JP2005184524A - Electronic mail delivery system utilizing electronic watermark - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electronic mail delivery system utilizing an electronic watermark with which the user of a specific mail address can obtain reproduction history so that a purchaser does not recognize it when the purchaser reproduces contents. <P>SOLUTION: When a content delivery site 1 transmits contents ai desired by a user terminal 2 (player apparatus), a secret mail address bi is embedded in a predetermined field of the contents ai by electronic watermarking and the contents are thereafter transmitted via a communication network 3. When content information Ai with the mail address is received at the side of the user terminal 2, the user terminal 2 transmits mail of reproduction history information of a user (purchaser) destined to the specific mail address bi to a mail server 4. For example, the number of times of reproducing the contents, a reproducing time, an operational environment for reproduction, and the like are transmitted. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an electronic mail distribution system, and more particularly, to electronically notify a user of information related to a content reproduction history of a user terminal, which is a content purchaser (user), using a digital watermark to a specific mail address. The present invention relates to an electronic mail system using a watermark.

  In the case where a URL is attached to the content and the mail address is described in a form in the Web site of this URL, mail can be transmitted to this mail address.

  For example, when accessing the URL of a popular artist, if the page contains an e-mail address for accepting e-mail to the artist, the user writes his / her e-mail address and sends an e-mail to that e-mail address. There are services that can be sent.

  On the other hand, a service has been proposed that incorporates a digital watermark into content and uses it to link to the content.

  For example, Japanese Patent Application Laid-Open No. 9-128408 (Patent Document 1) provides a description that refers to external information via video information or a network on an optical disc.

  Japanese Patent Laid-Open No. 9-247599 (Patent Document 2) provides a description that refers to multimedia data recorded on an optical disc and multimedia data recorded on an Internet server.

  Furthermore, Japanese translations of PCT publication No. 2002-544627 (patent document 3) can start the automated transaction relevant to a content by using the digital watermark incorporated in the media content, and has information and a transaction. You can link creative content.

  However, the content distribution side has notified the predetermined e-mail address to the liner notes bundled with the content, the content distribution side site on the Web, etc., and the user can send an e-mail to that address. A mail address has to be input directly from the mailer (it has to be sent spontaneously), which has been a problem for the user.

  In addition, an e-mail can be transmitted by a form in a Web site from a URL attached to the content, but this must be voluntarily transmitted with an e-mail address.

  In addition, in the case of an e-mail address that the user wants to keep secret, there is a problem that it is difficult for the user to send it without being known.

  The present invention has been made to solve the above problems. When a user who is a content purchaser uses or plays back content, the playback history is automatically addressed to a specific mail address without the user being aware of it. An object of the present invention is to obtain an e-mail distribution system using a digital watermark that can obtain reproduction history information so that a user of a specific e-mail address does not know a purchaser by transmitting.

  In the first aspect, when the distribution server transmits content data to the user terminal, content information with a mail address in which a specific mail address is embedded in the content data with a digital watermark is generated, and the user is transmitted via a communication network. An e-mail distribution system using a digital watermark that transmits to a terminal and transmits predetermined data related to reproduction of the content data from the user terminal to the specific e-mail address via the communication network. The server stores a first file in which the content name is associated with the content data, and a second file in which the content name is associated with one or a plurality of specific mail addresses. A content file of the content name from the file and the first file. Means for reading the content data corresponding to the content name from the first file, and reading the specific mail address corresponding to the content name from the second file, Means for generating content information with a mail address embedded in a predetermined field of the read content data by performing digital watermark processing and transmitting the content information to the user terminal via the communication network.

  The user terminal receives the content information with the mail address from the distribution server, stores the content information in a third file, and the specific field from the predetermined field of the content data of the content information with the mail address Means for reading the e-mail address, and means for obtaining the predetermined data relating to the reproduction of the content data in accordance with a reproduction instruction for the content data and transmitting the predetermined data to the read specific e-mail address And the summary.

  According to a second aspect of the present invention, when the distribution server transmits content data to the user terminal, content information with a mail address is generated by encrypting a specific mail address in the content data and embedding it with a digital watermark, via a communication network. E-mail delivery that transmits to the user terminal, decrypts the specific e-mail address at the user terminal, and transmits predetermined data relating to reproduction of the content data to the specific e-mail address via the communication network System.

  The distribution server stores a first file in which the content name and the content data are stored in association with each other, and a first file in which the content name is associated with one or many specific mail addresses. 2 and a means for reading the content data corresponding to the content name from the first file when transmitting the content data of the content name from the first file to the user terminal; When transmitting the content data with the content name from the file to the user terminal, the specific mail address corresponding to the content name is read, the specific mail address is encrypted with a random number, and the encrypted specific Means for generating a decryption key for decrypting the e-mail address; and A specific mail address and the decryption key the encrypted in the field of Tsudeta embedded by performing an electronic watermark process, and means for transmitting to the user terminal so as the email address with the content information.

  The user terminal receives the content information with the mail address from the distribution server, stores the content information in a third file, and the encryption from the predetermined field of the content data of the content information with the mail address. Means for reading the specified specific mail address and decryption key, means for decrypting the read specific mail address encrypted with the decryption key, and accompanying the reproduction instruction for the content data, The gist of the present invention is to obtain data related to the reproduction of the content data and to transmit the data to the decrypted specific mail address.

According to a third aspect of the present invention, when the distribution server transmits content data to the user terminal, content information with a mail address is generated by subdividing a specific mail address and embedding it in a predetermined field of the content data with a digital watermark. Transmitting to the user terminal via a communication network, combining and restoring the specific mail address at the user terminal, and sending predetermined data related to reproduction of the content data to the restored specific mail address An e-mail delivery system for sending via a communication network,
The distribution server stores a first file in which the content name and the content data are stored in association with each other, and a first file in which the content name is associated with one or many specific mail addresses. Means for sequentially reading out the content data corresponding to the content name from the first file in units of a predetermined block when transmitting the content data of the content name from the second file and the first file to the user terminal Reading the specific e-mail address corresponding to the content name, obtaining address data obtained by subdividing the specific e-mail address, and content in the last block unit in the read block-unit content data In the predetermined field of data, one of the subdivided address data is stored. Is embedded by performing digital watermark processing, and the remaining address data of the remaining fragmented address data is embedded by applying digital watermark processing to a predetermined field of the remaining content data in block units, and is embedded in the mail. Means for causing the user terminal to transmit the addressed content information.

  The user terminal receives the content information with the mail address from the distribution server, stores the content information in a third file, and the mail address having the content name of the content data of the content information with the mail address Means for sequentially reading the content data of each block of the attached content data information, and each time the content data of the block is read, the subdivided address data exists in the predetermined field of the content data of the block A means for reading out the data, a means for combining the read-out fragmented address data in accordance with a pre-stored combination condition, and restoring the original specific mail address; and the content name To playback instructions for content data I, the calculated data relating to reproduction of the content data, and summarized in that the data and means for transmitting to said restored original specific mail address.

  As described above, according to the present invention, when content is transmitted to the user terminal via the communication network, the distribution server embeds a specific mail address (one or more) in the content data with a digital watermark. The content information with the mail address is transmitted to the user terminal via the communication network, and the data related to the reproduction of the content data is transmitted from the user terminal to a specific mail address.

  For this reason, when a user who is a purchaser of content uses or plays back content, the playback history information is stored so that the purchaser does not know the specific email address and the purchaser does not know the user of the specific email address. The effect that it can be obtained is acquired.

  In addition, since the specific mail address is encrypted and watermarked, even if the watermark field can be read on the user terminal side, the purchaser cannot know the specific mail address. Has been obtained.

  Furthermore, the distribution server side blocks the content data to be transmitted to the user side with a predetermined length, subdivides a specific mail address corresponding to the content data, and sets the address data of the subdivided mail address as The predetermined fields of the block-based content block are scattered, and these fields are digitally watermarked and transmitted to the user terminal.

  For this reason, unless all the content blocks are reproduced on the user side, data is not transmitted from the user terminal to a specific mail address. In other words, even if it is desired to automatically send some information from a user terminal to a specific mail address, if all content blocks are not played back, a specific mail address is not generated, and therefore the effect of prompting the playback of content data is promoted. Has been obtained.

<Embodiment 1>
FIG. 1 is a schematic configuration diagram of an electronic mail distribution system using the digital watermark according to the first embodiment. In the distribution system shown in FIG. 1, when the content distribution site 1 transmits the content ai desired by the user terminal 2 (player device), a secret mail address bi (referred to as a specific mail address) is stored in a predetermined field of the content ai. Is embedded with a digital watermark and transmitted via the communication network 3, and when the user terminal 2 receives the above-mentioned content information Ai with a mail address, the user (purchaser) 's reproduction history information mail is sent to a specific mail address bi. To the mail server 4. For example, the number of times of content playback, playback time, operating environment at the time of playback, and the like are transmitted.

  As shown in FIG. 1, the content distribution site 1 includes a Web server 5, a content database 8, a mail address database 9, and a content distribution server 10. The digital watermark embedding function may be implemented by the Web server 5 or the content distribution server 10 (also collectively referred to as a distribution server), but is provided in the content distribution server 10 in the present embodiment.

  The content database 8 stores various content information (content name, content data, artist name, etc.).

  In the mail address database 9, the content name and the mail address of the specific mail address bi are linked and stored.

  The content distribution server 10 includes a content reading unit 12 and a watermark embedding unit 13.

  The content reading unit 12 extracts content data ai corresponding to the content name ei from the user terminal 2 from the content database 8.

  The watermark embedding unit 13 searches the mail address database 9 for a specific mail address bi corresponding to the content name ei, and embeds the searched specific mail address bi in a predetermined field of the content data ai with a digital watermark. The content information with address Ai is transmitted via the Web server 5.

  On the other hand, the user terminal 2 includes a content reproduction unit 20, a watermark reading unit 21, a history information calculation unit 23, an automatic mail transmission unit 22, and the like, and the content Ai with a mail address from the content distribution site 1 is stored in the memory 24. to download.

  When the content information Ai with the mail address is stored in the memory 24, the watermark reading unit 21 searches a predetermined field of the content data ai to determine whether or not the electronic watermark mail address is embedded. If it is, the history information calculation unit 23 is activated and the electronic watermark mail address is read and sent to the automatic mail transmission unit 22. The content playback unit 20 plays back the content data ai in the memory 24.

  The history information calculation unit 23 counts the number of times the content is reproduced or measures the reproduction time or reads the operation environment (volume, presence of headphones, etc.) at the time of reproduction, and transmits the reproduction history information to the automatic mail transmission unit 22.

  The automatic mail transmission unit 22 transmits the reproduction history information to the mail server 4 to the read mail address.

  The operation of the first embodiment configured as described above will be described with reference to the sequence diagram of FIG.

  The user (content purchaser) operates the user terminal 2 to input and access the URL of the content distribution site 1 (d1).

  The web server of the content distribution site 1 transmits a page for inputting a name, ID code, content name, and the like to the user terminal 2 via the communication network 3 (d2).

  The user inputs predetermined data to this page according to the input form and transmits it to the content distribution site 1 (referred to as content request information) (d3).

  The content distribution server 10 of the content distribution site 1 receives the content request information (content name, ID, e-mail address, etc.) and authenticates it by comparing it with previously stored member information (not shown) (d4). The authentication result is transmitted to the user terminal 2 via the communication network 3 (d5).

  Next, the content reading unit 12 reads content data corresponding to the content name of the content request information from the content database 8 (d6).

  Further, the watermark embedding unit 13 searches the mail address database 9 for a specific mail address bi corresponding to the content name, and embeds it in a predetermined field of the content data and performs digital watermark processing (d7). Then, the content information Ai with the mail address is transmitted to the user terminal 2 (d8).

  On the other hand, the user terminal 2 downloads the content information Ai with the mail address to the memory 24 (file) (d9). For example, in the case of music data, the predetermined field of the above-described digital watermark processing is a field having waveform data. In the case of an image, the image is decomposed into frequency components, and a correction signal is added only to a specific band.

  Next, the user of the user terminal 2 displays the content name ei of the content information Ai with the mail address in the memory 24 on the screen, selects a desired content name from this screen, and sends a reproduction instruction. In response to the reproduction instruction, when the content information Ai with the mail address is stored in the memory 24, the watermark reading unit 21 searches a predetermined field of the content data ai, and embeds a specific mail address bi with a digital watermark. If it is embedded, the history information calculation unit 23 is activated and the specific mail address bi is read and sent to the automatic mail transmission unit 22 (d10).

  In addition, the history information calculation unit 23 counts the number of times the content has been played (d11) upon activation, and sends this count value to the automatic mail transmission unit 22 as reproduction history information. The automatic mail transmission unit 22 Count information (content name, user name, number of times of reproduction, etc.) is transmitted to the server 4 to a specific mail address bi (d12, d13). Further, the content reproduction unit 20 reproduces the content data in the memory 24 (d14).

  That is, the content distribution site 1 and the user terminal 2 perform the processing described in the flowchart of FIG.

  The content distribution server 10 embeds a specific mail address bi corresponding to the content name in the content data with a digital watermark (S11), and transmits this content information Ai with a mail address to the user terminal 2 (S12).

  The user terminal 2 reads a predetermined field of the content information Ai with a mail address, and determines whether or not a mail address with a digital watermark is contained (S14).

  If it is determined in step S14 that the electronic mail address is included, the number of times the content is reproduced is counted (S15), and the counted number of reproductions is transmitted to a specific electronic mail address of the electronic watermark. (S16), the content is reproduced (S17).

  In the above embodiment, one mail address is stored in the mail address database corresponding to the content. However, a large number of mail addresses may be linked.

<Embodiment 2>
FIG. 4 is a schematic configuration diagram of an electronic mail distribution system using the digital watermark according to the second embodiment. In the distribution system shown in FIG. 4, when the content distribution site 1 transmits content data ai desired by the user terminal 29 (player device), a specific mail address bi and specific data ci ( The command to send the playback count by e-mail) is embedded with a digital watermark. Then, when the user terminal 2 receives the content information Di with a mail address through the communication network 3 and receives the content information Di with a mail address, the user terminal 2 receives the specific mail address bi and the specific data ci from the content data ai. The information is read, information based on the specific data is obtained, and transmitted to the mail server 4 addressed to a specific mail address. For example, the number of times of content playback, playback time, operating environment at the time of playback, and the like are transmitted.

  4, the content distribution site 1 includes a Web server 5, a content database 8, and a mail address database 9 similar to those in FIG. 1.

  Further, the content distribution server 25 according to the fourth embodiment inputs what data is to be sent to a specific mail address bi, generates a command for obtaining the input data, and generates this command as specific data ci. A specific data embedding unit 27 to be passed to the watermark embedding unit 26 as (number of reproductions or reproduction time) and a specific mail address bi corresponding to the content name read by the content reading unit 12 are read from the mail address database 9 and specified. In addition to the data ci, a watermark embedding unit 26 for embedding the content data ai with a watermark is provided.

  On the other hand, the user terminal 29 includes a content reproduction unit 20, a history information calculation unit 23, an automatic mail transmission unit 22, a memory 24 in which content Di with a mail address from the content distribution site 1 is downloaded, and the like. I have.

  Also in the second embodiment, the user operates the user terminal 29 to display the content name in the memory 24 on the screen and selects the desired content. A reproduction instruction is sent out by this selection. Next, in response to the reproduction instruction, the watermark reading unit 30 searches the memory 24 for a predetermined field of the content data ai of the content Di with the mail address, and determines whether the electronic watermark mail address and the specific data are embedded. If it is embedded, the history information calculation unit 23 is activated to pass the specific data, and the electronic watermark mail address is read and sent to the mail automatic transmission unit 22.

  The operation of the distribution system according to the second embodiment configured as described above will be described with reference to the sequence diagram of FIG.

  The user (content purchaser) operates the user terminal 29 to input and access the URL of the content distribution site 1 (d1).

  The web server of the content distribution site 1 transmits a page for inputting a name, ID code, content name, and the like to the user terminal 29 via the communication network 3 (d2).

  The user inputs predetermined data to this page according to the input form and transmits it to the content distribution site 1 (referred to as content request information) (d3).

  The content distribution server 25 of the content distribution site 1 receives the content request information (content name, ID, e-mail address, etc.) and authenticates it by comparing it with previously stored member information (not shown) (d4). The authentication result is transmitted to the user terminal 29 via the communication network 3 (d5).

  Next, the content reading unit 12 reads content data ai corresponding to the content name of the content request information from the content database 8 (d6).

  The watermark embedding unit 26 searches the mail address database 9 for the mail address bi corresponding to the content name, and embeds it in the content data (d7). Next, the watermark embedding unit 26 links the specific data from the specific data embedding unit 27 (in this embodiment, a command for obtaining the number of reproductions) to the mail address and embeds it with the watermark (d20).

  Then, this content data (content, mail address, specific data) is transmitted to the user terminal 29 via the Web server (d21).

  On the other hand, the user terminal 29 downloads the content information Di with a mail address to the memory 24 (d9).

  Next, when the content Di with the mail address is stored in the memory 24, the watermark reading unit 30 reads a predetermined field of the content information Di (d10), and whether the specific mail address and the specific data are embedded. If it is embedded, the history information calculation unit 23 is activated to decode the specific data (the number of reproductions), and the calculation of the number of reproductions is passed to the history information calculation unit 23 to determine the number of reproductions. At the same time, the e-mail address is read and sent to the e-mail automatic transmission unit 22 (d22).

  In addition, the history information calculation unit 23 counts the number of times the content has been played (d11) upon activation, and sends this count value to the automatic mail transmission unit 22 as reproduction history information. The automatic mail transmission unit 22 Count information (including content name, user name, etc.) is sent to the server 4 to the mail address bi (d12, d13). Then, the content reproduction unit 20 reproduces the content data in the memory 24 (d14).

  That is, the second embodiment makes it possible to determine what history information is sent to a specific mail address when content is played on the user terminal 29 side on the content distribution site 1 side. The specific data indicating what kind of history information is delayed together with the e-mail address is a digital watermark, so the user does not know.

  Therefore, the content distribution site is not known to the user, and the specific data accompanying the reproduction can be transmitted to the secret mail address led by the content distribution site.

<Embodiment 3>
FIG. 6 is a schematic configuration diagram of an electronic mail delivery system using the digital watermark according to the third embodiment. In the distribution system shown in FIG. 6, when the content distribution site 1 transmits the content data ai desired by the user terminal 35 (player device), the specific mail address bi (secret mail address) is encrypted and decrypted. Generate a key, embed the secret mail address bi and key ei in a predetermined field of the content data ai, and send the digital watermark processing content information Hi to the user terminal 35 via the communication network 3 To do. When the above-mentioned content information Hi is received on the user terminal 35 side, the encrypted specific mail address hi and key ei in a predetermined field of the content information Hi are read and decrypted, and the decrypted specific mail address is The data is decompressed with the decrypted key and transmitted to the mail server 4 to this specific mail address bi. For example, the number of times of content playback, playback time, operating environment at the time of playback, and the like are transmitted.

  6, the content distribution site 1 includes a Web server 5, a content database 8, and a mail address database 9 similar to those in FIG.

  The content distribution server 36 according to the third embodiment includes a content reading unit 12, a watermark embedding unit 37, and an encryption unit 39 similar to those in FIG.

  The content reading unit 12 extracts content data ai corresponding to the content name from the user terminal 2 from the content database 8.

  The encryption unit 39 reads the secret mail address bi corresponding to the content name from the mail address database 9, and encrypts it. This encryption is preferably generated by generating a random random number. In addition, the encryption unit 39 generates a key for decrypting the encrypted specific mail address with the above-described random number.

  The watermark embedding unit 37 embeds the encrypted secret mail address and key in the content information field, performs watermark processing on the field, and transmits the field.

  On the other hand, the user terminal 35 includes a content reproduction unit 20, a history information calculation unit 23, an automatic mail transmission unit 22, and the like similar to those in FIG. In the third embodiment, the watermark reading unit 40 reads the encrypted secret mail address and key in the field of the content information Hi stored in the memory 24.

  The decryption unit 41 decrypts the encrypted secret mail address with the key and outputs it to the automatic mail transmission unit 22 and the history information calculation unit 23.

  The operation of the distribution system according to the third embodiment configured as described above will be described with reference to the sequence diagram of FIG.

  The user (content purchaser) operates the user terminal 35 to input and access the URL of the content distribution site 1 (d1).

  The web server of the content distribution site 1 transmits a page for inputting a name, ID code, content name, and the like to the user terminal 35 via the communication network 3 (d2).

  The user inputs predetermined data to this page according to the input form and transmits it to the content distribution site 1 (referred to as content request information) (d3).

  The content distribution server 36 of the content distribution site 1 receives the content request information (content name, ID, e-mail address, etc.) and authenticates it by comparing it with previously stored member information (not shown) (d4). The authentication result is transmitted to the user terminal 36 via the communication network 3 (d5).

  Next, the content reading unit 12 reads content data corresponding to the content name of the content request information from the content database 8 (d6).

  Next, the encryption unit 39 encrypts the specific mail address bi and generates a decryption key (d25, d26). In this encryption, for example, a random number is generated and added to a specific mail address bi, and the addition result is used as an encrypted specific mail address. This key is obtained by using exclusive OR (inversion of the flagged part) at the time of encryption.

  Next, the watermark embedding unit 37 embeds a key and a specific e-mail address as a set in a predetermined field of the content data, performs a watermark process on this field (d27), and sends it to the user terminal 36 as content information Hi. Transmit (d28).

  On the other hand, the user terminal 36 downloads the content information Hi to the memory 24 (d9).

  Next, when the content with the mail address is stored in the memory 24, the watermark reading unit 40 reads a predetermined field of the content, determines whether or not a specific mail address and key are embedded, and is embedded. If so, the specific mail address and key are read (d10).

  Next, the decryption unit 41 decrypts the specific mail address encrypted using this key, and outputs it to the history information calculation unit 23 and the automatic mail transmission unit 22 (d28).

  When the secret mail address is output, the history information calculation unit 23 obtains (updates) the number of times the content has been reproduced and outputs it to the automatic mail transmission unit 22 (d11).

  The automatic mail transmission unit 22 transmits the content name, the number of reproductions, and the user name from the history information calculation unit 23 to the secret mail address to the mail server 4 (d12, d13). Then, the content reproduction unit 20 reproduces the content data in the memory 24 (d14).

  That is, the content distribution server 36 and the user terminal 35 of the content distribution site 1 perform the processing described in the flowchart of FIG.

  The content distribution server 36 encrypts the mail address bi corresponding to the content name and generates a key (S21).

  Next, the mail address and key encrypted with the digital watermark are embedded in the content (S22), and the content with the mail address is transmitted to the user terminal 35 (S23).

  On the other hand, the user terminal 35 reads a predetermined field subjected to digital watermark processing of the content with the mail address (S24), and determines whether or not the encrypted mail address and key are contained (S25).

  When it is determined in step S25 that the encrypted specific mail address and key are contained, the specific mail address encrypted with this key is decrypted (S26), and the content addressed to this mail address is decrypted. After the number of reproductions is transmitted to the mail server 4 (S27), the content is reproduced (S28).

  Therefore, the user of the user terminal cannot easily read a specific mail address.

<Embodiment 4>
FIG. 9 is a schematic configuration diagram of an electronic mail delivery system using the digital watermark according to the fourth embodiment. When the content distribution site 1 transmits the content data ai desired by the user terminal 55 (player device), the distribution system shown in FIG. 9 subdivides a specific mail address bi (secret mail address) and separates it. The content information Fi embedded in a predetermined field of the blocked content data ai and subjected to the watermark processing is transmitted to the user terminal 55 via the communication network 3. When the above-mentioned content information Fi is received on the user terminal 55 side, the disparate data in a predetermined field of the content information Fi is read and combined according to a predetermined condition to obtain the original specific mail address.

  And it transmits to the mail server 4 addressed to this specific mail address bi. For example, the number of times of content playback, playback time, operating environment at the time of playback, etc. are transmitted.

  9, the content distribution site 1 includes a Web server 5, a content database 8, and a mail address database 9 similar to those in FIG. 1.

The content distribution server 50 according to the fourth embodiment has the content reading unit 12 similar to that in FIG. 1. The subdivision unit 51 is a specific mail address bi linked to the content name from the user terminal 55. Are extracted from the mail address database 9, and are subdivided according to predetermined conditions, and further separated. Further, since the subdivision unit 51 knows how the pieces are separated, it is possible to obtain a coupling condition for restoration and embed it in a predetermined field. For example, when the subdivided data is divided into b4, b2, b1, and b3, the condition is defined such that b4 is the last and b1 is the top.

  The watermark embedding unit 52 embeds the data of the separated mail address in a predetermined field of the content data blocked by the content blocking unit 53, performs digital watermark processing, and transmits this to the user terminal 55. This embedding is performed by embedding the subdivided data (specific mail address) in the final block, and the subsequent data is preferably dispersed in an appropriate block, and the coupling conditions are preferably dispersed.

  The content blocking unit 53 blocks the content data ai read by the content reading unit 12 for each bar, for example.

  On the other hand, the user terminal 55 includes a content reproduction unit 20, a history information calculation unit 23, an automatic mail transmission unit 22, and the like similar to those in FIG. In the fourth embodiment, the watermark reading unit 56 reads the data for each block of the content information field stored in the memory 24 and passes the data to the combining unit 57.

  The combining unit 57 combines these data according to a predetermined condition stored in advance, obtains the original secret mail address bi, and passes it to the history information calculation unit 23 and the automatic mail transmission unit 22.

  The operation of the distribution system of the fourth embodiment configured as described above will be described using the sequence diagram of FIG.

  The user (content purchaser) operates the user terminal 55 to input and access the URL of the content distribution site 1 (d1).

  The web server of the content distribution site 1 transmits a page for inputting a name, an ID code, a content name, and the like to the user terminal 55 via the communication network 3 (d2).

  The user inputs predetermined data to this page according to the input form and transmits it to the content distribution site 1 (referred to as content request information) (d3).

  The content distribution server 50 of the content distribution site 1 receives the content request information (content name, ID, e-mail address, etc.) and authenticates it by comparing it with previously stored member information (not shown) (d4). The authentication result is transmitted to the user terminal 55 via the communication network 3 (d5).

  Next, the content reading unit 12 reads content data corresponding to the content name of the content request information from the content database 8 (d6).

  Then, the content blocking unit 53 divides the content data ai into blocks as shown in FIG. 11A (d29).

  Next, as shown in FIG. 11B, the subdividing unit 51 subdivides a specific mail address bi according to a predetermined condition (d30), and separates this data (d31). For example, in the case of a specific mail address as shown in FIG. 11A, each of the ranges b1, b2, b3, and b4 is set as one data.

  Then, the watermark embedding unit 52 sequentially embeds discrete data and combination conditions as shown in FIG. 11C in a predetermined field of the blocked content data (only when the combination conditions are transmitted from the distribution side), Digital watermark processing is performed (d32), and as shown in FIG. 11 (d), it is transmitted to the user terminal 55 as content information Fi with different mail addresses (d33). At this time, when there is no combination condition on the user terminal side, it is preferable to attach a condition for returning to the original with a digital watermark. In addition, it is preferable that embedding is performed by embedding the subdivided data (specific mail address) in the final block, and the subsequent data is dispersed in an appropriate block.

  On the other hand, the user terminal 55 downloads the content information Fi with different mail addresses to the memory 24 (d9).

  Next, when the content Fi is stored in the memory 24, the watermark reading unit 56 reads the content data for each block, reads a predetermined field of the content data, and reads one piece of separated data ( d10). Then, the combining unit 57 combines these data with the pre-stored combining condition, restores the original secret mail address, and outputs it to the history information calculating unit 23 and the automatic mail transmitting unit 22 (d34).

  When a specific mail address is output, the history information calculation unit 23 obtains (updates) the number of times the content has been reproduced and outputs it to the automatic mail transmission unit 22 (d11).

  The automatic mail transmission unit 22 transmits the content name, the number of reproductions, and the user name from the history information calculation unit 23 to the secret mail address to the mail server 4 (d12, d13). Then, the content reproduction unit 20 reproduces the content data in the memory 24 (d14).

  That is, the content distribution server 36 and the user terminal 55 of the content distribution site 1 perform the processing described in the flowchart of FIG.

  The content distribution server 56 divides the content data into units of blocks and subdivides the mail addresses bi corresponding to the content names into units of predetermined blocks, and separates them (S31).

  Next, this discrete data is embedded in a predetermined field of the block-unit content data ai, and digital watermark processing is performed (S32). Then, the content information Fi with the different email addresses is transmitted to the user terminal 55 (S33).

  On the other hand, the user terminal 55 reads out the content information with different mail addresses by the watermark reading unit 56 (S34), and determines whether or not the mail addresses with different addresses are contained (S35).

  If it is determined in step S35 that a separate mail address is included, the original secret mail address is obtained by combining these data according to a predetermined condition (combination) (S37). Then, after the content reproduction count is transmitted to the mail address to the mail server (S38), the content is reproduced (S39).

  Therefore, the user of the user terminal cannot send an e-mail to a specific e-mail address unless all of the block-unit content data is reproduced.

1 is a schematic configuration diagram of an electronic mail distribution system using a digital watermark according to Embodiment 1. FIG. FIG. 3 is a sequence diagram for explaining the operation of the first embodiment. 3 is a flowchart illustrating the concept of the first embodiment. 3 is a schematic configuration diagram of an electronic mail distribution system using a digital watermark according to Embodiment 2. FIG. 10 is a sequence diagram for explaining an operation of the second embodiment. FIG. FIG. 10 is a schematic configuration diagram of an electronic mail distribution system using a digital watermark according to a third embodiment. FIG. 10 is a sequence diagram for explaining the operation of the third embodiment. 10 is a flowchart for explaining the concept of the third embodiment. It is a schematic block diagram of the electronic mail delivery system using the electronic watermark of this Embodiment 4. FIG. 10 is a sequence diagram for explaining the operation of the fourth embodiment. FIG. 10 is an explanatory diagram for explaining subdivision and embedding of a specific mail according to a fourth embodiment. 10 is a flowchart for explaining the concept of the third embodiment.

Explanation of symbols

1 Content distribution site 2 User terminal 2
5 Web server 5
DESCRIPTION OF SYMBOLS 10 Content delivery server 12 Content reading part 13 Watermark embedding part 20 Content reproduction part 21 Watermark reading part 22 Mail automatic transmission part 23 History information calculation part

Claims (3)

When the distribution server transmits content data to the user terminal, it generates content information with a mail address in which a specific mail address is embedded in the content data with a digital watermark, and transmits it to the user terminal via a communication network. An e-mail distribution system using a digital watermark that transmits predetermined data related to reproduction of the content data from the user terminal to the specific e-mail address via the communication network,
The distribution server
A first file stored in association with the content name and the content data;
A second file in which the content name is associated with one or a plurality of specific e-mail addresses and stored;
Means for reading out the content data corresponding to the content name from the first file when transmitting the content data of the content name from the first file to the user terminal;
The specific mail address corresponding to the content name is read from the second file, digital watermark processing is performed, and the content information with the mail address embedded in a predetermined field of the read content data is generated. Means for transmitting to the user terminal via the communication network,
The user terminal is
Means for receiving the content information with the mail address from the distribution server and storing the content information in a third file;
Means for reading out the specific mail address from the predetermined field of the content data of the content information with the mail address;
The electronic apparatus further comprises means for obtaining the predetermined data related to the reproduction of the content data in accordance with a reproduction instruction for the content data and transmitting the predetermined data to the read specific mail address. Mail delivery system. When the distribution server transmits the content data to the user terminal, content information with a mail address is generated by encrypting a specific mail address in the content data and embedded with a digital watermark, and transmits the content information to the user terminal via a communication network. An e-mail delivery system for transmitting and decrypting the specific e-mail address at the user terminal and transmitting predetermined data relating to reproduction of the content data to the specific e-mail address via the communication network;
The distribution server
A first file stored in association with the content name and the content data;
A second file in which the content name is associated with one or a plurality of specific e-mail addresses and stored;
Means for reading the content data corresponding to the content name from the first file when transmitting content data of the content name from the first file to the user terminal;
When transmitting the content data of the content name from the first file to the user terminal, the specific mail address corresponding to the content name is read, the specific mail address is encrypted with a random number, and the encryption Means for generating a decryption key for decrypting the converted specific mail address;
Means for embedding the encrypted specific e-mail address and the decryption key in a predetermined field of the read content data by performing digital watermark processing, and transmitting this to the user terminal as content information with the e-mail address And
The user terminal is
Means for receiving the content information with the mail address from the distribution server and storing the content information in a third file;
Means for reading the encrypted specific mail address and decryption key from the predetermined field of the content data of the content information with the mail address;
Means for decrypting the read encrypted specific mail address with the decryption key;
An electronic mail distribution system comprising: means for obtaining data related to reproduction of the content data in accordance with a reproduction instruction for the content data, and transmitting the data to the decrypted specific mail address. When the distribution server transmits content data to the user terminal, a specific mail address is subdivided and content information with a mail address embedded in a predetermined field of the content data with a digital watermark is generated via a communication network. Transmitting to the user terminal, combining and restoring the specific mail address at the user terminal, and transmitting the predetermined data relating to the reproduction of the content data to the restored specific mail address via the communication network An e-mail delivery system for sending,
The distribution server
A first file stored in association with the content name and the content data;
A second file in which the content name is associated with one or a plurality of specific e-mail addresses and stored;
Means for sequentially reading the content data corresponding to the content name from the first file in units of predetermined blocks when transmitting the content data of the content name from the first file to the user terminal;
Means for reading the specific mail address corresponding to the content name and obtaining address data obtained by subdividing the specific mail address;
One of the subdivided address data is embedded in a predetermined field of the final block unit content data in the read block unit content data by performing digital watermark processing, and the remaining subdivision is performed. Means for embedding the remaining address data of the received address data by performing digital watermark processing in a predetermined field of the remaining content data in block units, and transmitting the embedded data to the user terminal as content information with a mail address; Have
The user terminal is
Means for receiving the content information with the mail address from the distribution server and storing the content information in a third file;
Means for sequentially reading out the content data of each block unit of the content data information with the mail address having the content name of the content data of the content information with the mail address;
Means for reading out the subdivided address data in the predetermined field of the block-unit content data each time the block-unit content data is read;
Means for combining the read segmented address data in accordance with a pre-stored combination condition and restoring the original specific mail address;
And a means for obtaining data related to the reproduction of the content data in accordance with a reproduction instruction for the content data with the content name and transmitting the data to the restored original mail address. E-mail distribution system using digital watermark.

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