide data useful only to viewers who watched the television program.

  (2) The broadcast receiver receives the broadcast decryption key and the secret data specifying information, and decrypts the secret data specified by the secret data specifying information out of the secret data stored in the storage medium. When viewers who watch a TV program view the contents of this data by decrypting the data with a key and displaying the decoded data on a TV receiver in accordance with the progress of the TV video program However, the user is not forced to decrypt the secret data, and can concentrate on the TV program being viewed.

  (3) By configuring so that the decryption key broadcast by the broadcast station can be stored, the viewer can decrypt and display the confidential data at any time after the decryption key is stored. it can.

  (4) When a broadcast station broadcasts broadcast program identification information together with a decryption key for decrypting secret data, the broadcast receiver receives the broadcast program identification information broadcasted by the television receiver, and a storage medium Among the secret data stored in the TV, the secret data related to the TV program specified by the broadcast program identification information is decrypted by the decryption key, so that the TV can be transmitted to an unspecified number of viewers. Even if data related to a program has been distributed in advance, only viewers who watched the TV program can view the contents of this data, so that the broadcast station saw the TV program. Data useful only to viewers can be provided.

  (5) When the decryption key broadcast from the broadcasting station is received by the television receiver, based on the television channel number being viewed and the decryption key reception time among the secret data stored in the storage medium. Even if the broadcast program identification information is not broadcast from the broadcast station, the secret data corresponding to the received decryption key is specified among the secret data stored in the storage medium. It is possible to identify the confidential data related to the TV program in the program, so that only the viewer who has watched the TV program can view the contents of the secret data, so that the broadcasting station can watch the TV program. It can provide useful data only to the viewers.

  (6) Concealed data is stored in a storage medium by adding index information or the like so that it can be specified by the secret data specifying information broadcast from the broadcast station, so that the broadcast content being broadcast can be reduced. Since related confidential data can be specified, for example, even in the same television program, the disclosure / non-disclosure of information can be dynamically changed in accordance with the progress of the television broadcast program.

  (7) When the broadcast station broadcasts the confidential data at a time before the TV program broadcast start time, the TV receiver is configured to store the broadcast confidential data in the storage medium, thereby allowing the broadcast station to Since when the decryption key for decrypting the secret data is broadcast in conjunction with the TV program broadcast, the secret data stored in the storage medium can be decrypted with the decryption key. Even if data has been distributed in advance to an unspecified number of viewers, only viewers who have watched a TV program can view the contents of this data. Data useful only to viewers who watch TV programs can be provided.

  (8) The broadcast station matches the first decryption key for decrypting the secret data and the secret data specifying information for specifying the secret data to which the decryption key is applied, in accordance with the progress of the TV video program. The TV receiver receives the broadcasted first decryption key and the secret data specifying information, and the secret data specified by the secret data specifying information out of the secret data stored in the storage medium. By configuring the data to be decrypted with the first decryption key and the second decryption key input from an IC card memory or the like, the data is distributed in advance to an unspecified number of viewers. Even in such a case, only a specific person can be given the right to view the data, so that the broadcast station can provide useful data only to a specific viewer.

  (9) The television receiver receives the broadcasted first decryption key and the secret data specifying information, and the secret data specified by the secret data specifying information is stored in the secret data stored in the storage medium. When data is distributed in advance to an unspecified number of viewers by configuring the decryption using the first decryption key and the second decryption key owned by each viewer. However, only the viewer who has the right to decrypt the confidential data can view the contents of the data, so that the broadcasting station can provide useful data only for a specific viewer.

  (10) The broadcast station encrypts the decryption key for decrypting the confidential data with the encryption key, broadcasts the encrypted decryption key in accordance with the progress of the television video program, and the television receiver. The encrypted decryption key broadcasted is decrypted with the second decryption key input from the IC card memory or the like, and the secret data is decrypted using the decryption key extracted thereby. By configuring, even if the data has been distributed in advance to an unspecified number of viewers, it becomes possible to give the right to view the data only to a specific person. Data useful only to specific viewers can be provided.

  (11) The broadcast station encrypts the decryption key for decrypting the confidential data with the encryption key, and broadcasts the encrypted decryption key in accordance with the progress of the television video program. The encrypted decryption key broadcasted is decrypted with the second decryption key input from the IC card memory or the like, and the secret data is decrypted using the decryption key extracted thereby. By configuring, even when data is distributed in advance to an unspecified number of viewers, only viewers who have the right to decrypt confidential data can see the contents of the data. The broadcaster can provide data that is useful only to specific viewers.

  (12) The broadcast station uses the first decryption key common to all viewers or all receivers for decrypting the secret data, and the secret data specifying information for specifying the secret data to which the decryption key is to be applied. The TV receiver receives the broadcasted first decryption key and the secret data specifying information, and transmits the secret data stored in the storage medium. The secret data specified by the secret data specifying information is decrypted with the first decryption key and an individual second decryption key which is different for each viewer or receiver input from an IC card memory or the like. With this configuration, even when data is distributed in advance to an unspecified number of viewers, only a specific person can be given the right to view the data. Is specific It is possible to provide useful data only to the viewer.

  (13) The secret data stored in the secret information storage unit is encrypted with the first encryption key, and the encryption key information stored in the encryption key information storage unit is the first encryption. When the first decryption key corresponding to the key is information encrypted using a separate second encryption key and a third encryption key that are different for each viewer or receiver, The television receiver has a third decryption key corresponding to the third encryption key broadcast in accordance with the progress of the TV video program, and a second encryption key input from the IC card memory or the like. The first decryption key is extracted from the encryption key information stored in the encryption key information storage unit using the decryption key 2 and stored in the secret information storage unit using the first decryption key. By configuring the stored confidential data to be decrypted, it is possible to decrypt data for an unspecified number of viewers. Even if the data has been distributed in advance, only a specific person can be given the right to view the data, and the broadcast station can transmit the third decryption key corresponding to the third encryption key when broadcasting the TV program. Since it is only necessary to broadcast the encryption key, it is possible to cope with a case where the number of destination viewers of the decryption key is large.

  (14) The secret data stored in the secret information storage unit is encrypted with the first encryption key, and the encryption key information input from the encryption key information input unit is the first encryption key. The first decryption key corresponding to the encryption key is encrypted using the third encryption key, and the encrypted information is further used for each viewer or receiver using a different second encryption key. If the information is encrypted, the television receiver uses the second decryption key corresponding to the second encryption key input from the IC card memory or the like to input from the encryption key information input unit. The decrypted encryption key information is decrypted, and the decrypted encryption key information is stored in the encryption key information storage unit. Further, the television receiver performs a third process according to the progress of the television video program. When the third decryption key corresponding to the encryption key is broadcast, this The decryption key 3 is used to decrypt the encryption key information stored in the encryption key information storage unit, and a first decryption key corresponding to the first encryption key is extracted, and this first decryption key is extracted. Even if data is distributed in advance to an unspecified number of viewers by configuring the secret data stored in the secret information storage unit to be decrypted using the encryption key, only a specific person And the broadcast station only has to broadcast a third decryption key corresponding to the third encryption key when the TV program is broadcast, and the television receiver Since it is not necessary to access the IC card when receiving a TV program, it is possible to cope with a case where the number of destination viewers of the decryption key is large, and to speed up the confidential data decryption processing of the television receiver. Can do.

  (15) The secret data stored in the secret information storage unit is encrypted with the first encryption key, and the encryption key information stored in the encryption key information storage unit is the first encryption key. When the second decryption key corresponding to the encryption key is information encrypted using the individual second encryption key and the third encryption key that are different for each viewer or receiver. The television receiver has the same third decryption key corresponding to the third encryption key broadcast as the TV video program progresses, and the same second encryption key input from the IC card memory or the like. Using the second decryption key that is a key, the first decryption key is extracted from the encryption key information stored in the encryption key information storage unit, and is concealed using this first decryption key By configuring it to decrypt the confidential data stored in the information storage unit, Even if the data is distributed in advance, only a specific person can be given the right to view the data, and the broadcast station can transmit the third encryption key corresponding to the third encryption key when broadcasting the TV program. Therefore, it is possible to cope with a case where the number of destination viewers of the decryption key is large.

  (16) The secret data stored in the secret information storage unit is encrypted with the first encryption key, and the encryption key information stored in the encryption key information storage unit is the first encryption key. When the first decryption key corresponding to the encryption key is information encrypted using a separate second encryption key and a third encryption key that are different for each viewer or receiver. The television receiver has a third decryption key corresponding to the third encryption key broadcast in accordance with the progress of the TV video program, a second encryption key and a public key input from an IC card memory or the like. Using the paired second decryption key, the first decryption key is extracted from the encryption key information stored in the encryption key information storage unit, and concealed using the first decryption key An unspecified number of viewers can be configured to decrypt the confidential data stored in the information storage unit. On the other hand, even when data is distributed in advance, only a specific person can be given the right to view the data, and the broadcast station can transmit the third encryption key corresponding to the third encryption key when broadcasting a TV program. The second decryption key held by the viewer can be kept secret from the broadcast station.

  (17) The secret data stored in the secret information storage unit is encrypted with the first encryption key common to all viewers or all receivers, and stored in the encryption key information storage unit The encryption key information includes a first decryption key corresponding to the first encryption key, an individual second encryption key that is different for each viewer or receiver, and common to all viewers or all receivers. When the information is encrypted using the third encryption key, the television receiver uses the third decryption key corresponding to the third encryption key broadcasted in accordance with the progress of the television video program. Using the encryption key and the second decryption key corresponding to the second encryption key input from the IC card memory or the like, the first decryption is performed from the encryption key information stored in the encryption key information storage unit. The encryption key is extracted, and the secret data stored in the secret information storage unit is restored using the first decryption key. Even if the data is distributed in advance to an unspecified number of viewers, the right to view the data can be given only to a specific person. When broadcasting a TV program, it is only necessary to broadcast the third decryption key corresponding to the third encryption key, so that it is possible to cope with a case where the number of destination viewers of the decryption key is large.

  (18) The secret data stored in the secret information storage unit is encrypted with the first encryption key common to all viewers or all receivers, and is input from the encryption key information input unit The encryption key information encrypts the first decryption key corresponding to the first encryption key using the third encryption key common to all viewers or all receivers, and this encrypted information. Is further encrypted using an individual second encryption key that is different for each viewer or receiver, the TV receiver uses the second encryption key input from the IC card memory or the like. The encryption key information input from the encryption key information input unit is decrypted using the corresponding second decryption key, and the decrypted encryption key information is stored in the encryption key information storage unit. In addition, the television receiver is adapted to the progress of the television video program. When the third decryption key corresponding to the encryption key is broadcast, the encryption key information stored in the encryption key information storage unit is decrypted with the third decryption key, and the first decryption key is decrypted. Unspecified by extracting a first decryption key corresponding to the encryption key and decrypting the secret data stored in the secret information storage unit using the first decryption key Even when data is distributed in advance to a large number of viewers, only a specific person can be given the right to view the data, and the broadcast station can transmit the third encryption key when broadcasting a TV program. It is only necessary to broadcast the third decryption key corresponding to, and the TV receiver does not need to access the IC card memory when receiving the TV program. Can handle many cases and conceal TV receiver It is possible to speed up the chromatography data decoding process.

  (19) The broadcast receiver receives the broadcast decryption key and the secret data specifying information, and decrypts the secret data specified by the secret data specifying information out of the secret data stored in the storage medium. By configuring the decrypted data with a key so that the decrypted data can be output to a printer and printed in accordance with the progress of the TV video program, the viewer is not forced to decrypt the confidential data, You can concentrate on the TV program you are watching.

It is a figure which shows the system configuration | structure of 1st Embodiment. It is a figure which shows the functional block structure of 1st Embodiment. It is a figure which shows the reception storage process routine of 1st Embodiment. It is a figure which shows an example of the confidential data of 1st Embodiment. It is a figure which shows an example of the memory | storage state of the confidential information storage part of 1st Embodiment. It is a figure which shows the decoding reproduction | regeneration processing routine of 1st Embodiment. It is a figure which shows an example of the decryption key of 1st Embodiment. It is a figure which shows an example of the memory | storage state of the decryption key memory | storage part of 1st Embodiment. It is a figure which shows the broadcasting station database of 2nd Embodiment. It is a figure which shows the IC card with which the television receiver of 2nd Embodiment is mounted | worn. It is a figure which shows the function structure of the broadcast station at the time of the confidential data broadcast of 2nd Embodiment. It is a figure which shows the function structure of the receiver at the time of the confidential data reception of 2nd Embodiment. It is a figure which shows the function structure of the broadcasting station at the time of the decoding key broadcast of 2nd Embodiment. It is a figure which shows the function structure of the receiver at the time of the decoding key reception of 2nd Embodiment. It is a figure which shows the broadcasting station database of 3rd Embodiment. It is a figure which shows the function structure of the broadcasting station at the time of the confidential data broadcast of 3rd Embodiment. It is a figure which shows the function structure of the receiver at the time of confidential data reception of 3rd Embodiment. It is a figure which shows an example of the memory | storage state of the encryption key memory | storage part of 3rd Embodiment. It is a figure which shows the function structure of the broadcasting station at the time of the decoding key broadcast of 3rd Embodiment. It is a figure which shows the function structure of the receiver at the time of the decoding key reception of 3rd Embodiment. It is a figure which shows the function structure of the broadcasting station at the time of the confidential data broadcast of 4th Embodiment. It is a figure which shows the function structure of the receiver at the time of the confidential data reception of 4th Embodiment. It is a figure which shows an example of the memory | storage state of the encryption key memory | storage part of 4th Embodiment. It is a figure which shows the function structure of the broadcasting station at the time of the decoding key broadcast of 4th Embodiment. It is a figure which shows the function structure of the receiver at the time of the decoding key reception of 4th Embodiment.

Explanation of symbols

  Since all the main parts are described in the figure, they are omitted here.

Claims (15)

Confidential information storage means for storing encrypted information as confidential information;
Video / audio information receiving means for receiving video / audio information which is video information or audio information transmitted from a transmission source;
Video / audio information reproducing means for reproducing the video / audio information received by the video / audio information receiving means;
Data detection means for detecting data superimposed on the video and audio information;
Based on information included in the data detected by the data detection means, confidential information specifying means for specifying the confidential information to be decoded out of the confidential information stored in the confidential information storage means,
A decryption key extracting means for extracting a decryption key for decrypting the confidential information specified by the confidential information specifying means from information included in the data detected by the data detecting means;
Of the confidential information stored in the confidential information storage means, the confidential information decrypting means for decrypting the confidential information specified by the confidential information specifying means with the decryption key extracted by the decryption key extracting means When,
Confidential information reproducing means for reproducing the confidential information decoded by the confidential information decoding means;
A secret information decoding / reproducing apparatus comprising: The secret information decoding / reproducing apparatus according to claim 1,
The secret information stored in the secret information storage means is superimposed on the video / audio information at a time before the time when a decryption key for decrypting the secret information is extracted by the decryption key extraction means. The secret information decoding / reproducing apparatus, wherein the secret information decoding / reproducing apparatus is detected by the data detecting means. The secret information decoding / reproducing apparatus according to claim 1,
The secret information decoding / reproducing apparatus, wherein the secret information storage means is an external storage device in which encrypted information is written as secret information. The secret information decoding / reproducing apparatus according to claim 1,
The confidential information decryption / playback apparatus further includes decryption key storage means,
The decryption key storage means includes a decryption key extracted by the decryption key extraction means, and specific information for specifying confidential information stored in the confidential information storage means that can be decrypted by the decryption key. , Remember to associate with each other,
The secret information decoding means stores secret information specified by the specific information stored in the decryption key storage means among the secret information stored in the secret information storage means in the decryption key storage means. A secret information decryption / playback apparatus, wherein decryption is performed using a stored decryption key. In the secret information decoding / reproducing apparatus according to any one of claims 1 to 4,
The secret information specifying means specifies secret information stored in the secret information storage means to be decoded by video / audio information identification information included in data detected by the data detection means. Secret information decoding and reproducing apparatus. In the secret information decoding / reproducing apparatus according to any one of claims 1 to 4,
The confidential information specifying unit is configured to perform decoding based on transmission source identification information included in the data detected by the data detection unit and timing at which data including the transmission source identification information is detected by the data detection unit. A secret information decoding / reproducing apparatus characterized by identifying secret information stored in the secret information storage means to be performed. In the confidential information decoding / reproducing apparatus according to any one of claims 1 to 6,
The secret information decrypting means includes the decryption key extracted by the decryption key extracting means with the secret information specified by the secret information specifying means out of the secret information stored in the secret information storage means. A secret information decryption / reproduction device, wherein decryption is performed using a second decryption key stored in an external memory device. The secret information decoding / reproducing apparatus according to claim 7,
The second decryption key is a key used to identify whether the viewer or the secret information decoding / playback apparatus has a right to decrypt the secret information specified by the secret information specifying means. When the viewer or the secret information decryption / reproduction device has the right, the secret information specifying means identifies the decryption key extracted by the decryption key extraction means and the second decryption key. A secret information decoding / reproducing apparatus, wherein the secret information can be correctly decoded. The secret information decoding / reproducing apparatus according to claim 8,
The secret information stored in the secret information storage means is encrypted by an individual encryption key that is different for each viewer or secret information decoding / playback device and a common encryption key common to all viewers or all secret information decryption / playback devices. A secret information decoding / reproducing apparatus, characterized in that In the confidential information decoding / reproducing apparatus according to any one of claims 1 to 6,
The decryption key extracted by the decryption key extraction means is encrypted,
The secret information decrypting means decrypts the decryption key extracted by the decryption key extracting means with the second decryption key stored in the external memory device, and the decrypted decryption key A secret information decoding / reproducing apparatus for decoding secret information specified by the secret information specifying means among the secret information stored in the secret information storage means. The secret information decoding / reproducing apparatus according to claim 10,
The second decryption key is a key used to identify whether the viewer or the secret information decoding / playback apparatus has a right to decrypt the secret information specified by the secret information specifying means. When the viewer or the secret information decryption / playback apparatus has the right, the decryption key extracted by the decryption key extraction means can be correctly decrypted by the second decryption key. A secret information decoding / reproducing apparatus. In the confidential information decoding / reproducing apparatus according to any one of claims 1 to 6,
The secret information decryption / playback apparatus further includes an encryption key detection unit and an encryption key storage unit,
The secret information stored in the secret information storage means is encrypted with the first encryption key,
The encryption key detecting means is configured to encrypt the first encryption key using a second encryption key and a third encryption key and transmit the encrypted key superimposed on the video / audio information. Detect information,
The encryption key storage means stores the encryption key information detected by the encryption key detection means in association with the confidential information stored in the confidential information storage means;
The decryption key extracting means extracts the third encryption key as a decryption key for decrypting the secret information specified by the secret information specifying means;
The secret information decrypting means includes a third encryption key extracted by the decryption key extracting means and a second decryption that is stored in the external memory device and is different for each viewer or secret information decrypting / reproducing device. The key is used to decrypt the encryption key information stored in the encryption key storage means, extract the first encryption key, and use the extracted first encryption key as a decryption key. A secret information decoding / reproducing apparatus, wherein the secret information specified by the secret information specifying means is decoded. In the confidential information decoding / reproducing apparatus according to any one of claims 1 to 6,
The secret information decryption / playback apparatus further includes an encryption key detection unit and an encryption key storage unit,
The secret information stored in the secret information storage means is encrypted with the first encryption key,
The encryption key detecting means encrypts the video and audio data by encrypting the first encryption key with a third encryption key and further encrypting the encrypted information with a second encryption key. Detect the encryption key information sent superimposed on the information,
The encryption key storage means uses the second decryption key in which the encryption key information detected by the encryption key detection means is stored in the external memory device and is different for each viewer or secret information decryption / reproduction device. Storing the decrypted encryption key information in association with the secret information stored in the secret information storage means,
The decryption key extracting means extracts the third encryption key as a decryption key for decrypting the secret information specified by the secret information specifying means;
The secret information decryption means decrypts the encryption key information stored in the encryption key storage means with the third encryption key extracted by the decryption key extraction means, and A secret information decoding / reproducing apparatus characterized by extracting a secret key and decrypting secret information specified by the secret information specifying means using the extracted first encryption key as a decryption key. The secret information decoding / reproducing apparatus according to claim 12 or 13,
The first encryption key is common to all viewers or all secret information decryption / playback devices, and the second encryption key is different for each viewer or secret information decryption / playback device, The secret information decoding / reproducing apparatus, wherein the third encryption key is common to all viewers or all secret information decoding / reproducing apparatuses. A video / audio information receiving step of receiving video / audio information which is video information or audio information transmitted from a transmission source;
A video / audio information reproducing step for reproducing the video / audio information received in the video / audio information receiving step;
A data detection step of detecting data superimposed on the video and audio information;
Concealment that specifies confidential information to be decoded out of confidential information stored in confidential information storage means for storing encrypted information as confidential information based on information included in the data detected in this data detection step An information identification step;
A decryption key extracting step for extracting a decryption key for decrypting the secret information specified in the secret information specifying step from information included in the data detected in the data detection step;
Of the secret information stored in the secret information storage means, the secret information decrypting step for decrypting the secret information identified in the secret information identifying step with the decryption key extracted in the decryption key extracting step;
A secret information reproduction step for reproducing the secret information decrypted in the secret information decryption step;
A method for decrypting and reproducing confidential information, comprising:

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