JP2007058678A - Content recording and reproduction device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve problems of a conventional technique for recording and reproducing a content to and from a medium while considering the copyright protection of the content, in which each recording medium must be provided with different identification information, this forces a user's labor of purchasing and using a recording medium with specially assigned identification information for this technique, and assignment management of identification information must be performed for each recording medium since each recording medium cannot obviously have two or more pieces of identification information in a narrow sense. <P>SOLUTION: In this content recording and reproduction technique, encryption of a content is performed using time information and equipment unique identification information as a key without depending on identification information of a recording medium, whereby the copyright of the content can be protected to prevent illicit copies thereof. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a technique for recording and reproducing content while protecting the copyright of the content.

  Conventionally, as a technology for recording and reproducing content while protecting the copyright of the content, CPPM (Content Protection for Pre-Recorded Media) and CPRM (Content Protection for Recordable Media) ) Is known.

  FIG. 29 is a conceptual diagram for briefly explaining an example of a medium on which content is recorded using the CPPM technology and an example of content copyright protection based on the medium. As shown in FIG. 29 (a), in CPPM, in order to decrypt the content that is encrypted and recorded on the medium, identification information unique to the recording medium called “media ID” is used. With one feature. Specifically, when the content is written on the recording medium A by legitimate means, a device key that is secretly assigned and a key that is a seed of an encryption key generated by the device key management organization In addition to the bundle, the content is encrypted using the media ID: A uniquely assigned to the recording destination medium. That is, at the time of reproducing this content, the encrypted content recorded on the recording medium cannot be decrypted unless this media ID: A is used.

Therefore, as shown in FIG. 29 (b), the encrypted content recorded on the recording medium A is illegally copied (bit-by-bit transfer) to another recording medium B (media ID: B). However, since the media IDs necessary for decrypting the encrypted content are different, it cannot be correctly decrypted and cannot be reproduced. The next-generation DVD standard also employs a method of preventing unauthorized copying of content and controlling the number of copies, as described above, by providing identification information unique to the recording medium.
Toshiba Review Vol. 56 No. 7 “Content protection technology for DVD-Audio”

  However, the above conventional technique has a problem that it is necessary to prepare recording media each having different identification information (media ID). This requires the user to purchase and use a recording medium to which identification information is specifically assigned for these technologies. Strictly speaking, since the identification information of the recording medium should not have two or more of the same identification information, it is necessary to perform management for uniquely assigning the identification information for each recording medium.

  In order to solve the above problems, the present invention encrypts content using time information and device-specific identification information as a key without depending on the identification information of the recording medium, thereby protecting the copyright of the content. Provide content recording and playback technology that can protect and prevent unauthorized copying. Specifically, a recording command acquisition unit that acquires a plurality of types of recording commands, a content acquisition unit that acquires content, a holding unit that holds device unique identification information, a time information output unit that outputs time information, The content recording / reproducing apparatus further includes a new writing unit and a copy writing unit.

  Then, when the recording command acquired by the recording command acquisition unit is a “new recording command”, the “new writing unit” is based on the device unique identification information and the time information at the recording command acquisition timing. The encrypted content is generated from the acquired content using the encrypted key, and the generated encrypted content is associated with the time information at the recording command acquisition timing and written to the medium. "Recording part" is a copy recording command acquisition timing when the recording command acquired by the recording command acquisition part is a "copy recording command" of the encrypted content written in the past by the new writing part. It has a function of updating the time information associated with the encrypted content to be copied with the time information and copying and writing the encrypted content to be copied to the medium.

  With the present invention having the above-described configuration, the copyright of content is protected and unauthorized copying can be performed by using device-specific identification information and time information indicating the acquisition timing of a recording command without depending on the recording medium identification information. It is possible to prevent. Therefore, it is possible for the user to save the trouble of purchasing a recording medium to which identification information is specifically assigned for these techniques. In addition, there is no need to perform management of identification information allocation of recording media, and therefore there is an effect that no management cost is generated and there is no occurrence of a situation such as exhaustion of identification information.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to these embodiments, and can be implemented in various modes without departing from the spirit of the present invention. In the first embodiment, claims 1 and 4 will be mainly described. In the second embodiment, claims 2 and 5 will be mainly described. In the third embodiment, claims 3 and 6 will be mainly described.

  Embodiment 1 <Outline of Embodiment 1> FIG. 1 is a conceptual diagram for explaining an example of writing, copying, and playback of content on a recording medium by the content recording / playback apparatus of the present embodiment. . As shown in FIG. 1A, for example, a special television program of a professional baseball Japan series for a certain year is recorded on a DVD medium (recording medium) A using the content recording / reproducing apparatus of the present embodiment. At this time, in this content recording / reproducing apparatus, first, video data of a special program of the Japanese series is added to the secret device unique identification information of the recording / reproducing apparatus, and the writing time of the content, for example, “April 5, 19:30” Is also encrypted using the time information and recorded on the recording medium A.

  Since the encrypted content recorded on the DVD medium A includes time information written on the recording medium as additional information, the time information of the additional information and the content recording / reproduction are reproduced when the content is reproduced. For example, the device-specific identification information secretly held in the device is used to decrypt the encrypted content and reproduce the video.

  On the other hand, as shown in FIG. 1B, when the Japanese series broadcast data recorded on the DVD medium A is copied to another DVD medium B, the encrypted content copied to the DVD medium B is copied. Is updated to the date and time of copying, for example, “April 9, 2005, 10:00”. That is, even if it is attempted to reproduce the data of a special feature program of the Japanese series recorded on the DVD medium B, the time information is different, so that it cannot be correctly decoded and cannot be reproduced.

    <Configuration of First Embodiment> FIGS. 2 and 3 are diagrams illustrating an example of functional blocks in the content recording / playback apparatus according to the present embodiment. As shown in this figure, the “content recording / playback apparatus” (0200, 0300) of this embodiment includes a “recording command acquisition unit” (0201, 0301), a “content acquisition unit” (0202, 0302), “ A "holding unit" (0203, 0303), a "time information output unit" (0204, 0304), a "new writing unit" (0205, 0305), and a "copy writing unit" (0206, 0306). Have. Note that the arrows in FIG. 2 represent an example of the flow of information when content is newly written to the recording medium. The arrows in FIG. 3 represent an example of information flow at the time of content copy writing on a recording medium.

  Further, the functional blocks of the apparatus described below can be realized as hardware, software, or both hardware and software. Specifically, if a computer is used, a CPU, a main memory, a bus, a storage device such as a hard disk or a non-volatile memory, an optical storage medium, a read drive for these media, various communication and printing devices Examples include hardware components such as transmission / reception ports and other peripheral devices, driver programs and other application programs for controlling the hardware, and interfaces used for information input. In addition, these hardware and software can be used to sequentially process the programs developed on the memory with the CPU, process and store data stored on the memory and hard disk, and data input via the interface. This is used for output processing or for controlling each hardware component.

  The present invention can be realized not only as an apparatus but also as a method. A part of the invention can be configured as software. Furthermore, a software product used for causing a computer to execute such software and a recording medium in which the product is fixed to a recording medium are naturally included in the technical scope of the present invention (the same applies throughout the present specification). Is).

  The “recording command acquisition unit” (0201, 0301) has a function of acquiring a plurality of types of recording commands. For example, the recording command acquisition unit may acquire a recording command input by an operation using an operation panel or a remote control button provided on the device, a keyboard or a mouse, or an operation via a graphical interface displayed on the display. “Recording command” is to record content on a recording medium such as various DVDs and CDs, an optical recording medium based on the next-generation DVD standard, a magnetic recording device such as a hard disk drive, or a nonvolatile semiconductor memory. An instruction for.

  Examples of the type of the recording command include “new recording command” and “copy recording command”. FIG. 4 is a diagram for explaining an example of a “new recording command” acquired by the recording command acquisition unit. As shown in this figure, the new recording command includes, for example, a command for newly writing a broadcast program (content) α received by a built-in tuner of the content recording / playback apparatus to a recording medium. The command can be acquired by, for example, acquiring the command by pressing the recording button β of the remote control device and receiving a signal indicating the new recording command by infrared rays in the content recording device.

  FIG. 5 is a diagram for explaining an example of a “copy recording command” acquired by the recording command acquisition unit. As shown in this figure, the copy recording command is a command for copying and recording the content α once recorded on the recording medium A to another recording medium B, for example. For example, the acquisition may be performed by selecting and clicking the copy start button β of the graphical interface displayed on the display with a keyboard or a mouse.

  In addition, as a type of the recording command, there is a “moving recording command” for deleting the content in the copy source recording medium and moving to another recording medium for recording. The movement recording command and the content movement recording process by acquiring the movement acquisition command will be described in the second embodiment.

  As described above, the content recording / playback apparatus of the present invention obtains the recording commands by dividing them into a plurality of types according to the recording characteristics. The copyright of the content can be protected by changing the time information recorded on the recording medium in accordance with the type of the recording command. The “copy recording command” and the “moving recording command” to be described later are obtained in association with information indicating the number of times of copying or moving and information indicating the number of times the copying / moving recording is permitted. The time information to be recorded may not be changed within the permitted number of times range.

  The “content acquisition unit” (0202, 0302) has a function of acquiring content. “Content” refers to data indicating a copyrighted work, such as video, music, images, text, data indicating a computer program, or a combination thereof. The content acquisition unit is, for example, a television broadcast wave reception tuner and encoder, and may acquire content for new writing to a recording medium. Alternatively, it may be obtained by reading an unencrypted / encrypted content recorded on a recording medium, which is a reading drive of an optical recording medium that is a recording medium. In addition, the content acquisition by the content acquisition unit may be various, for example, reading of an image or text by a scanner, acquisition of distribution video / music via a network, and the like.

  The “holding unit” (0203, 0303) has a function of holding device unique identification information. “Device-specific identification information” refers to identification information uniquely assigned to identify the content recording / playback apparatus of the present invention which is a device. For example, in addition to identification information assigned to each device for encryption, For example, the serial number of the device or the IP address of the network compatible device. Alternatively, the device unique identification information may be held as a plurality of bundles in one device. In that case, in content encryption using an encryption key based on device unique identification information described later, for example, a configuration may be adopted in which separate device unique identification information is used for each content.

  Further, this holding unit may be provided in a B-CAS (registered trademark) card used for digital broadcasting or the like inserted in the content recording / reproducing apparatus. In this case, the identification information attached to the B-CAS card corresponds to the device-specific identification information referred to in the present invention, and the component part of the B-CAS card that holds this corresponds to the holding part. When the content recording / playback apparatus is configured by recording / playback software, the device-specific identification information may be software identification information attached to the recording / playback software. In this case, the device unique identification information is copied from the recording / reproducing software and held in the memory of the recording / reproducing apparatus. This memory corresponds to the holding unit in the present invention.

  The holding unit can be realized by a hard disk drive or a nonvolatile memory built in the device, or a medium such as a card as described above and a reading device thereof. Then, by encrypting the content using the device unique identification information held in the holding unit and recording it on the recording medium, it is possible to limit the reproducible devices of the content recorded on the recording medium, and The copyright protection function can be strengthened. Details of the content reproduction (decryption) processing based on the device unique identification information will be described in the third embodiment.

  The “time information output unit” (0204, 0304) has a function of outputting time information. “Time information” refers to time information indicated by year, month, day, hour, minute, second, and the like. For example, information indicated by an enumeration of numbers such as “20050809165532” or “August 9, 2005” Time information including 2-byte full-width character information such as “16:55:32”. This time information may be obtained and output from a digital calendar or a digital clock built in the device.

  The content recording / playback apparatus according to the present embodiment is characterized in that the content is encrypted as described later using an encryption key based on this time information. In other words, copyright infringement due to unauthorized duplication of content can be prevented by the time information. Therefore, it is necessary that this time information is not easily altered. Therefore, for example, the content recording / playback apparatus of the present invention preferably includes a hardware built-in clock that cannot be changed by software processing. Alternatively, for example, it is desirable to perform processing such as periodically setting the internal clock using the NTP (Network Time Protocol).

  The “new writing unit” (0205, 0305), when the recording command acquired by the recording command acquisition unit is a “new recording command”, device-specific identification information, time information at the recording command acquisition timing, The encrypted content is generated from the acquired content using the encryption key based on the above, and the generated encrypted content and the time information at the recording command acquisition timing are associated and written to the medium. The device unique identification information used for content encryption at the time of the new writing process is preferably held in a secret state where the information cannot be peeped. Alternatively, in addition to the device unique identification information and time information, the encryption strength of the encrypted content can be reduced by holding it in a secret state where a secret encryption key cannot be peeked separately and using it for content encryption. It may be guaranteed.

  “Recording command acquisition timing” refers to the recording command acquisition unit, for example, the timing when the recording button of the remote control is pressed, etc. It may be timing. In this way, it is possible to prevent the user from easily confirming the time information at the recording command acquisition timing, which is one of the encryption keys. The time information recorded in association with the encrypted content on the recording medium is recorded as file system information, and may be recorded in a state that can be generally confirmed by the user, or may be encrypted. . Alternatively, it may not be read by a general process, but may be recorded in a form that cannot be easily confirmed by the user, such as being recorded in a secretly accessible area only at the time of decryption described later. In that case, in relation to the time information recorded on the recording medium, information indicating an area determined to be accessible only at the time of decoding may be written on the recording medium.

  FIG. 6 is a conceptual diagram for explaining an example of a process for recording content on a recording medium in the new writing unit. As shown in this figure, first, in the recording command acquisition unit, for example, a “new recording command” is acquired by a remote control operation or the like. Then, for example, a process of encrypting the broadcast program “Japan Series” which is the content received and acquired by the reception tuner which is a content acquisition unit is first performed. In the encryption process, the device unique identification information “1111-xxx” held in the holding unit and the time “April” when the recording button of the remote control, for example, output from the time information output unit is pressed. On the 5th, 19:30 ", an encryption key is generated, and content encryption processing is performed using the encryption key.

  In addition, as an encryption method, for example, there is a method in which device unique identification information and time information are substituted into a one-way function to generate an encryption key. In addition, for example, the content may be encrypted using a key based on the device unique identification information, and the key of the device unique identification information may be encrypted based on the time information. Conversely, the content may be encrypted with a key based on time information, and the key based on the time information may be encrypted with an encryption key based on device unique identification information. Of course, in addition to these pieces of information, for example, a license encryption key distributed individually from a content manager or the like may be added to perform the above encryption processing. Then, the time information “April 5, 19:30” is added as additional information to the content encrypted in this way, and writing processing to the recording medium is performed.

  FIG. 7 is a conceptual diagram for explaining an example of the encryption process in the new writing / recording process. As shown in this figure, an encryption key is generated from the time information and the device unique identification information by a one-way function. The content is encrypted with the encryption key. Of course, the encryption strength may be further increased by preparing an encryption key in addition to the time information and the device unique identification information. Further, the content may be divided into a plurality of pieces, and the encryption process may be performed by changing the encryption key based on the device unique identification information and the time information for each divided content.

  FIG. 8 is a schematic diagram illustrating an example of a hardware configuration in the content recording / playback apparatus of the present embodiment. The operation of each hardware component in the new content writing process on the recording medium will be described with reference to FIG. As shown in this figure, the content recording / playback apparatus includes “CPU (central processing unit)” (0801), “main memory” (0802), “writing device” (0807) as new writing units. It is equipped with. In addition, the “storage device (or storage medium)” (0803) which is a holding unit, the “built-in clock” (0804) which is a time information output unit, the “interface” (0805) which is a recording command acquisition unit, and a content acquisition unit There is also a “Reception Tuner” (0806). Then, they are connected to each other through a data communication path such as “system bus” (0808) to transmit / receive information and process information.

  The “storage device” stores various programs executed by the “CPU”, a device ID that is device unique identification information, and the like. In addition, the “main memory” provides a work area which is a work area for the program as well as being read for executing the program stored in the “storage device”. A plurality of memory addresses are assigned to each of the “main memory” and “storage device”, and programs executed by the “CPU” exchange data with each other by specifying and accessing the memory addresses. It is possible to perform processing.

  In addition, if the reception tuner is an analog broadcast wave reception tuner, it is equipped with an analog / digital converter for converting the broadcast wave into digital information, and the received content data is dedicated to the storage device and reception tuner. A function of storing in a temporary storage memory or the like is provided. The “interface” has a function of accepting a recording command by an operation panel of a device or a remote controller, and accepting a recording command by a graphical interface. The “built-in clock” has a function of measuring and outputting the current time.

  FIG. 9 shows an example of a list in which data used by a program for encrypting content is described in an XML format. As shown in this figure, for example, the video data “Japan Series 1989 Memorial” as the content is encrypted with the device ID “1111-xxx” and the time information “04050930”. Specifically, in the “interface”, a command for recording a program (content) being received by the “reception tuner” on the DVD medium, that is, a “new recording command” is acquired by, for example, a user's remote control operation. Then, the program received by the “reception tuner” is converted into digital data by a digital converter (not shown) and stored in the content and the HDD. Then, the contents are sequentially stored one by one in the memory address 1 of the “main memory” for the encryption process.

  Also, by acquiring a new recording command at the “interface”, the encryption program stored in the “storage device” is expanded in the work area of the main memory and temporarily stored in the main memory or the like as described above. The encrypted content is encrypted. For this purpose, the encryption program first sends out an instruction “obtain information on the memory address α of the storage device and store it in the memory address 2 of the main memory”. Then, in accordance with the command, the device ID (device unique identification information) stored in the memory address α is read from the storage device and stored in the memory address 2 of the main memory. Also, according to the command transmission of the encryption program “Acquire current time information timed by internal clock and store it in memory address 3 of main memory”, time information 1 (new recording command) timed by internal clock Is stored in the memory address 3 of the main memory. Similarly, the one-way function for generating the encryption key is read from a predetermined memory address of the “storage device” and stored in the memory address X of the “main memory”.

  Subsequently, the encryption program “Substitutes the information of the memory address 2 and the memory address 3 of the main memory into the one-way function of the memory address X to generate an encryption key and store it in the memory address Y”. In accordance with the instruction, the CPU performs a calculation process for generating an encryption key from the data using a function, and the generated encryption key is stored in the memory address Y of the main memory. Then, according to the instruction of the encryption program, “encrypt (part of the contents of the memory address 1 of the main memory with the encryption key of the memory address Y and store it in the memory address Z of the main memory”) Using the generated encryption key, content encryption processing is executed by arithmetic processing of the “CPU”. Then, the encrypted content is stored at the memory address Z of the main memory. Subsequently, since another part of the content is encrypted, it is similarly stored in the memory address 1 of the “main memory”, and the above processing is sequentially performed until the entire content is encrypted.

  Another writing program is expanded in the work area, and the encrypted content stored in the memory address Z of the main memory is temporarily stored in a dedicated buffer memory provided in the “writing device”, and recorded on the recording medium. For example, it is written on DVD media or the like. Also, the time information is written on the DVD medium in association with, for example, information on the file system, which is additional information related to the encrypted content, or information indicating a recording area that is determined to be accessible only at the time of decryption as described above. Condition.

    <Processing Flow in New Recording of First Embodiment> FIG. 10 is a flowchart showing an example of a new recording process on the recording medium. As shown in this figure, first, when a new recording command is acquired (step S1001), content is acquired (step S1002). In addition, time information at the new recording command acquisition timing is also output and acquired (step S1003), and device unique identification information is also acquired (step S1004).

  Subsequently, using the encryption key based on the acquired device unique identification information and time information, an encrypted content is generated from the content acquired in step S1002 (step S1005). The information is written on the recording medium in association with the time information at the recording command acquisition timing acquired in step S1003 (step S1006).

  As described above, since the content is encrypted by the encryption key generated based on the time information together with the device unique identification information and written in the recording medium, the time information included in the additional information of the encrypted content is different. Then, the encrypted content cannot be normally decrypted and reproduced. By utilizing this fact, in the next copy writing unit, when the content is illegally copied, the copyright of the content can be protected by rewriting the time information. It is desirable to perform processing such as embedding the time information in the content itself rather than the file system so that it cannot be easily modified by the user, or encrypting the time information itself.

  The “copy writing unit” (0206, 0306) is a copy recording unit when the recording command acquired by the recording command acquisition unit is a copy recording command of encrypted content written in the past by the new writing unit. It has a function of updating the time information associated with the copy target encrypted content with the time information at the instruction acquisition timing, and copying and writing the copy target encrypted content to the medium. “Copy writing” means recording the content data on another recording medium while leaving the content data at the copy source.

  FIG. 11 is a conceptual diagram for explaining an example of a process for recording content on a recording medium in the copy writing unit. As shown in this figure, first, in the recording command acquisition unit, for example, a “copy recording command” is acquired by a remote control operation or the like. Then, for example, from the recording medium set in the reading drive of the recording medium, the “encrypted content” recorded by the new writing unit is read together with the time information “April 5, 19:30” as additional information. . Then, the encrypted content is copied and written on another recording medium in accordance with a copy recording command.

  However, at this time, the copy writing unit uses the time information “April 5, 19:30” included as the additional information of the encrypted content as the time information when the copy recording command is acquired, for example, “ It is characterized in that the process is updated to "April 9, 10:00" and written to another recording medium. Accordingly, the encrypted content copied from the recording medium A to another recording medium B by the content recording / reproducing apparatus of the present embodiment does not have a correct key for decryption, and therefore cannot be normally reproduced. . Accordingly, unauthorized distribution due to content copying can be prevented.

  The update of the time information by copying is a process executed as a normal OS (operating system) process. Therefore, in this embodiment in which the time information is one of the encryption keys, a normal OS-based control system is simply incorporated into a digital content recording / playback device without creating a special time information program for that purpose. It also has the effect that it can be realized easily.

  FIG. 12 is a schematic diagram showing an example of a hardware configuration in the content recording / playback apparatus of the present embodiment. The operation of each hardware component in the process of copying and writing content to a recording medium will be described with reference to FIG. As shown in this figure, the content recording / playback apparatus includes a “CPU” (1201), a “main memory” (1202), and a “writing device” (1207) which are copy writing units. . In addition, a “storage device (or storage medium)” (1203) as a holding unit, an “internal clock” (1204) as a time information output unit, an “interface” (1205) as a recording command acquisition unit, and a content acquisition unit A certain “reading device (may be the same as the writing device)” (1206) is also provided. Then, they are connected to each other through a data communication path such as a “system bus” (1208) to transmit / receive information and process information.

  Similarly to the above-described new writing process, a plurality of memory addresses are assigned to the “main memory” and “storage device”, respectively, and a program executed by the “CPU” specifies and accesses the memory address. In this way, data can be exchanged and processed.

  The “reading device” has a function of reading data from the recording medium on which the encrypted content is recorded by the new writing process, and the “interface” is a copy using the operation panel of the device or the remote control or the graphical interface on the display. A function for receiving a recording command is provided. The “built-in clock” has a function of measuring and outputting the current time.

  FIG. 13 shows an example of a list in which data used by a program for copying content is described in an XML format. As shown in this figure, for example, the copy recording command is acquired for the time information “04051930” included in the additional information of the video data “Japan Series 1989 Memorial” which is the encrypted content (encrypted), for example. The update time information is “04091000” indicating the update timing. Specifically, the recording medium A on which the encrypted content is recorded is set in the “reading device”, and an instruction to copy the encrypted content of the recording medium to another recording medium B at the “interface”, that is, “ The “copy recording command” is acquired by, for example, a user's remote control operation. Then, according to the instruction of the copying program developed in the work area of the “main memory”, the “reading device” stores the data of the encrypted content recorded on the recording medium A and the time information 1 (record on the encrypted content). Time information when a new recording command to the medium A is acquired) is read and stored in the memory addresses 1 and 2 of the “main memory”.

  In addition, the time information 2 (duplicated by the built-in clock) is transmitted in accordance with the command transmission of the copy program “Acquire the current time information measured by the built-in clock and store it in the memory address 3 of the main memory”. Information indicating the time when the recording command is acquired) is stored in the memory address 3 of the main memory. Then, in the copying program, “time information 1 stored in memory address 2 is updated with time information 2 stored in memory address 3 and additional information of the encrypted content stored in memory address 1 is updated. As a result, the encrypted content with the updated time information is written to the recording medium B by the “writing device” in accordance with the instruction “The writing device can perform the writing process on the recording medium (B)”. .

  In this copy recording, for example, the copy can be freely made up to 3 days after the new writing process. For example, if the copy command is within a predetermined time range, normal encrypted content can be decrypted. Alternatively, a configuration may be used in which data is written on a recording medium. FIG. 27 is a flowchart showing an example of the flow of processing in this configuration. As shown in this figure, first, when a copy recording command is acquired (step S2701), the copy target encrypted content recorded on the recording medium A and the time information T1 associated with the content are obtained. To be acquired. At the same time, the copy permission days information A indicating the copy permission days recorded on the recording medium A is also acquired (step S2702). Further, time information at the copy recording command acquisition timing is also output and acquired (step S2703).

  Subsequently, the time information T2 acquired in step S2703 is within the time obtained by adding the time information T1 acquired in step S2702 (the time when the new recording command for the encrypted content is acquired) and the copy permission days information A. It is determined whether it is included (step S2704). That is, it is determined whether or not a copy recording command has been acquired within the number of days permitted for copying. As a result, if the copy recording command acquisition exceeds the copy permission days (T2> T1 + A), the time information associated with the encrypted content to be copied is the time information T2 at the recording command acquisition timing acquired in step S2703. (Step S2705a), the updated time information and the encrypted content to be copied are associated with each other and written on another recording medium (step S2706a). In this case, since the permitted number of copying days has passed, information indicating that may be newly written on the recording medium.

  If the copy recording command is acquired within the copy permission days (T2 <T1 + A), the time information is not updated, and the encrypted content to be copied, the time information T1 associated with the content, and the copy permission The day information A is copied and written to the recording medium B (step S2705b).

  By performing such configuration and processing, the content holder or the like can freely restrict / permit the user's recording action. In addition, the time information may be updated depending on the number of times of copying and recording as described above. For example, by including the information indicating the number of times of copying and recording and the information indicating the number of times permitted for copying in the additional information of the encrypted content, for example, up to three times, the time information is not updated even in the case of a copy recording command. For example, when the information indicating the number of times of recording indicates four or more times, the time information is updated. FIG. 28 is a flowchart showing an example of the flow of processing in this configuration. As shown in this figure, first, when a copy recording command is acquired (step S2801), the encrypted content to be copied recorded on the recording medium A and the time information T1 associated with the content are obtained. To be acquired. At the same time, the number of copies c of the encrypted content recorded up to the present time and the number of permitted copies C of the content are also acquired (step S2802).

  Subsequently, the copy number c acquired in step S2802 is updated to c + 1 (step S2803), and it is determined whether the number c + 1 is equal to or less than the copy permission number C. That is, it is determined whether or not the copy command acquired so far exceeds the copy permission count. As a result, if the copy command has been acquired exceeding the permitted number of copies (C <c + 1), the time information at the copy recording command acquisition timing is output and acquired (step S2703) and associated with the encrypted content to be copied. The obtained time information T1 is updated to time information T2 at the recording command acquisition timing acquired in step S2703 (step S2705a). Then, the updated time information T2 and the encrypted content to be copied are associated with each other and written on another recording medium (step S2706a). In this case, the number of copies may be updated to c + 1 and written to the copy destination and copy source recording media, or information indicating this is newly added to both recording media when the number of permitted copies has been exceeded. You may write.

  If the number of times the copy command is acquired is within the permitted number of copies (C> c + 1), the time information is not updated, and the encrypted content to be copied as it is, the time information T1 associated with the content, and the update copy The number of times c + 1 and the number of permitted copies C are copied and written to another recording medium (step S2705b). Also, the copy count of the copy source recording medium is updated to c + 1 and recorded.

    <Processing Flow in Copy Recording of Example 1> FIG. 14 is a flowchart showing an example of copy recording processing to this recording medium. As shown in this figure, first, when a copy recording command is acquired (step S1401), the copy target encrypted content recorded on the recording medium A and the time information associated with the content are acquired. (Step S1402). Further, time information at the copy recording command acquisition timing is also output and acquired (step S1403).

  Subsequently, the time information associated with the acquired copy target encrypted content is updated to the time information at the recording command acquisition timing acquired in step S1403 (step S1404), and the updated time information and the copy target are updated. The encrypted content is associated and written on another recording medium by copying (step S1405).

    <Simple Explanation of Effect of First Embodiment> As described above, the content recording / playback apparatus of the present embodiment protects the copyright of the content by time information and does not rely on the identification information of the recording medium, and illegal copying. Can be prevented. Therefore, it is possible for the user to save the trouble of purchasing a recording medium to which identification information is specifically assigned for these techniques. In addition, there is no need to perform management of identification information allocation of recording media, and therefore there is an effect that no management cost is generated and there is no occurrence of a situation such as exhaustion of identification information.

  In addition, since the update of time information by copying is a process executed as a normal OS (operating system) process, a special time information program for this purpose is created in this embodiment using the time information as an encryption key. There is also an effect that a control system based on a normal OS can be easily realized by simply incorporating it into a recording / playback apparatus for digital content.

  Second Embodiment <Overview of Second Embodiment> FIG. 15 is a conceptual diagram for explaining an example of content movement recording processing by the content recording / playback apparatus of the present embodiment. As shown in FIG. 15, on the recording medium A, the content encrypted by the new recording process described in the first embodiment is recorded together with the time information. Here, the user considers recording the encrypted content recorded on the recording medium A on another recording medium B by using the content recording / reproducing apparatus of the present embodiment. As a recording form of the content on the recording medium B, the user selects recording by “move” instead of copying as described in the first embodiment. Then, as shown in the figure, the content of the recording medium A where the content was originally recorded is deleted, and the recording medium A becomes an empty medium. Then, the encrypted content is recorded on the recording medium B to which the content is moved without updating the time information. Therefore, since the recording medium B can normally decrypt the encrypted content based on the time information, the video of the content recorded on the recording medium B can be normally viewed. Of course, the decryption and reproduction are premised on reproduction by a content recording / reproducing apparatus in which the encrypted content is recorded on the recording medium A because the encrypted content is also encrypted by the device unique identification information.

  In this way, unlike the copy (copy) in which a large number of copies are created and the content is illegally distributed by the content recording / playback apparatus of the present embodiment, a large number of illegal copies are not generated by deleting the original. The user's free recording can be permitted for the content movement recording process.

    <Configuration of Second Embodiment> FIG. 16 is a diagram illustrating an example of functional blocks in the content recording / playback apparatus of the present embodiment. As shown in this figure, the “content recording / playback apparatus” (1600) of the present embodiment is based on the first embodiment and includes a “recording command acquisition unit” (1601), a “content acquisition unit” (1602), It has a “holding unit” (1603), a “time information output unit” (1604), a “new writing unit” (1605), and a “copy writing unit” (1606). The feature of this embodiment is that the command acquired by the “recording command acquiring unit” is a moving recording command, and the content recording / playback apparatus further includes a “moving writing unit” (1607). It is. The “recording command acquisition unit”, “content acquisition unit”, “holding unit”, “time information output unit”, “new writing unit”, and “copy writing unit” Since it has already been described in 1, its description is omitted.

  The “mobile writing unit” (1607) is a case where the recording command acquired by the recording command acquiring unit (1601) is a moving recording command of encrypted content written in the past by the new writing unit (1605). In addition, there is a function of moving and writing the moving target encrypted content and the time information associated therewith as they are without updating the time information associated with the moving target encrypted content. As described above, the “moving recording command” is a command for moving and recording to another recording medium after deleting the content on the recording medium of the copy source, for example.

  FIG. 17 is a diagram for explaining an example of the “movement recording command” acquired by the recording command acquisition unit. As shown in this figure, the moving recording command is a command for deleting, for example, the content α recorded on the recording medium A and then moving (moving) the content α to another recording medium B for recording. is there. For example, the acquisition may be performed by selecting and clicking the move start button β of the graphical interface displayed on the display with a keyboard or a mouse.

  FIG. 18 is a conceptual diagram for explaining an example of a process for recording content on a recording medium in the copy writing unit. As shown in this figure, first, in the recording command acquisition unit, for example, a “moving recording command” is acquired by a remote control operation or the like. Then, for example, from the recording medium on which the encrypted content is recorded by the new writing unit set in the reading drive of the recording medium, the time information “April 5, 19:30 at the“ encrypted content ”is additional information. Read out along with "minutes". Then, the encrypted content is copied and written on another recording medium in accordance with the moving recording command. In addition, since it is transfer recording, the original encrypted content is erased from the transfer source recording medium.

  In this mobile writing unit, unlike the copy writing unit, the time information “April 5, 19:30” included as the additional information of the encrypted content is not updated, and another recording is performed as it is. It is characterized by performing processing for writing together with encrypted content on a medium. Therefore, since the encrypted content moved from the recording medium to another recording medium by the content recording / reproducing apparatus of the present embodiment has a correct key for decryption, normal reproduction can be performed. In addition, the movement process performed without updating the time information included in the additional information of the content is a process executed as a normal OS (operating system) process. Therefore, in this embodiment, it is possible to easily realize a control system based on a normal OS simply by incorporating it into a recording / playback apparatus for digital contents without creating a special time information program. Also play.

  FIG. 19 is a schematic diagram illustrating an example of a hardware configuration in the content recording / playback apparatus according to the present embodiment. The operation of each hardware component in the content moving / writing process to the recording medium will be described with reference to FIG. As shown in this figure, the content recording / playback apparatus includes a “CPU” (1901) which is a mobile writing unit, a “main memory” (1902), and a “writing device” (1907). . In addition, a “storage device (or storage medium)” (1903) that is a holding unit, an “internal clock” (1904) that is a time information output unit, an “interface” (1905) that is a recording command acquisition unit, and a content acquisition unit A certain “reading and rewriting device (may be the same as the writing device)” (1906) is also provided. These are connected to each other through a data communication path such as a “system bus” (1908) to transmit / receive information and process information.

  Similarly to the new writing process and the copy writing process, a plurality of memory addresses are assigned to the “main memory” and the “storage device”, and the program executed by the “CPU” By specifying and accessing, data can be exchanged and processed.

  In addition, the “reading device” has a function of reading data from the recording medium on which the encrypted content is recorded by the new writing process, and the “interface” is moved by the operation panel of the device or the remote control or the graphical interface on the display. A function for receiving a recording command is provided. The “built-in clock” has a function of measuring and outputting the current time.

  FIG. 20 shows an example of a list in which data used by a program for moving and writing content is described in the XML format. As shown in this figure, for example, the video data “Japan Series 1989 Memorial” which is the encrypted content (encrypted) and the time information “04050930” included in the additional information of the video data, for example, remain as they are. Moving writing is performed on the recording medium by the writing device. Specifically, the recording medium A on which the encrypted content is recorded is set in the “reading / rewriting device”, and an instruction to move the encrypted content of the recording medium to another recording medium B at the “interface”, that is, The “movement recording command” is acquired by, for example, a user's remote control operation. Then, according to the instruction of the mobile rewriting program developed in the work area of the “main memory”, the “reading / rewriting device” stores the encrypted content data recorded on the recording medium A and the time information 1 (the encryption Time information when a new recording command to the recording medium A with respect to the digitized content is acquired) is read and stored in the memory addresses 1 and 2 of the “main memory”.

  At that time, in accordance with the instruction “Move the encrypted content recorded on the recording medium A by the reading / writing device” of the moving rewriting program, the data recorded on the recording medium by the “reading / writing device” An erasure process is performed. Then, the encrypted content stored at the memory address 1 of the mobile rewriting program is associated with the time information 1 stored at the memory address 2, and the writing device writes data to the recording medium (B). The encrypted content and the time information 1 are written to the recording medium B by the “writing device” in accordance with the command “do it”.

  In this moving recording, the time information may be updated depending on the number of times of moving recording. For example, if the additional information of the encrypted content includes information indicating the number of times of moving recording and information indicating the number of times of movement recording, for example, if the information indicating the number of times of moving recording indicates four times or more, the copy For example, the same processing as recording is performed.

  The order of the recording process of the encrypted content on another recording medium and the erasing process of the encrypted content on the transfer source recording medium is the same as the above, and the recording process on another recording medium is executed first. Then, the configuration may be such that the encrypted content of the recording medium at the movement source is erased. However, in that case, after the migration writing process to another medium is finished, before the migration target encrypted content is erased, for example, the DVD medium that is the migration source recording medium is taken out from the DVD drive and illegal duplication is performed. It is desirable to provide a function of locking the tray for storing the recording medium of the “reading device” of the recording medium so that it cannot be operated during the above processing.

    <Flow of Processing in Moving Recording of Second Embodiment> FIG. 21 is a flowchart showing an example of moving recording processing on this recording medium. As shown in this figure, first, when a moving recording command is acquired (step S2101), the moving target encrypted content recorded in the recording medium A and the time information associated with the content are acquired. (Step S2102).

  Subsequently, the acquired encrypted content to be moved and time information are associated with each other and written to another recording medium B (step S2103). Further, the content recorded on the recording medium A as the movement source is erased (step S2104).

    <Simple Explanation of Effects of Second Embodiment> As described above, unlike the copy (copy) in which a large number of copies are created and content is illegally distributed by the content recording / playback apparatus of the present embodiment, the original is copied. By deleting, it is possible to allow the user to record freely regarding the moving recording process of the content in which a large number of unauthorized copies are not generated.

  In addition, since the moving recording of data without updating the time information is a process executed as a normal OS (operating system) process, in this embodiment using the time information as an encryption key, special time information for that purpose is used. There is also an effect that a control system based on a normal OS can be realized simply by incorporating it into a digital content recording / playback device without creating a program.

  Embodiment 3 <Overview of Embodiment 3> FIG. 22 is a conceptual diagram for explaining an example of content playback by the content recording / playback apparatus of the present embodiment. As shown in this figure, the encrypted content is written on the recording medium by the new recording process described in the first embodiment by the content recording / playback apparatus 1 holding the device ID: α. That is, the content encrypted using the encryption key based on the device ID: α and the time information of the acquisition timing of the new recording command is recorded on this recording medium. Therefore, this recording medium can be normally played back by the content recording / playback apparatus 1 having the device ID: α used for recording the content, but is encrypted by the content recording / playback apparatus 2 having the device ID β. Since there is no key device ID: α, it cannot be decrypted normally and cannot be reproduced.

  As described above, the content recording / playback apparatus according to the present embodiment can prevent a situation in which a large number of copies are distributed due to unauthorized copying of content and played back on an unspecified platform. Therefore, the copyright protection effect of the content can be further enhanced.

    <Configuration of Third Embodiment> FIG. 23 is a diagram illustrating an example of functional blocks in the content recording / playback apparatus of the present embodiment. As shown in this figure, the “content recording / playback apparatus” (2300) of the present embodiment is based on the first embodiment and includes a “recording command acquisition unit” (2301), a “content acquisition unit” (2302), It has a “holding unit” (2303), a “time information output unit” (2304), a “new writing unit” (2305), and a “copy writing unit” (2306). Further, although not shown in the figure, a “mobile writing unit” may be provided on the basis of the second embodiment. It should be noted that “recording command acquisition unit”, “content acquisition unit”, “holding unit”, “time information output unit”, “new writing unit”, “copy writing unit”, and “moving document” Since the “embedding portion” has already been described in the first and second embodiments, the description thereof will be omitted. The feature of this embodiment is that it further includes a “time information acquisition unit” (2307) and a “decoding unit” (2308).

  The “time information acquisition unit” (2307) has a function of acquiring time information associated with the encrypted content acquired by the content acquisition unit (2302). Then, based on the acquired time information and device unique identification information, the encrypted content is decrypted by the next decryption unit. In addition, the acquisition of the time information in this time information acquisition unit includes an example of an acquisition method by the following processing. For example, the time information is stored in a predetermined area of the recording medium, and the time information storage area of the recording medium is random and the time information storage area of the recording medium is random. For example, the time information is acquired by designating the time information storage area by taking a configuration in which the information indicating is stored in a predetermined storage medium area.

  The “decryption unit” (2308) uses the device unique identification information held by the holding unit (2303) and the time information acquired by the time information acquisition unit (2307) as keys, and the content acquisition unit (2302). It has a function of decrypting the encrypted content acquired in (1).

  FIG. 24 is a conceptual diagram for explaining an example of the decrypting process of the encrypted content in the decrypting unit. As shown in this figure, first, the “encrypted content” recorded on the set recording medium and the time information “April 5, 19:30 on the reading drive of the DVD medium which is the content acquisition unit, for example. Min. "Is acquired. This encrypted content includes the time information “April 5, 19:30” and device-specific identification information “1111-xxx” held in a non-volatile memory as a holding unit, for example. As a decryption key, the decryption unit performs decryption processing and decrypts the decryption key. For example, a video of the Japanese series of the content is displayed on a display or the like.

  FIG. 25 is a schematic diagram illustrating an example of a hardware configuration in the content recording / playback apparatus according to the present embodiment. The operation of each hardware component in the decryption processing of the encrypted content recorded on the recording medium will be described using this figure. As shown in this figure, the content recording / playback apparatus includes a “CPU” (2501) as a decryption unit and a “main memory” (1902). Also, a “storage device (or storage medium)” (2503) as a holding unit and a “reading device” (2504) as a content acquisition unit and a time information acquisition unit are provided. Also, a “video memory” (2505) and a “display” (2506) for outputting and displaying the decrypted and reproduced content are provided, and these are mutually connected by a data communication path such as a “system bus” (2507). Connected, sends and receives information and processes.

  Similarly to the above-described new write processing, a plurality of memory addresses are assigned to the “main memory” and “storage device”, respectively, and a program executed by the “CPU” specifies and accesses the memory address. By doing so, it is possible to exchange data and perform processing. Further, the “reading device” has a function of reading the encrypted content and time information data from the recording medium on which the encrypted content is recorded by the new writing process.

  First, the recording medium A on which the encrypted content is recorded is set in the “reading / rewriting device”, and the playback instruction of the encrypted content on the recording medium is obtained by remote control operation or the like through an interface (not shown). Then, according to the instruction of the decryption program developed in the work area of the “main memory”, the data of the encrypted content recorded in the recording medium A by the “reading device” and the time information 1 (the encrypted data) Time information when a new recording command to the recording medium A for the content is acquired) is read and stored in the memory addresses 1 and 2 of the “main memory”.

  Also, the device ID stored in the “storage device” is in accordance with the instruction “decode the device ID stored in the memory address A of the storage device and store it in the memory address 3 of the main memory” of the decryption program. Is read and stored in memory address 3 of “main memory”. The decryption program “decrypts the encrypted content stored at memory address 1 using the time information 1 stored at memory address 2 and the device ID stored at memory address 3 as keys. The content is decrypted by the computation processing of the “CPU” using the time information and the device ID as keys in accordance with the instruction “Perform processing and store decrypted content in memory address W”. The decrypted content is stored at the memory address W of the main memory.

  Then, another playback program, which is another program, is expanded in the work area of the main memory, and the decoded data stored in the memory address W of the main memory is decoded by the CPU according to the instruction of the playback program, It is stored in “memory” (2505). And according to the decoded content, the content is normally displayed on the display.

    <Process Flow in Decryption of Embodiment 3> FIG. 26 is a flowchart showing an example of the decryption process of the encrypted content. As shown in this figure, first, encrypted content is acquired (step S2601), and time information associated with the encrypted content is also acquired (step S2602). Also, device unique identification information is acquired (step S2603).

  Then, the encrypted content is decrypted using a key based on the acquired device unique identification information and time information (step S2604).

    <Simple Explanation of Effects of Third Embodiment> As described above, a situation in which a large number of duplicates are disseminated by unauthorized copying of content and reproduced on an unspecified platform by the content recording / playback apparatus of the present embodiment. Can be prevented. Therefore, the copyright protection effect of the content can be further enhanced.

Conceptual diagram for describing an example of writing, copying, and reproduction of content on a recording medium by the content recording / reproducing apparatus of Example 1 The figure showing an example of the functional block in the content recording / reproducing apparatus of Example 1. FIG. The figure showing an example of the functional block in the content recording / reproducing apparatus of Example 1. FIG. The figure for demonstrating an example of the "new recording command" acquired in the recording command acquisition part of the content recording / reproducing apparatus of Example 1 The figure for demonstrating an example of the "copy recording command" acquired by the recording command acquisition part of the content recording / reproducing apparatus of Example 1. FIG. FIG. 3 is a conceptual diagram for explaining an example of a process for recording content on a recording medium in a new writing unit of the content recording / playback apparatus according to the first embodiment. Conceptual diagram for describing an example of an encryption process in a new writing / recording process in a new writing unit of the content recording / playback apparatus according to the first embodiment. Schematic showing an example of the hardware configuration in the content recording / reproducing apparatus of Example 1. FIG. The figure showing an example of the list which described the data which the program which encrypts a content uses in the XML format in the new writing part of the content recording / reproducing apparatus of Example 1 7 is a flowchart illustrating an example of a new recording process on a recording medium in the content recording / playback apparatus according to the first embodiment. FIG. 3 is a conceptual diagram for explaining an example of a process for recording content on a recording medium in a copy writing unit of the content recording / playback apparatus according to the first embodiment. Schematic showing another example of the hardware configuration of the content recording / reproducing apparatus of the first embodiment. The figure showing an example of the list which described the data which the program which encrypts a content uses in the XML format in the copy writing part of the content recording / reproducing apparatus of Example 1 6 is a flowchart illustrating an example of copy recording processing to a recording medium in the content recording / playback apparatus according to the first embodiment. Conceptual diagram for explaining an example of content movement recording processing by the content recording / playback apparatus according to the second embodiment. The figure showing an example of the functional block in the content recording / reproducing apparatus of Example 2. FIG. The figure for demonstrating an example of the "movement recording command" acquired by the recording command acquisition part of the content recording / reproducing apparatus of Example 2. FIG. FIG. 7 is a conceptual diagram for explaining an example of a process for recording content on a recording medium in a copy writing unit of the content recording / reproducing apparatus in the second embodiment. Schematic showing an example of the hardware configuration in the content recording / reproducing apparatus of Example 2. FIG. An example of a list in which data used by a program for moving and writing content is described in XML format in the mobile writing unit of the content recording / playback apparatus according to the second embodiment. 10 is a flowchart illustrating an example of a moving recording process to a recording medium in the content recording / playback apparatus according to the second embodiment. Conceptual diagram for describing an example of content reproduction by the content recording / reproducing apparatus of the third embodiment The figure showing an example of the functional block in the content recording / reproducing apparatus of Example 3. FIG. 7 is a conceptual diagram for explaining an example of decryption processing of encrypted content in the decryption unit of the content recording / playback apparatus according to the third embodiment. Schematic showing an example of the hardware configuration in the content recording / reproducing apparatus of Example 3. FIG. 7 is a flowchart illustrating an example of a process for decrypting encrypted content in the content recording / playback apparatus according to the third embodiment. 7 is a flowchart showing another example of a copy recording process on a recording medium in the content recording / playback apparatus according to the first embodiment. 6 is a flowchart showing still another example of copy recording processing to a recording medium in the content recording / playback apparatus according to the first embodiment. Conceptual diagram for simply explaining an example of a medium on which content is recorded using the conventional CPPM technology, and copyright protection of the content thereby

Explanation of symbols

0200 Content recording / playback apparatus 0201 Recording command acquisition unit 0202 Content acquisition unit 0203 Holding unit 0204 Time information output unit 0205 New writing unit 0206 Copy writing unit

Claims (6)

A recording command acquisition unit for acquiring a plurality of types of recording commands;
A content acquisition unit for acquiring content;
A holding unit for holding device unique identification information;
A time information output unit for outputting time information;
When the recording command acquired by the recording command acquisition unit is a new recording command,
Generate encrypted content from the acquired content using the encryption key based on the device unique identification information and the time information at the recording command acquisition timing, and the generated encrypted content and the time at the recording command acquisition timing A new writing unit for associating information and writing to the medium;
When the recording command acquired by the recording command acquisition unit is a copy recording command of the encrypted content written in the past by the new writing unit,
A copy writing unit for updating the time information associated with the copy target encrypted content and copying the copy target encrypted content on the medium with the time information at the copy recording command acquisition timing;
A content recording / playback apparatus comprising: When the recording command acquired by the recording command acquisition unit is a moving recording command of the encrypted content written in the past by the new writing unit,
A mobile writing unit for moving and writing the moving target encrypted content and the time information associated therewith as they are without updating the time information associated with the moving target encrypted content;
The content recording / reproducing apparatus according to claim 1, further comprising: A time information acquisition unit for acquiring time information associated with the encrypted content acquired by the content acquisition unit;
The encrypted content acquired by the content acquisition unit is decrypted using a key based on the device unique identification information held by the holding unit and the time information acquired by the time information acquisition unit. A decryption unit;
The content recording / reproducing apparatus according to claim 1, further comprising: A recording step for recording in the device to retain the device unique identification information;
A recording command acquisition step for acquiring a plurality of types of recording commands;
A content acquisition step of acquiring content;
When the recording command acquired in the recording command acquisition step is a new recording command, a device specific identification information acquisition step of acquiring device specific identification information recorded and held in the recording step;
A first time information acquisition step of acquiring time information at the new recording command acquisition timing;
An encrypted content generation step of generating encrypted content from the acquired content using an encryption key based on the acquired device unique identification information and time information;
A new writing step of writing the encrypted content and the time information at the recording command acquisition timing in association with the medium;
Second information for acquiring time information at the copy recording command acquisition timing when the recording command acquired in the recording command acquisition step is a copy recording command of the encrypted content written in the past in the new writing step; A time information acquisition step;
A copy writing step of updating the time information associated with the copy target encrypted content with the time information at the acquired copy recording command acquisition timing, and copying and writing the copy target encrypted content to the medium;
A content recording / playback method comprising:   If the recording command acquired in the recording command acquisition step is a moving recording command of encrypted content written in the past in the new writing step, update the time information associated with the encrypted content to be transferred. 5. The content recording / reproducing method according to claim 4, further comprising a moving writing step of moving and writing the encrypted content to be moved and the time information associated therewith as it is to the medium. An encrypted content acquisition step of acquiring encrypted content written in the past in the new writing step;
A decryption time information acquisition step for acquiring time information associated with the encrypted content acquired in the encrypted content acquisition step;
Acquired in the content acquisition step using the decryption device specific information acquisition step for acquiring the device specific identification information recorded and held in the recording step, and the acquired time information and listening specific identification information as keys. A decryption step for decrypting the encrypted content;
The content recording / reproducing method according to claim 1, further comprising:

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