JP2008309959A - Audio signal recording device and electronic file - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To introduce a privacy protection mechanism with respect to a recording system of an audio signal. <P>SOLUTION: The audio signal recording device detects a speech section including a signal component of human speech from a whole section of an input original audio signal, and performs encryption processing for the signal in the speech section, and thereby, an encrypted audio signal is generated from the original audio signal. Then, the encrypted audio signal, decode information for decoding the encrypted audio signal, and right management information for controlling and switching permission/forbidding for decoding of the encrypted audio signal according to the information for decoding, and playback output of the original audio signal, are stored in the electronic file correspondingly to each other. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an audio signal recording apparatus for recording audio signals, an audio signal recording / reproducing apparatus for recording and reproducing audio signals, and an imaging apparatus such as a digital video camera. The present invention also relates to an electronic file storing an audio signal. The present invention also relates to an information providing device, a terminal device, an audio signal reproducing device, and an electronic file recording method related to each of the above devices or electronic files.

  In recent years, audio signal data recorded by a digital video camera or voice recorder is often published on a website such as a social networking service (hereinafter abbreviated as “SNS”) or a so-called blog via the Internet. ing. Until now, recorded data that has been viewed (viewed) only among family members and acquaintances can be viewed by an unspecified number of people by publishing it via the Internet. Against this background, the need for technology that protects the privacy of public data has been pointed out. What is important for protecting the privacy of the audio signal is a portion including the voice of the speaker, and if the data in the portion is appropriately handled, the privacy of the speaker is protected.

  Note that there are techniques described in Patent Documents 1 and 2 below as conventional techniques related to audio signals.

  The technique of Patent Document 1 is a technique for protecting music information that is subject to copyright protection, and is not a technique that can be provided for a scene where a person is talking.

  In the technique of Patent Literature 2, the provided data is divided into a plurality of blocks, and a security level is set for each block. Then, at the time of reproduction, it is determined whether or not the provision of data of each block is permitted according to the set security level. In this technique, it is necessary to work to divide the blocks and set the security level for each block when data is provided.

JP 2001-76431 A JP 2004-287525 A

  Therefore, the present invention provides an audio signal recording device, an audio signal recording / reproducing device, an imaging device, an electronic file, an information providing device, a terminal device, an audio signal reproducing device, and an electronic file recording method that contribute to privacy protection related to audio signals. The purpose is to do.

  In order to achieve the above object, an audio signal recording apparatus according to the present invention includes a speech section detecting means for detecting a speech section including a signal component of human speech from all sections of an input original audio signal, An encryption means for generating an encrypted audio signal from the original audio signal by performing an encryption process on the signal in the voice section of the original audio signal, the encrypted audio signal, and the encryption And a recording control unit that records in the recording unit an electronic file in which the decoding information for decoding the audio signal is stored in association with each other.

  When the electronic file is stored on the audio signal recording device, the encryption process is performed, and the audio signal in the audio section in the electronic file is encrypted. Therefore, even if the electronic file leaks illegally, Privacy is protected. In addition, since a voice section important for privacy protection is automatically detected and encryption processing is automatically performed on the voice section, the burden on the user for protecting privacy is extremely small.

  And, for example, the recording control means controls authority to switch permission / prohibition for decrypting the encrypted audio signal according to the decryption information and reproducing and outputting the original audio signal obtained by the decryption. Information is further stored in the electronic file in association with the encrypted audio signal and the decryption information.

  By appropriately setting the authority management information, it is possible to control the reproduction of the original audio signal in accordance with the user's intention.

  Specifically, for example, the decoding information includes speech section information indicating which section of the entire section is the speech section.

  More specifically, for example, the encryption unit excludes a signal in a section other than the speech section in the original audio signal from the target of the encryption process.

  In addition, for example, the voice section is composed of a plurality of different element sections, and the audio signal recording apparatus determines whether the voice speaker and the registered speaker registered in advance are identical or inconsistent for each element section. Further comprising speaker recognition means, wherein the decoding information includes speech section information indicating which section of the entire section is the speech section and also indicating a discrimination result of the speaker recognition means for each element section. The recording control means includes permission / prohibition for decoding the encrypted audio signal of each element section according to the decryption information and reproducing and outputting the original audio signal of each element section obtained by the decryption. Authority management information for switching control is further stored in the electronic file in association with the encrypted audio signal and the decryption information, and the authority management information Includes a first rights management information for the element section including a signal component of a voice of the registered speaker, and the second authorization control information for the other elements section, the individual.

  An audio signal recording / reproducing apparatus according to the present invention includes the above-described audio signal recording apparatus. The authority management information includes an authentication code, and unique codes different from each other between the audio signal recording / reproducing device and the other audio signal recording / reproducing device are given in advance to the audio signal recording / reproducing device, The audio signal recording / reproducing apparatus includes reproduction / output means for reproducing / outputting an audio signal, decryption processing means for decoding the encrypted audio signal based on the decryption information, and the authentication code and the audio signal recording / reproducing apparatus. It is determined whether or not reproduction output of the original audio signal obtained by decoding of the decoding processing unit is permitted in the reproduction output unit based on a verification result of the verification unit and a verification result of the verification unit Discriminating means, and the decoding processing means and the reproduction output according to the discrimination result of the discriminating means And controlling the stage.

  Thereby, even when the recording medium on which the electronic file is recorded is lost, the privacy regarding the voice is protected.

  In addition, the imaging apparatus according to the present invention acquires an image corresponding to a subject. The audio signal recording apparatus or the audio signal recording / reproducing apparatus is provided.

  In addition, the electronic file according to the present invention is an encrypted audio signal obtained by performing encryption processing on a signal in a voice section including a signal component of human voice in the original audio signal. Data and decryption information data for decrypting the encrypted audio signal are stored in association with each other.

  And for example, authority management information data for switching permission / prohibition for decrypting the encrypted audio signal according to the decryption information and reproducing and outputting the original audio signal obtained by the decryption, and The data may be stored in an electronic file in association with the data of the encrypted audio signal and the data of the decryption information.

  Also, an information providing apparatus according to the present invention receives a digital file from the providing apparatus, receives the electronic file from the providing apparatus, and has a predetermined relationship with the providing apparatus and includes a reproduction output means for reproducing and outputting an audio signal. An information providing device that transmits information based on the electronic file to the terminal device via a communication network in accordance with a transmission request, wherein the encrypted audio signal in the electronic file is transmitted based on decryption information in the electronic file. Decoding processing means for decoding, and when there is a transmission request, based on the authority management information in the electronic file and the relationship, transmission of the original audio signal obtained by decoding of the decoding processing means to the terminal device It is characterized in that whether or not to permit is determined, and the transmission content to the terminal device is controlled according to the determination result.

  Thereby, it is possible to introduce a mechanism for protecting privacy related to audio signals in SNS and the like.

  Specifically, for example, the information providing apparatus recognizes the relationship in advance, and the first and second information is transmitted to the terminal device according to the authority management information and the relationship. An element obtained by decryption of the decryption processing means when there is the transmission request when giving any one of a plurality of authorities including an authority and giving the first authority to the terminal device An original audio signal obtained by decoding of the decoding processing means when the transmission request is made while the audio signal is transmitted to the terminal device and the second authority is given to the terminal device Is prohibited from being transmitted to the terminal device.

  Alternatively, for example, the information providing apparatus recognizes the relationship in advance, and the first, second, and third information is sent to the terminal device according to the authority management information and the relationship. An element obtained by decryption of the decryption processing means when there is the transmission request when giving any one of a plurality of authorities including an authority and giving the first authority to the terminal device When the audio signal is transmitted to the terminal device and the second authority is given to the terminal device, the first processed audio signal is generated from the original audio signal when the transmission request is made. When the first processed audio signal is transmitted to the terminal device and the third authority is given to the terminal device, a second processed audio signal is transmitted from the original audio signal when the transmission request is made. Generating a second signal and transmitting the second processed audio signal to the terminal device, wherein the first processed audio signal is generated by changing a voice characteristic in the voice section of the original audio signal; The second processed audio signal is generated by excluding an audio signal component from the audio section of the original audio signal.

  Further, the terminal device according to the present invention includes reproduction output means for reproducing and outputting an audio signal, receives information based on the electronic file from the information providing device via the communication network, and receives an audio signal based on the received information. Is reproduced and output by the reproduction output means.

  An audio signal reproducing apparatus according to the present invention includes file input means for receiving the electronic file and reproduction output means for reproducing and outputting the audio signal. The authority management information in the electronic file includes an authentication code, and the audio signal reproduction device decrypts the encrypted audio signal in the electronic file based on the decoding information in the electronic file. A verification unit for verifying the authentication code and a code registered in the audio signal reproduction device, and based on a verification result by the verification unit, the original audio signal obtained by decoding by the decoding processing unit Discriminating means for discriminating whether or not reproduction output by the reproduction output means is permitted, and controlling the decoding processing means and the reproduction output means in accordance with the discrimination result of the discrimination means.

  As a result, even when an electronic file is illegally leaked, privacy related to voice is protected.

  Also, the electronic file recording method according to the present invention is an encryption method obtained by performing encryption processing on a signal in a voice section including a signal component of a human voice in an original audio signal. Audio signal data and decryption information data for decrypting the encrypted audio signal are recorded in association with each other.

  ADVANTAGE OF THE INVENTION According to this invention, the audio signal recording device etc. which contribute to the privacy protection regarding an audio signal can be provided.

  The significance or effect of the present invention will become more apparent from the following description of embodiments. However, the following embodiment is merely one embodiment of the present invention, and the meaning of the term of the present invention or each constituent element is not limited to that described in the following embodiment. .

  Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings. In each of the drawings to be referred to, the same part is denoted by the same reference numeral, and redundant description regarding the same part is omitted in principle. The first to eighth embodiments will be described below, but the matters described in a certain embodiment can be applied to other embodiments as long as there is no contradiction.

<< First Example >>
First, a first embodiment of the present invention will be described. FIG. 1 is an internal block diagram of an audio signal recording apparatus 1 (hereinafter abbreviated as “recording apparatus 1”) according to the first embodiment. The recording apparatus 1 is provided with each part referred by the codes | symbols 11-15.

  The microphone unit 11 includes one or a plurality of microphones, collects ambient sounds of the recording apparatus 1 and converts the ambient sounds into digital electrical signals. This digital electrical signal is given to the audio signal processing unit 12 as an audio signal representing the peripheral sound of the recording apparatus 1. In the following description, an audio signal in a specific section is considered, and the entire specific section is regarded as all sections. The start time and end time of the specific section (that is, all sections) are designated by an operation on the operation unit 15.

  The audio signal processing unit 12 includes a voice detection unit (not shown in FIG. 1) that detects a section including a signal component of a human voice from all sections of the audio signal based on the audio signal from the microphone unit 11. The detected section including the signal component of the human voice is hereinafter referred to as “voice section”. Further, of all the sections of the audio signal, sections other than the voice section are referred to as “non-voice sections”. A person who utters the voice included in the audio signal is also called a speaker (or speaker).

  The audio signal processing unit 12 generates an encrypted audio signal by performing encryption processing according to a predetermined encryption method on the signal in the audio section among all the sections of the audio signal given from the microphone section 11. To do. At this time, the encryption process is not performed on the signal in the non-voice section. In order to clarify the distinction from the encrypted audio signal, the audio signal before being encrypted is hereinafter referred to as an original audio signal.

  A synthesized signal of a signal obtained by performing the above-described encryption processing on a signal in a voice section of the original audio signal and a signal (non-encrypted signal) in a non-voice section of the original audio signal is an encrypted audio signal. Become. However, predetermined processing (encoding processing or the like) other than encryption can be performed on the entire original audio signal.

  Any known encryption method can be used as the encryption method of the encryption process performed by the audio signal processing unit 12. For example, the bit string of the signal before encryption in the voice section is rearranged by a predetermined algorithm according to the encryption key, thereby generating the signal after encryption.

  The memory card 13 is an external recording medium, for example, an SD (Secure Digital) memory card. Although the memory card 13 is illustrated as an external recording medium, the external recording medium can be configured by one or a plurality of randomly accessible recording media (semiconductor memory, memory card, optical disk, magnetic disk, etc.). .

  The main control unit 14 creates a file storing the encrypted audio signal generated by the audio signal processing unit 12 and saves (records) the file in the memory card 13. Note that the recording apparatus 1 can store a file including an audio signal that is not encrypted at all in the memory card 13 in addition to the file that stores the encrypted audio signal. However, since the recording apparatus 1 has a feature in generating a file storing an encrypted audio signal, the file storing the encrypted audio signal is called a special file to distinguish it from other files. A description about the file shall be given.

  The operation unit 15 includes operation keys and the like, and accepts user operations. The operation content for the operation unit 15 is transmitted to the main control unit 14. By performing a predetermined operation on the operation unit 15, an original audio signal is acquired and a special file is created and stored.

  FIG. 2 shows the data structure of the special file 300 stored in the memory card 13. The special file 300 is formed from a header area 301 and a main body area 302. As a matter of course, the header area and the main body area defined in the same special file are associated with each other. In the case of the special file 300, the header area 301 and the main body area 302 are associated with each other, and the data stored in the special file 300 are associated with each other. The header area can also be called a user area.

  The main body area 302 stores data representing the encrypted audio signal. The header area 301 stores information related to the encrypted audio signal. Specifically, in the header area 301, voice section information, decryption key information, and authority management information are stored.

  The voice section information is information indicating which section of all sections of the original audio signal (or encrypted audio signal) is a voice section.

  The decryption key information is information representing a decryption key used for decryption processing for decrypting an encrypted signal. The above encryption processing is performed using an encryption key given in advance to the recording apparatus 1 or generated in the recording apparatus 1, and a decryption key corresponding to this encryption key is a decryption key. On a device that can restore the original audio signal from the encrypted audio signal (hereinafter referred to as “restoration device”), the encrypted audio signal can be decrypted using this decryption key (the decryption key is used for decryption). Must be required).

  By referring to the voice section information, the position of the encrypted voice section in all the sections can be known. Therefore, based on the voice section information and the decryption key information, the encrypted audio signal in the main body area 302 can be decrypted to restore the original audio signal. Therefore, the voice section information and the decryption key information form decryption information for decrypting the encrypted audio signal.

  Note that when the restoration device knows the decryption key without referring to the header area 301, it is not necessary to include the decryption key information in the special file 300 (common also in each embodiment described later). That is, for example, when the decryption key is given to the restoration device in advance, or when the user gives the decryption key to the restoration device by manual operation or the like, it is necessary to include the decryption key information in the special file 300. No.

  In the restoration device, it is possible to decrypt the encrypted audio signal according to the decryption information, and reproduce and output the original audio signal obtained by this decryption, but permission or prohibition to perform this decryption and reproduction output Information for switching control is authority management information. This usage example of the authority management information will be described in detail in another embodiment. When the user sets authority management information in the recording apparatus 1, an operation for the setting is performed on the operation unit 15.

  Even if the encrypted audio signal is reproduced without being decrypted, it is impossible to hear the human voice in the voice section. In order to return the encrypted audio signal to the original audio signal, it is essential to perform a decryption process according to the algorithm of the above-described encryption method. The restoration apparatus recognizes in advance information related to the algorithm of the encryption method in the audio signal processing unit 12, and can execute a decryption process according to the algorithm of the encryption method based on the information for decryption. . The original audio signal is restored from the encrypted audio signal by the decryption process. A user PC 2, a server 3, an audio signal recording / reproducing device 6, and an imaging device 7 described later function as a restoration device that can restore the original audio signal from the encrypted audio signal.

  What is important for privacy protection regarding the audio signal is a portion including the voice of the speaker, and if the audio signal including the voice of the speaker is distributed to an unspecified person, the privacy of the speaker may be impaired. However, since the encryption process is performed when the special file is stored on the recording device 1 and the audio signal in the special file is encrypted, the memory card 13 is lost or stolen, or a computer virus, Even if special files are leaked over the Internet due to misuse of file exchange software, privacy is protected. In addition, since a voice section involved in privacy protection is automatically detected and encryption processing is automatically performed on the voice section, the burden on the user for protecting the privacy is extremely small (as in Patent Document 2). It does n’t take a lot of time to divide the blocks.)

  Even when the decryption key information is included in the header area, the original audio signal can be correctly restored using the decryption key only on a legitimate device that knows the encryption algorithm. Since the execution / non-execution of the decryption process is managed according to the authority management information in the header area so as to conform to the user's intention (details will be described later), privacy is appropriately protected. Of course, the risk of unintentional decryption is reduced if the decryption key information is not included in the header area.

  The data storage format in the header area and the data storage format of the entire special file can be arbitrarily determined, but each data can be stored in accordance with existing standards. When creating and saving a special file in accordance with an existing standard, it is possible to reproduce and output the audio signal in the special file on an arbitrary playback device in accordance with the existing standard. Since the audio signal in the special file is encrypted, privacy is protected.

  The matters described in the first embodiment are applied to each embodiment described later and serve as a basis for the description of each embodiment described later.

<< Second Example >>
A second embodiment will be described as an embodiment showing an example of the internal configuration of the audio signal processing unit 12 of FIG. The second embodiment is implemented in combination with the first embodiment.

  FIG. 3 is an internal block diagram of the audio signal processing unit 12 of FIG. 1 according to the second embodiment. The audio signal processing unit 12 in FIG. 3 includes each part referred to by reference numerals 21 to 23.

  The AAC encoder 21 performs encoding processing on the original audio signal. This encoding process follows an AAC (Advanced Audio Coding) encoding method. AAC is an encoding method (compression method) for audio signals, which is standardized in MPEG (Moving Picture Experts Group).

  The original audio signal given to the audio signal processing unit 12 is a collection of digital signals (hereinafter referred to as discrete audio signals) arranged discretely on the time axis. In AAC, encoding and recording are performed using a discrete audio signal of 1024 samples as a unit interval, so in this embodiment, a speech interval and a non-speech interval are determined for each 1024 samples. The above unit section is called a frame. The entire original audio signal is formed from discrete audio signals of the first, second, third,..., (N−1) th and nth frames that come in sequence, and each frame is a discrete number of 1024 samples. An audio signal is included (n is an integer of 2 or more).

  The AAC encoder 21 encodes a discrete audio signal according to AAC for each frame. A signal obtained by this encoding is called an encoded signal, and an encoded signal obtained by encoding the discrete audio signal of the kth frame is called an encoded signal of the kth frame (k is 1 ≦ k ≦ n). The encoded signal of each frame is sent to the encryption processing unit 23.

  The voice / non-voice determination unit 22 determines, for each frame, whether the frame is a voice segment or a non-speech segment by a technique based on pitch extraction. Pitch is the fundamental frequency of an audio signal due to vocal cord vibration. Generally, when there is a lot of noise, it is difficult to find the pitch accurately, but in this embodiment, it is not necessary to search for the fundamental frequency accurately, and it is sufficient to determine only the presence or absence of the pitch. As a pitch extraction method, generally a method using autocorrelation processing is widely used, and autocorrelation processing is also used in this embodiment.

  The discriminating method of the voice / non-voice discriminating unit 22 will be described focusing on a certain frame. The focused frame is called a focused frame. Of the 1024 samples of discrete audio signals included in the frame of interest, the signal value of the t-th discrete audio signal is represented by x (t). t takes an integer value between 1 and 1024.

  Then, as shown in FIG. 4, the autocorrelation is calculated using the block composed of the 1st to 128th discrete audio signals as a reference block. That is, an evaluation block consisting of 128 continuous discrete audio signals is defined in the frame of interest, and the correlation between the reference block and the evaluation block is obtained while sequentially shifting the evaluation block. More specifically, the autocorrelation value S (p) is calculated according to the following formula (1). The autocorrelation value S (p) is a function of a variable p that determines the position of the evaluation block, and p is an integer that satisfies 0 ≦ p ≦ (1024−128).

  FIG. 5 shows the variable p dependency of the calculated autocorrelation value S (p). In FIG. 5, the horizontal axis is the variable p. FIG. 5 corresponds to the case where the pitch of interest is included in the frame of interest. When the pitch is included in the frame of interest, the autocorrelation value S (p) takes a large value periodically. When it is determined that the autocorrelation value S (p) periodically exceeds the predetermined threshold TH, the speech / non-speech discrimination unit 22 determines that the frame of interest is a speech interval, and otherwise, It is determined that the frame of interest is a non-voice segment. For example, when the interval of the variable p satisfying the inequality “S (p)> TH” is constant (or substantially constant), it is determined that the autocorrelation value S (p) periodically exceeds a predetermined threshold value TH. .

  The speech / non-speech discrimination unit 22 outputs information indicating whether each frame is a speech segment or a non-speech segment to the encryption processing unit 23. This information corresponds to the voice section information described in the first embodiment. In the second embodiment, the output information of the voice / non-voice discrimination unit 22 is stored in the header area 301 of FIG. 2 as the voice section information. It will be.

  The encryption processing unit 23 is based on the output information (speech interval information) of the voice / non-speech discriminating unit 22 and includes the first to nth frame encoded signals output from the AAC encoder 21 in the voice interval. Only the encoded signals of the classified frames are encrypted according to a predetermined encryption method. The encoded signal of the frame classified into the non-voice section is not encrypted. As described in the first embodiment, any known encryption method can be used as the encryption method of the encryption process performed by the audio signal processing unit 12 (encryption processing unit 23). .

  A combined signal of a signal obtained by performing encryption processing on an encoded signal of a frame classified as a speech section and an encoded signal itself of a frame classified as a non-speech section is an encryption processing unit as an encrypted audio signal. 23. This encrypted audio signal is stored in the main body area 302 of the special file 300 shown in FIG.

  In order to restore the original audio signal from the encrypted audio signal stored in the main body region 302, first, the encrypted encoded signal in the speech section is first decrypted based on the speech section information and the decryption key information. Thus, the encoded signals for the first to nth frames are obtained. Thereafter, the original audio signal can be restored by performing a decoding process for returning the AAC encoding to the encoded signal for each frame. This restoration method can be used in each restoration device that restores the original audio signal from the encrypted audio signal (the restoration device will be described later).

  Although the speech section and non-speech section discrimination method adapted to the AAC coding scheme has been illustrated, any other known method can be used as the speech section and non-speech section discrimination method.

<< Third Example >>
Next, a third embodiment will be described. In the third embodiment, it is assumed that a special file generated by the recording apparatus 1 is disclosed via a communication network.

  FIG. 6 shows an overall configuration diagram of a file management system that performs a characteristic operation in cooperation with the recording apparatus 1. In FIG. 6, reference numeral 2 denotes a user computer (hereinafter referred to as “user PC”). Reference numeral 3 denotes a server computer (hereinafter simply referred to as “server”). Reference numeral 4 denotes a communication network as a computer network. Now, it is assumed that the communication network 4 is the Internet. Reference numerals 101, 102, and 103 denote computers (hereinafter referred to as “browsing-side PCs”) that access files stored in the server 3, respectively.

  FIG. 7 shows a schematic internal block diagram of the user PC 2. User PC2 is provided with each part referred by numerals 41-48. FIG. 8 shows a schematic internal block diagram of the server 3. The server 3 is provided with each part referred with the codes | symbols 61-65. The browsing-side PCs 101 to 103 also have the same configuration as the user PC 2, and their internal block diagram is the same as that of FIG. The user PC 2 and the server 3 can transmit / receive arbitrary data via the communication network 4, and the server 3 and each of the viewing side PCs 101 to 103 can transmit / receive arbitrary data via the communication network 4. . For simplicity of illustration and convenience of explanation, only three browsing PCs are shown in FIG. 6, but many browsing PCs similar to the browsing PCs 101, 102, or 103 are connected via the communication network 4. It can be connected to the server 3.

  The recording device 1 in FIG. 1 creates a special file, and the special file is recorded on the memory card 13. The memory card 13 is detachable from the recording device 1. By removing the memory card 13 from the recording device 1 and inserting it into the card slot 44 of the user PC 2 in FIG. 7, the user PC 2 can read the special file recorded in the memory card 13. In addition, the special file in the memory card 13 mounted on the recording device 1 can be read by the user PC 2 via a communication line in accordance with a standard such as USB (Universal Serial Bus).

  The special file read by the user PC 2 is given to the main control unit 41 including the audio signal processing unit 42. A display unit 45 including a liquid crystal display or the like displays an image under the control of the main control unit 41. The audio signal reproduction output unit 46 includes a speaker, and reproduces and outputs an audio signal (outputs the audio signal as sound) under the control of the main control unit 41. Hereinafter, “audio signal reproduction output unit” is abbreviated as “reproduction output unit”. The PC operation key 47 receives a user operation of the user PC 2 and transmits the operation content to the main control unit 41. The stored contents of the memory 48 are referred to by the main control unit 41.

  When a predetermined operation is performed on the PC operation key 47 of FIG. 7, the special file given to the main control unit 41 is transmitted to the main control unit 61 including the audio signal processing unit 62 of the server 3 of FIG. (So-called uploading is performed). This transmission is performed via the communication unit 43 in FIG. 7, the communication network 4 in FIG. 6, and the communication unit 63 in FIG. The special file received by the main control unit 61 is stored in the server HDD (hard disk) 64 while being associated with the ID number assigned to the user PC 2.

  The server 3 is a WWW (World Wide Web) server to which a predetermined IP address is assigned on the Internet, and operates a website such as an SNS (social networking service) or a so-called blog.

  The server 3 receives a transmission request (distribution request) from each of the viewing-side PCs 101 to 103 via the communication network 4. When the server 3 receives a transmission request for the special file stored in the server HDD 64 from the viewing-side PC 101, the server 3 determines the data to be transmitted based on the content of the special file and the storage content of the public management memory 65, and the determination result Is sent to the viewing-side PC 101. The same applies to the viewing side PCs 102 and 103. The public management memory 65 can also be formed from a partial recording area in the server HDD 64.

  The file management system including the server 3 performs a characteristic operation with reference to information in the header area of the special file. This will be specifically described.

  For the sake of concrete explanation, it is assumed that the special file created in the recording apparatus 1 and uploaded (that is, transmitted) to the server 3 via the user PC 2 is the special file 300 in FIG. .

  It is assumed that different unique ID numbers are assigned in advance to the user PC 2 and the viewing-side PCs 101 to 103 in accordance with the rules of the SNS operated by the server 3 and the website. The public management memory 65 (see FIG. 8) of the server 3 stores in advance public management relation information indicating each ID number and the relation between the user PC 2 and each of the viewing side PCs 101 to 103. The relationship indicated by the public management relationship information is hereinafter referred to as “public relationship”.

  An example of the contents of the public management related information is shown in FIG. Now, it is assumed that the public relationships between the user PC 2 and the viewing side PCs 101, 102, and 103 are the first, second, and third public relationships, respectively, and information that represents them is public management relationship information. Suppose. Actually, the server 3 recognizes each public relation as shown in FIG. 9 using each ID number.

  By the way, in SNS or the like, generally, it is possible to apply disclosure restrictions to each piece of information to be disclosed. “Some information is disclosed to a browsing PC having an ID number corresponding to“ friend ”. However, the information on the public side (corresponding to the user PC 2) can be freely set such that the information is not disclosed to the browsing PC having the ID number corresponding to “friend of friend” or “general”. “General” means neither “friend” nor “friend of friend”. Therefore, the first to third public relations are defined in accordance with the SNS operated by the server 3 and the website public restrictions. Assume that the first, second, and third public relationships are assigned to “friends”, “friends of friends”, and “general” in the public restrictions, respectively.

  In this embodiment, it is assumed that the publication method is controlled based on the publication management relation information and the authority management information (see FIG. 2) in the header area 341, and the authority management information includes “publication level information”.

  The user can arbitrarily set the public level information on the recording device 1 through the operation of the operation unit 15 in FIG. 1 or on the user PC 2 through the operation of the PC operation key 47 in FIG. . When no operation for setting the public level information is performed on the recording device 1, the recording device 1 automatically stores specified initial data in the header area 341 as the public level information. The special file 300 is uploaded (that is, transmitted) to the server 3 via the user PC 2 and the communication network 4, and the server 3 associates the special file 300 with the ID number of the user PC 2 and the server HDD 64 (see FIG. 8). Save to.

  Consider a case where the disclosure method is classified into three stages according to the disclosure level information. An example of the content of the public level information in the header area 301 of the special file 300 stored in the server HDD 64 is shown in FIG. The contents for instructing the viewing-side PC having the first, second, and third public relations with the user PC 2 to give the first, second, and third authorities, respectively, are the public level information. Consider the case defined by In this case, the main control unit 61 of the server 3 in FIG. 8 gives the first, second, and third authorities to the viewing side PCs 101, 102, and 103, respectively, as the access authority for the special file 300 in the server HDD 64. It will be.

  The operation of the server 3 when each browsing PC tries to access the special file 300 in the server 3 under the above assumption will be described.

  FIGS. 11A, 11B, 11C, and 11D show audio signals transmitted to each browsing PC. 11A, 11B, and 11C, reference numeral 330 denotes an analog waveform of the original audio signal in the focused speech section. Reference numeral 331 in FIG. 11 (a), reference numeral 332 in FIG. 11 (b), and reference numeral 333 in FIG. 11 (c) respectively indicate the audio signals transmitted to the viewing PCs 101, 102, and 103 corresponding to the audio sections. It is an analog waveform. In FIG. 11D, reference numeral 340 denotes an analog waveform of the original audio signal in the focused non-speech section, and reference numeral 341 denotes the audio signal transmitted to each viewing PC (101, 102, and 103) in the non-speech section. It is an analog waveform, and both analog waveforms (340 and 341) are the same.

  When the browsing PC 101 issues a transmission request to the server 3 to transmit an audio signal corresponding to the special file 300 in the server 3 to the browsing PC 101, the main control unit 61 of the server 3 The authority to be given to the viewing PC 101 is recognized based on the public level information of the special file 300 and the public management relation information in the public management memory 65. As described above, the authority to be given to the browsing PC 101 is the first authority. In this case, the audio signal processing unit 62 (see FIG. 8) of the server 3 reads the encrypted audio signal and the decryption information in the special file 300 from the server HDD 64, and decrypts the encrypted audio signal based on the decryption information. To restore the original audio signal. Then, the data representing the restored original audio signal is transmitted to the browsing PC 101. As a result, the original audio signal including the analog waveform 331 in FIG. 11A and the analog waveform 341 in FIG. 11D is reproduced and output from the reproduction output unit including the speaker provided in the browsing PC 101.

  When the browsing PC 103 issues a transmission request to the server 3 to transmit an audio signal corresponding to the special file 300 in the server 3 to the browsing PC 103, the main control unit 61 of the server 3 The authority to be given to the viewing PC 103 is recognized based on the public level information of the special file 300 and the public management relation information in the public management memory 65. As described above, the authority to be given to the browsing PC 103 is the third authority. In this case, the audio signal processing unit 62 (see FIG. 8) of the server 3 reads the encrypted audio signal in the special file 300 from the server HDD 64, and based on the encrypted audio signal and the voice section information, utterance in the voice section. A second processed audio signal whose content cannot be specified is created.

  For example, a sine wave audio signal or a silent audio signal, which is completely different from the original audio signal, is inserted into the voice section of the second processed audio signal. Alternatively, when the encrypted audio signal is encoded in accordance with AAC, the signal of the previous frame of the speech section (the signal of the non-speech section) is inserted into the speech section. As a result, the signal component of the speaker's voice is excluded from the voice section. On the other hand, no special processing is applied to the non-voice section. Therefore, for example, data representing the second processed audio signal including the signals of the analog waveform 333 in FIG. 11C and the analog waveform 341 in FIG. 11D is transmitted to the browsing PC 103 and provided in the browsing PC 103. The second processed audio signal is reproduced and output from a reproduction output unit including a speaker.

  When the browsing PC 102 issues a transmission request to the server 3 to transmit an audio signal corresponding to the special file 300 in the server 3 to the browsing PC 102, the main control unit 61 of the server 3 The authority to be given to the viewing PC 102 is recognized based on the public level information of the special file 300 and the public management relation information in the public management memory 65. As described above, the authority to be given to the browsing PC 102 is the second authority. In this case, the audio signal processing unit 62 (see FIG. 8) of the server 3 reads the encrypted audio signal and the decryption information in the special file 300 from the server HDD 64, and decrypts the encrypted audio signal based on the decryption information. To restore the original audio signal. Thereafter, based on the voice section information, a predetermined processing is performed on the original audio signal in the voice section to create a first processed audio signal that cannot identify a speaker in the voice section.

  Specifically, a processing process is performed so that the voice characteristics (for example, voice color) of the speaker in the voice section of the first processed audio signal are different from those of the original audio signal. However, the processing is not performed so that the utterance contents cannot be specified. A known method can be adopted as a method of changing the characteristics of the voice. For example, the voice color (pitch) of the speaker can be changed by preparing a buffer memory for writing the original audio signal in the voice section and changing the writing frequency and the reading frequency to the buffer memory. Further, when the first processed audio signal is created, no special processing is applied to the non-voice section. Therefore, for example, data representing the first processed audio signal including the signal of the analog waveform 332 in FIG. 11B and the analog waveform 341 in FIG. 11D is transmitted to the viewing PC 102 and provided in the viewing PC 102. A first processed audio signal is reproduced and output from a reproduction output unit including a speaker.

  If it carries out as mentioned above, it is possible to introduce the mechanism which protects the privacy regarding an audio signal in websites, such as SNS and a blog. The user on the public side can simply enjoy the privacy protection effect simply by setting the public level information (or simply using the public level information automatically set by the recording device 1). .

  In addition to public control based on public level information, public control using an authentication code can be performed. In this case, for example, the authorization management information in the header area 301 of the special file 300 includes an authentication code that can be set on the recording device 1 or the user PC 2. For example, when the user of the user PC 2 wants to provide the original audio signal to the user of the browsing PC 103 who has only the third authority via the server 3, the user of the user PC 2 gives the user of the browsing PC 103 the above-mentioned Tell your authentication code as a password. When the user of the browsing PC 103 outputs an audio signal transmission request corresponding to the special file 300 along with the password to the server 3, the main control unit 61 of the server 3 sends the password sent from the browsing PC 103. And the authentication code stored in the special file 300 in the server HDD 64 are verified, and if they match, the original audio signal is restored from the encrypted audio signal and the decryption information in the special file 300 to obtain the original Data representing the audio signal is transmitted to the browsing PC 103 (if it does not match, the transmission is not performed). Thereby, the original audio signal is reproduced and output from the reproduction output unit including the speaker provided in the browsing PC 103.

  Instead of transmitting the password, the ID number of the browsing PC 103 and an authentication code may be linked. That is, for example, an authentication code is set on the recording device 1 or the user PC 2 so that the authentication code in the header area 301 is the same as the ID number of the viewing PC 103, and a special file including the authentication code is set. 300 is uploaded to the server 3. When the user of the browsing PC 103 outputs an audio signal transmission request corresponding to the special file 300 to the server 3, the main control unit 61 of the server 3 determines the ID number of the browsing PC 103 and the authentication code of the header area 301. If matching is confirmed, the original audio signal is restored from the encrypted audio signal and the decryption information in the special file 300, and data representing the original audio signal is transmitted to the viewing PC 103 (must match). If not, the transmission is not performed).

  In addition, there are various modifications, but the modifications that can be used are listed below.

  Modification 1: The content described in FIG. 10 according to a prescribed description format may be used as the public level information. For example, the content shown in FIG. 10 is “1” in the entire file management system shown in FIG. You may make it prescribe | regulate that it is. In this case, it is sufficient to describe “1” as the public level information in the header area 301. In this case, of course, a character string other than 1 is assigned to the public level information different from the public level information shown in FIG. In addition to this, it is possible to represent the public level information by an arbitrary description method defined in the file management system. Further, the relationship between each public relationship and each authority shown in FIG. 10 is an example, and the user can change it in various ways.

  Modification 2: In the above example, in response to a transmission request from a viewing PC having the first, second, and third authorities, the original audio signal corresponding to FIG. ) And the second processed audio signal corresponding to FIG. 11C are transmitted merely as examples, and various modifications can be made. For example, the original audio signal, the first processed audio signal, and the first processed audio signal may be transmitted in response to a transmission request from the viewing PC having the first, second, and third authorities, respectively. However, the original audio signal, the original audio signal, and the first processed audio signal may be transmitted, respectively. It is also possible that no audio signal is transmitted in response to a transmission request from a viewing PC having the third authority.

  Modification 3: In the above example, the disclosure method is classified into three stages according to the disclosure level information, but the number of stages is arbitrary. It is possible to classify the disclosure method into four or more stages according to the SNS or the like, or the classification may be limited to classification up to two stages. Similarly, the number of authority classifications can be other than three. As illustrated in the second modification, in response to a transmission request from the viewing PC having the first, second, and third authorities, the original audio signal, the first processed audio signal, and the first processed audio signal, respectively. As a result, the release method is classified into two stages.

<< 4th Example >>
Next, a fourth embodiment will be described. The fourth embodiment corresponds to a modification of the third embodiment, and the items described in the third embodiment are also applied to the present embodiment (and the items described in the first embodiment are also applied). .

  In the fourth embodiment, it is assumed that the recording apparatus 1 in FIG. 1 has a speaker recognition function. The speaker recognition function is realized by a speaker recognition unit provided in the audio signal processing unit 12 of FIG. The speaker recognizing unit determines whether or not the speaker (speaker) in the voice section matches a registered speaker registered in advance based on the original audio signal given from the microphone unit 11.

  For example, an utterance content independent type speaker recognition process for performing speaker recognition with an arbitrary word is used. Any known method can be adopted as a method for realizing the speaker recognition processing. A method for speaker recognition will be briefly described. FIG. 12 shows a block diagram of a speaker recognition unit for performing known speaker recognition processing.

  First, speaker registration is performed before speaker recognition. At the time of speaker registration, the audio signal output from the microphone unit 11 is supplied to the feature amount extraction unit 71. The feature quantity extraction unit 71 extracts feature quantities such as cepstrum and pitch included in speech such as sentences generated by the speaker. At the time of speaker registration, the feature amount is given to the speaker model creation unit 72. The speaker model creation unit 72 creates a speaker speech model (hereinafter referred to as a registered speaker model), for example, a hidden Markov model, based on the extracted feature quantity. The registered speaker model is recorded in the speaker model recording unit 73.

  At the time of speaker recognition, the speech of the recognition target speaker (current speaker) included in the original audio signal from the microphone 11 unit is supplied to the feature amount extraction unit 71. A feature quantity extraction unit 71 extracts feature quantities such as cepstrum and pitch included in speech such as sentences generated by the recognition target speaker. At the time of speaker recognition, the feature amount is given to the likelihood calculating unit 74. The likelihood calculating unit 74 compares the registered speaker model recorded in the speaker model recording unit 73 with the feature amount corresponding to the recognition target speaker, and calculates the likelihood (similarity). If the likelihood is larger than a predetermined threshold, it is determined that the recognition target speaker matches the registered speaker. Otherwise, it is determined that the recognition target speaker is different from the registered speaker.

  FIG. 13 shows a schematic diagram of an original audio signal assumed in this embodiment. The entire section of the original audio signal includes a voice section and a non-voice section, and the voice section is formed from a plurality of sections that are separated from each other in time. Now, as shown in FIG. 13, considering a case where a speech section includes three sections separated from each other in time, the three sections will be referred to as first, second, and third element sections. Then, by using the speaker recognition unit as shown in FIG. 12, the voice speaker (speaker) included in the first and second element sections matches the registered speaker, and the third element Assume that it is determined that the voice speaker (speaker) included in the section is different from the registered speaker. Hereinafter, a speaker (speaker) different from the registered speaker is referred to as a non-registered speaker.

  A special file assumed in this embodiment is called a special file 400, and its data structure is shown in FIG. The data of the encrypted audio signal is stored in the main body area of the special file 400 stored in the memory card 13 of FIG. 1, and the voice section information, the decryption key information, and the authority management information are stored in the header area of the special file 400. Is done.

  The voice section information of the special file 400 includes information representing the speaker in each element section. In the case of the present example, the voice section information not only indicates which section of all sections of the original audio signal (or encrypted audio signal) is the voice section, but also the first and second element sections. It also represents that the speaker is a registered speaker and the speaker in the third element section is a non-registered speaker. Then, as in the third embodiment, public level information is included in the authority management information of the special file 400, and further, this public level information includes element intervals corresponding to registered speakers and element intervals corresponding to non-registered speakers. And can be set separately.

  The public level information for the element section corresponding to the registered speaker is referred to as registered speaker public level information, and the public level information for the element section corresponding to the non-registered speaker is referred to as non-registered speaker public level information. The registered speaker public level information and the non-registered speaker public level information define the relationship between each public relationship and each authority as described with reference to FIG. The user can individually set the registered speaker public level information and the unregistered speaker public level information on the recording device 1 or the user PC 2. In this embodiment, it is assumed that the public management memory 65 (FIG. 8) of the server 3 stores the public management relation information shown in FIG.

  For example, the voice of a registered speaker (for example, the owner of the recording apparatus 1) may be disclosed to a friend of a friend, but the conversation of a speaker talking around the registered speaker is disclosed to a friend other than the friend. If not, for example, the registered speaker public level information shown in FIG. 15A and the unregistered speaker public level information shown in FIG. 15B are set.

The set registered speaker public level information gives the first, first, and second authorities to the viewing side PC having the first, second, and third public relations with the user PC 2, respectively. I will tell you. This instruction is an instruction only for the first and second element sections in which the registered speaker is speaking.
The set public level information for the non-registered speaker gives the first, third, and third authorities to the viewing-side PC having the first, second, and third public relations with the user PC 2, respectively. Instruct to give. This instruction is an instruction only for the third element section in which the unregistered speaker is speaking.

  After this setting, when the special file 400 is uploaded to the server 3 via the user PC 2 and the communication network 4 in FIG. 6, it is stored in the server HDD 64 in FIG.

  When a transmission request for the special file 400 in the server 3 is output from each browsing PC (101 to 103), the main control unit 61 of the server 3 determines the public level information and the public management relationship of the special file 400 in the server HDD 64. Based on the information, the authority to be given to each browsing PC (101 to 103) is recognized. Then, based on the recognized authority and the audio section information of the special file 400, the transmission contents for each browsing PC are controlled.

  In the case of the present example, the main control unit 61 gives the first authority to the browsing PC 101 for all of the first to third element sections. Therefore, all the encrypted audio signals in the first to third element sections are correctly decrypted, and the decrypted audio signals (that is, all of the original audio signals) are transmitted to the viewing PC 101.

  The main control unit 61 gives the first authority to the viewing PC 102 with respect to the first and second element sections, and gives the third authority with respect to the third element section. Therefore, the encrypted audio signal in the first and second element intervals is correctly decrypted, and the original audio signal in the first and second element intervals is transmitted to the viewing PC 102. However, for the third element section, a signal that cannot specify the utterance content is transmitted to the viewing PC 102 instead of the original audio signal (see FIG. 11C). Transmission control according to these is also performed for the browsing PC 103. In the non-speech section, as in the third embodiment, the same audio signal as the audio signal at the time of recording is transmitted to each viewing PC (101 to 103).

  By performing the processing as described above, it is possible to perform public control according to the speaker, and fine privacy protection is possible.

  When there are a plurality of registered speakers, public level information may be set for each registered speaker.

[Distinction between multiple unregistered speakers]
Even when there are a plurality of non-registered speakers, it is preferable that public level information can be set for each non-registered speaker. This will be explained. Assume that there are first and second unregistered speakers different from each other as unregistered speakers. Also, ignore the registered speaker. In this case, the speaker recognition unit according to the present embodiment distinguishes whether the speaker in the voice section is the first or second non-registered speaker. A known technique can be applied to this distinction technique. For example, at the time of speaker recognition, the speech of the recognition target speaker (current speaker) included in the original audio signal from the microphone 11 unit is supplied to the feature amount extraction unit 71, and the sentence generated by the recognition target speaker, etc. The feature amount extraction unit 71 extracts feature amounts such as cepstrum and pitch included in the voice. Based on this feature amount, the speaker recognition unit can determine whether or not the speaker in a certain section is the same as the speaker in another section.

  Also in the present example, the above-described first to third element sections are assumed (see FIG. 13). And, for example, the speaker recognizer has the same voice speaker in the first and second element sections, and the voice speaker in the first and second element sections and the voice in the third element section. Suppose that the speakers are different. Then, by the speaker recognition unit, the voice speaker included in the first and second element sections is the first non-registered speaker, and the voice speaker included in the third element section is the second speaker. It is determined that the speaker is an unregistered speaker.

  Then, information representing the speaker in each element section is included in the voice section information of the special file 400 (see FIG. 14). In the case of the present example, the voice section information not only indicates which section of all sections of the original audio signal (or encrypted audio signal) is the voice section, but also the first and second element sections. It also represents that the speaker is the first unregistered speaker and the speaker in the third element section is the second unregistered speaker. Then, as in the third embodiment, the public level information is included in the authority management information of the special file 400, and the public level information can be set separately for each speaker (in other words, the public level). Information can be set separately for the element section corresponding to the first non-registered speaker and the element section corresponding to the second non-registered speaker).

  In the case of the present example, as public level information for the first and second non-registered speakers, first and second non-registered speaker public level information are provided, respectively. The first public level information for non-registered speakers is treated as public level information for the first and second element sections spoken by the first non-registered speaker, and is disclosed for the second non-registered speaker. The level information is handled as public level information for the third element section spoken by the second non-registered speaker. The user can individually set the first and second unregistered speaker public level information on the recording device 1 or the user PC 2. The operation of the server 3 according to this setting content is the same as described above.

  Note that the method of setting the public level information for each non-registered speaker can be performed separately from the method of distinguishing the registered speaker from the non-registered speaker.

[Sound source separation]
In an actual conversation, there may be a plurality of speakers in the same section (a plurality of people may speak at the same time). In consideration of this, the above-described content may be combined with sound source separation processing. This will be described.

  By applying sound source separation processing to a section in which a plurality of speakers are speaking at the same time, it is possible to distinguish and recognize each speaker in the section. In the sound source separation process, different speakers are regarded as different sound sources. In order to perform sound source separation, for example, the microphone unit 11 in FIG. 1 is formed by a plurality of microphones arranged at different positions, and the delay amount between the output signals of the microphones and the output signals of the microphones are separated. The sound source is separated from the difference in signal level. Since the processing content of the sound source separation itself is known, a detailed description is omitted. If the sound source can be separated, a plurality of different speakers can be separated and recognized.

  For example, consider a case where the first speaker and the second speaker are speaking simultaneously in the first element section in FIG. Assume that the first and second speakers are first and second sound sources, respectively. The voices of the first and second speakers are referred to as first and second voices, respectively. In this case, the speaker recognition unit according to the present embodiment performs sound source separation processing on the first element section, thereby separating the sound sources. That is, the first sound from the first sound source (the signal component of the first sound) and the second sound from the second sound source (the signal component of the second sound) included in the first element section. Isolate. Thereafter, the speaker recognition unit performs the above-described speaker recognition for each voice obtained by the separation.

  Similar processing is performed for the second and third element sections in FIG. Thus, for example, the first and second non-registered speakers are speaking in the first element interval, only the first non-registered speaker is speaking in the second element interval, and the third Assume that it is determined that only the second unregistered speaker is speaking in the element section. This determination result is included in the audio section information of the special file 400 (see FIG. 14). Then, as in the third embodiment, the public level information is included in the authority management information of the special file 400, and the public level information can be set separately for each speaker.

  In the case of the present example, as public level information for the first and second non-registered speakers, first and second non-registered speaker public level information are provided, respectively. The first public level information for non-registered speakers is treated as public level information for the first and second element sections spoken by the first non-registered speaker, and is disclosed for the second non-registered speaker. The level information is handled as public level information for the first and third element sections spoken by the second unregistered speaker. The user can individually set the first and second unregistered speaker public level information on the recording device 1 or the user PC 2.

  The operation of the server 3 according to this setting content is the same as that described above, but the first and second unregistered speaker public level information competes for the first element section. Either one is used preferentially. For example, the first unregistered speaker public level information “instructs the viewing side PC having the third public relationship with the user PC 2 to give the first authority” If the public level information for the non-registered speaker 2 “instructs the viewing-side PC having the third public relationship with the user PC 2 to give the third authority”, When the browsing PC 103 having the third public relationship among them outputs a transmission request for the special file 400 in the server 3 to the server 3, the server 3 operates as follows.

  The server 3 compares the first authority indicated by the first non-registered speaker public level information with the third authority specified by the second non-registered speaker public level information, and determines the authority. Select the one with the larger value. In the case of this example, the third authority is selected. Therefore, for the first element section, the server 3 transmits a signal such that the utterance content cannot be specified instead of the original audio signal to the viewing PC 103 (see FIG. 11C). By processing in this way, the privacy of the second unregistered speaker is appropriately protected.

<< 5th Example >>
Next, a fifth embodiment will be described. By adding a reproduction function to the recording apparatus 1 of FIG. 1, an audio signal recording / reproducing apparatus can be formed. FIG. 16 shows an internal block diagram of the audio signal recording / reproducing apparatus 6 (hereinafter abbreviated as “recording / reproducing apparatus 6”). The recording / reproducing apparatus 6 includes the recording apparatus 1 of FIG. 1 and further includes an audio signal processing unit 16 and a reproduction output unit 17 including a speaker. The recording apparatus 1 included in the recording / reproducing apparatus 6 is the same as that described in the above embodiments.

  At the time of reproduction, the audio signal processing unit 16 reads the encrypted audio signal and the decryption information from the special file stored in the memory card 13 under the control of the main control unit 14, and encrypts based on the decryption information The original audio signal is restored by decoding the audio signal. Then, by supplying the restored original audio signal to the reproduction output unit 17, the original audio signal is reproduced and output from the reproduction output unit 17.

<< Sixth Example >>
Next, a sixth embodiment will be described. An imaging device can be formed by adding a photographing function to the recording / reproducing device 6 of FIG. FIG. 17 shows an internal block diagram of the imaging device 7. The imaging device 7 includes the recording / reproducing device 6 of FIG. 16, and further includes an imaging unit 18, a video signal processing unit 19, and a display unit 20. The imaging device 7 is a digital video camera that can capture still images or moving images.

  The imaging unit 18 includes an imaging device such as a CCD (Charge Coupled Devices) image sensor or a CMOS (Complementary Metal Oxide Semiconductor) image sensor, an optical system, and a diaphragm, and converts an optical image of a subject into an electrical signal. To obtain an image corresponding to the optical image. The video signal processing unit 19 generates a video signal representing the acquired image, performs a predetermined compression process on the video signal, and sends the video signal to the memory card 13. The video signal from the video signal processing unit 19 is recorded on the memory card 13 when a still image or a moving image is captured and recorded.

  In particular, when capturing and recording a moving image, the encrypted audio signal generated by the audio signal processing unit 12 and the video signal from the video signal processing unit 19 (that is, an image corresponding to the image acquired by the imaging unit 18). Data) are associated with each other and stored in one file. That is, the encrypted audio signal and the video signal are stored in the main body area of the special file described above. At this time, in connection with the privacy protection method for the audio signal, some processing may be applied to the image data stored in the special file (for example, the face area is subjected to mosaic processing or the like and then special processing is performed). Save to file).

  The display unit 20 displays the image acquired by the imaging unit 18 at the current time or the image represented by the video signal recorded on the memory card 13.

  Note that the audio signal processing unit 16 and the reproduction output unit 17 can be omitted from the imaging device 7.

<< Seventh Embodiment >>
Next, a seventh embodiment will be described. In the seventh embodiment, a method for protecting privacy for an audio signal that is not scheduled to be disclosed via the communication network 4 will be described.

  A method for protecting privacy between a plurality of recording / reproducing apparatuses will be described. Assume that there are two recording / reproducing apparatuses 6 and 6a as shown in FIG. The recording / reproducing apparatus 6 in FIG. 18 is the same as that shown in FIG. The recording / reproducing apparatus 6 a is a recording / reproducing apparatus having the same configuration as the recording / reproducing apparatus 6. Since the internal block diagram of the recording / reproducing apparatus 6a is the same as that of FIG. 16, overlapping illustration is omitted.

  Different recording codes are allocated to the recording / reproducing apparatuses including the recording / reproducing apparatuses 6 and 6a. This unique code is, for example, a serial number assigned to each recording / reproducing apparatus. For example, at the time of shipment of each recording / reproducing apparatus, the above unique code is stored in a nonvolatile memory (not shown) provided in the recording / reproducing apparatus (6 or 6a). Now, the unique code assigned to the recording / reproducing apparatus 6 is called a first unique code, and the unique code assigned to the recording / reproducing apparatus 6a is called a second unique code. As is clear from the above description, the first unique code and the second unique code are different from each other.

  In the present embodiment, it is assumed that the authority management information of the special file includes an authentication code, and the user cannot change the authentication code. Each recording / reproducing device (6, 6a) writes the unique code assigned to it in the header area of the special file as an authentication code.

  In the present embodiment, each recording / playback device (6, 6a) is installed with browsing software for a special file, and each recording / playback device (6, 6a) is stored in the special file on the browsing software. Data is read (assuming that data in a special file cannot be read without using the browsing software). The browsing software operates on the main control unit 14 in FIG.

  Now, consider a case where the original audio signal is acquired in the recording / reproducing apparatus 6 and the special file 430 corresponding to the original audio signal is stored in the memory card 13 of the recording / reproducing apparatus 6 (see FIG. 18). The special file 430 has the same data structure as that of the special file 300 in FIG. 2, but the first unique code assigned to the recording / reproducing apparatus 6 is written as an authentication code in the header area of the special file 430. It will be.

  The browsing software collates the authentication code written in the header area of the special file 430 with the unique code of the recording / playback apparatus in which the browsing software is installed, and only when the matching is confirmed, Based on the information, the encrypted audio signal in the special file 430 is decrypted, and the original audio signal obtained by the decryption is reproduced and output by the recording / reproducing apparatus in which the browsing software is introduced. The main control unit 14 includes a verification unit that performs verification between the authentication code and the unique code, and a determination unit that determines whether the encrypted audio signal is decoded and whether the original audio signal is reproduced and output based on the verification result. Will be realized.

  Specifically, the following operation is performed in the recording / reproducing apparatus 6. When the user of the recording / reproducing apparatus 6 tries to reproduce and output an audio signal corresponding to the special file 430, an operation for instructing reproduction output is performed on the operation unit 15. When this operation is performed, the browsing software (that is, the main control unit 14 of the recording / reproducing apparatus 6) reads the authentication code written in the header area of the special file 430 from the memory card 13 and is assigned to the recording / reproducing apparatus 6. The unique code is read from the non-volatile memory or the like, and the read authentication code and the unique code are collated. In this case, since the two match, the browsing software (that is, the main control unit 14 of the recording / reproducing apparatus 6) permits the decryption of the encrypted audio signal and the reproduction output of the original audio signal. Therefore, the audio signal processing unit 16 of the recording / reproducing apparatus 6 decrypts the encrypted audio signal in the special file 430, and the original audio signal obtained by the decryption is reproduced and output from the reproduction output unit 17 of the recording / reproducing apparatus 6. The

  On the other hand, when the memory card 13 storing the special file 430 is attached to the recording / reproducing apparatus 6a and the user of the recording / reproducing apparatus 6a tries to reproduce and output an audio signal corresponding to the special file 430, the recording / reproducing apparatus 6a Operation like this is performed. When the recording / reproducing apparatus 6a is operated to instruct reproduction output, the browsing software (that is, the main control unit 14 of the recording / reproducing apparatus 6a) uses the authentication code written in the header area of the special file 430 to the memory card 13. The unique code assigned to the recording / reproducing device 6a is read from the nonvolatile memory or the like, and the read authentication code and the unique code are collated. In this case, since the two do not match, the browsing software (that is, the main control unit 14 of the recording / reproducing apparatus 6a) prohibits the decryption of the encrypted audio signal and the reproduction output of the original audio signal. In this case, for example, the encrypted audio signal is supplied to the reproduction output unit 17 of the recording / reproduction device 6a as it is. In this way, the user of the recording / reproducing apparatus 6a cannot hear the human voice in the voice section. Alternatively, no audio signal may be given to the reproduction output unit 17.

  Of the recording / reproducing apparatuses 6 and 6a, only the recording / reproducing apparatus 6 may be configured to cancel the above-described processing for permission / prohibition of decryption of the encrypted audio signal. This cancellation is executed on the browsing software on the condition that the authentication code and the unique code match (therefore, the recording / reproducing apparatus 6a cannot execute this cancellation). After the operation for instructing the cancellation is performed on the recording / reproducing apparatus 6, the original audio signal corresponding to the special file 430 can be restored and reproduced on the recording / reproducing apparatus 6a.

  Moreover, although the operation | movement between several recording / reproducing apparatuses was demonstrated, the same operation | movement can also be performed between several imaging devices containing a recording / reproducing apparatus.

  Next, a privacy protection method on the PC will be described using the special file 430 as an example. Now, as shown in FIG. 19, it is assumed that there is a personal computer 2a (hereinafter referred to as PC2a) different from the user PC2 in addition to the user PC2. The PC 2a has the same configuration as the user PC 2. Since the internal block diagram of the PC 2a is the same as that of FIG. 7, overlapping illustration is omitted. The special file 430 is provided to the user PC2 and the PC2a.

  In the present embodiment, dedicated software for special files is introduced into the user PC2 and PC2a, and playback devices (audio signal playback devices) including the user PC2 and PC2a that can access the special file are on the dedicated software. However, it is assumed that each data in the special file cannot be read and edited. The program representing the dedicated software is stored in the memory 48 of FIG.

  A PC registration code can be registered in the dedicated software. This registration is performed when the dedicated software is introduced into the playback device (for example, the user PC 2 and the PC 2a). When the user of the recording / reproducing device 6 and the user PC 2 introduces the dedicated software to the user PC 2, the user assigns the first unique code assigned to the recording / reproducing device 6 to the user PC 2. It is registered on the dedicated software of the user PC 2 as a registration code. On the other hand, when the user of the recording / reproducing apparatus 6a and the PC 2a introduces the dedicated software to the PC 2a, the second unique code assigned to the recording / reproducing apparatus 6a is given to the PC 2a so that the second unique code is used for the PC. It is registered on the dedicated software of the PC 2a as a registration code. The first unique code is unknown to the users of the recording / reproducing apparatus 6a and the PC 2a.

  The dedicated software collates the authentication code written in the header area of the special file 430 (in this case, the first unique code) with the registration code for PC registered in the dedicated software. Only when it is confirmed, the encrypted audio signal in the special file 430 is decrypted, and the original audio signal obtained by the decryption is reproduced and output from the reproduction output unit of the reproduction apparatus in which the dedicated software is installed. The decryption of the encrypted audio signal is performed by, for example, the audio signal processing unit 42 (decryption processing unit) in FIG. The main control unit includes a verification unit that performs verification between the authentication code and the PC registration code, and a determination unit that determines whether the encrypted audio signal is decoded and whether the original audio signal is reproduced and output based on the verification result. 41 is realized.

  Specifically, the following operation is performed in the user PC 2. When the user of the user PC 2 tries to reproduce and output an audio signal corresponding to the special file 430, an operation for instructing reproduction output is performed on the PC operation key 47. When this operation is performed, the dedicated software (that is, the main control unit 41 of the user PC 2) compares the authentication code written in the header area of the special file 430 with the PC registration code registered in the dedicated software of the user PC 2. . In this case, since they match, the dedicated software (that is, the main control unit 41 of the user PC 2) permits the decryption of the encrypted audio signal and the reproduction output of the original audio signal. Therefore, the encrypted audio signal in the special file 430 is decrypted in the user PC 2 and the original audio signal obtained by the decryption is reproduced and output from the reproduction output unit 46 of the user PC 2. In addition, the user PC 2 is allowed to edit the original audio signal.

  On the other hand, when the user of the PC 2a tries to reproduce and output an audio signal corresponding to the special file 430, the following operation is performed in the PC 2a. The user of the PC 2a performs an operation for instructing the reproduction output on the PC operation key 47 of the PC 2a. When this operation is performed, the dedicated software (that is, the main control unit 41 of the PC 2a) collates the authentication code written in the header area of the special file 430 with the PC registration code registered in the dedicated software of the PC 2a. In this case, since they do not match, the dedicated software (that is, the main control unit 41 of the PC 2a) prohibits the decryption of the encrypted audio signal and the reproduction output of the original audio signal. In this case, for example, the encrypted audio signal is supplied to the reproduction output unit 46 of the PC 2a as it is. In this way, the user of the PC 2a cannot hear the human voice in the voice section. Alternatively, no audio signal may be given to the reproduction output unit 46.

  It should be noted that only the user PC2 out of the user PC2 and PC2a may be able to cancel the processing as described above for permission / prohibition of decryption of the encrypted audio signal. This cancellation is executed on the dedicated software on condition that the authentication code matches the PC registration code (and therefore cannot be executed by the PC 2a). After the user PC2 is instructed to cancel, the original audio signal corresponding to the special file 430 can be restored and reproduced on the PC 2a.

  By performing the processing as described above, the original audio signal is not reproduced and output except for the recording / reproducing apparatus 6 or the user PC 2, so that the memory card 13 is lost or stolen, or the computer virus or file exchange software is abused via the network. Even if the special file 430 is leaked, privacy is protected.

<< Eighth Example >>
The special file generated in each of the above-described embodiments may be copied (replicated) to a recording medium other than the memory card 13. However, a mechanism for protecting the privacy of this copy may be introduced. it can. In this embodiment, it is assumed that the special file can be copied only on specific duplication software. For example, the duplication software is installed in the user PC 2 and operates on the user PC 2.

  In this embodiment, it is assumed that the authority management information of the special file includes authority level information, and the user cannot change the authority level information. The user can give an authentication code as a password to the special file created on the recording apparatus 1 in FIG. 1, the recording / reproducing apparatus 6 in FIG. 16, or the imaging apparatus 7 in FIG. This assignment is performed on the recording device 1, the recording / reproducing device 6, the imaging device 7, or the user PC 2. FIG. 20 shows the data structure of the special file 500 after the assignment. It is not essential to give an authentication code.

  The header area of the special file 500 stores voice section information, decryption key information, and authority management information, and the authority management information includes the authority level information and the authentication code. Data of the encrypted audio signal is stored in the main body area of the special file 500. The authority level information indicates any of the authority levels classified into a plurality of stages. Now, it is assumed that the authority level information takes any value of “1”, “2”, or “3”, and the authority level is classified into three levels. Of course, the authority level may be classified by the number of stages other than three stages. It is assumed that the authority level is the highest when the authority level information is “1”, and the authority level decreases as the numerical value of the authority level information increases.

  The authority level information is initially “1”. That is, when the special file 500 is created and saved in the memory card 13, “1” is written as the authority level information.

  When the special file 500 is copied on the copy software, only the authority level information is changed from that of the copy-source special file. Specifically, the value of authority level information in the copy-destination special file is increased by 1 or more with respect to the value of authority level information in the copy-source special file. For example, when the authority level information in the copy source special file is “1”, the authority level information in the copy destination special file is “2”, and the authority level information in the copy source special file is “2”. At this time, the authority level information in the copy-destination special file is set to “3”. However, if the user who wants to duplicate gives the above-mentioned authentication code to the device (for example, user PC 2) in which the duplication software is introduced, the authority level information is not changed. And

  In the present embodiment, playback devices (audio signal playback devices) that can access the special file 500, including the recording / playback device 6, the imaging device 7, and the user PC 2, perform playback control according to authority level information. For the sake of concrete explanation, consider a case where the playback device is the user PC 2.

  For example, when instructed to reproduce and output an audio signal corresponding to a special file, the user PC 2 refers to authority level information in the special file 500 given to the user PC 2. Then, the following operation is performed according to the authority level information.

  When the authority level information is “1”, the user PC 2 decrypts the encrypted audio signal in the special file 500 based on the decryption information in the special file 500, and uses the original audio signal obtained by the decryption as the user PC 2. The reproduction output unit 46 reproduces and outputs.

  When the authority level information is “2”, the user PC 2 restores the original audio signal from the encrypted audio signal based on the decryption information, and then performs a predetermined processing on the original audio signal in the voice interval based on the audio interval information. The first processed audio signal is created so that the speaker in the voice section cannot be identified. This first processed audio signal is the same as that described in the third embodiment, and can be created by the method described in the third embodiment (see FIG. 11B). The first processed audio signal is reproduced and output by the reproduction output unit 46 of the user PC 2.

  When the authority level information is “3”, the user PC 2 reads the encrypted audio signal in the special file 500, and based on the encrypted audio signal and the voice section information, the user PC 2 cannot specify the utterance content in the voice section. 2 Create a processed audio signal. This second processed audio signal is the same as that described in the third embodiment, and can be created by the method described in the third embodiment (see FIG. 11C). Then, the second processed audio signal is reproduced and output by the reproduction output unit 46 of the user PC 2.

  The recording medium containing the copied special file is initially delivered to an acquaintance or family, but may be passed on to unspecified people. Considering this, as described above, the authority level information is changed each time copying is repeated (the authority level related to reproduction is lowered). As a result, the sound is not reproduced in the copied special file. As a result, the possibility of voice information being distributed to unspecified persons is suppressed, and privacy can be protected. Further, by using an authentication code as a password, copying can be performed while maintaining the authority level. By using an authentication code, it is possible to distribute the same special file to acquaintances and family members.

<< Deformation, etc. >>
The specific numerical values shown in the above description are merely examples, and as a matter of course, they can be changed to various numerical values. As modifications or annotations of the above-described embodiment, notes 1 to 4 are described below. The contents described in each comment can be arbitrarily combined as long as there is no contradiction.

[Note 1]
In each of the above-described embodiments, it is described that only the original audio signal in the speech section is encrypted and the original audio signal in the non-speech section is not subjected to the encryption process. You may make it apply with respect to the original audio signal of both the area and a non-voice area. Also in this case, for example, with respect to the non-speech section, the original audio signal at the time of recording is reproduced and output on the reproduction device side regardless of the authority management information.

[Note 2]
Although an example in which voice segment information is used when decrypting an encrypted audio signal has been described, fast-forward playback or the like can be performed using this voice segment information. For example, after decrypting the original audio signal from the encrypted audio signal, the signal in the voice section of all sections of the original audio signal is cut out based on the voice section information, and only the signal of the cut out part is reproduced and output. Fast forward playback is possible. In addition, for example, it is also possible to reproduce the sound slowly by extending the extracted signal to the non-speech section.

[Note 3]
The recording apparatus 1 in FIG. 1, the recording / reproducing apparatus 6 in FIG. 16, and the imaging apparatus 7 in FIG. 17 can be realized by hardware or a combination of hardware and software. In particular, the functions of the main control unit 14 and the audio signal processing units 12 and 16 can be realized by hardware, software, or a combination of hardware and software.

  The user PC 2 in FIG. 7 and the server 3 in FIG. 8 can also be realized by hardware or a combination of hardware and software. In particular, the function of the main control unit 41 in FIG. 7 and the function of the main control unit 61 in FIG. 8 can be realized by hardware, software, or a combination of hardware and software. A block diagram of a part realized using software represents a functional block diagram of the part.

[Note 4]
For example, it can be considered as follows. The main control unit 14 shown in FIG. 1 and the like has a function as a recording control unit that records a special file on the memory card 13. In the user PC 2 of FIG. 7, the card slot 44 can function as a file input means for receiving a special file. Of course, the special file can also be provided to the user PC 2 by wired or wireless communication. Of course, the special file described above is an electronic file, and not only audio signal data but also image data can be stored in the electronic file.

1 is an internal block diagram of an audio signal recording apparatus according to a first embodiment of the present invention. It is a figure which shows the data structure of the special file preserve | saved at the memory card of FIG. FIG. 6 is an internal block diagram of the audio signal processing unit of FIG. 1 according to a second embodiment of the present invention. It is a figure for demonstrating the operation | movement content of the audio | voice / non-audio | voice discrimination | determination part of FIG. It is a figure for demonstrating the operation | movement content of the audio | voice / non-audio | voice discrimination | determination part of FIG. It is a whole block diagram of the file management system which concerns on 3rd Example of this invention. It is a schematic internal block diagram of the user PC of FIG. FIG. 7 is a schematic internal block diagram of the server of FIG. 6. It is a figure which shows the example of the content of the public management relationship information which prescribes | regulates the relationship between user PC of FIG. 6, and each browsing PC. It is a figure which shows the example of the content of the public level information in the special file preserve | saved at server HDD of the server of FIG. It is a figure which shows the audio signal transmitted to each PC for browsing from the server of FIG. It is a block diagram of the speaker recognition part which concerns on 4th Example of this invention. It is a schematic diagram of the original audio signal which concerns on 4th Example of this invention. It is a figure which shows the data structure of the special file which concerns on 4th Example of this invention. It is a figure which shows the example of the content of the public level information (a) for registration speakers, and the public level information (b) for non-registration speakers based on 4th Example of this invention. It is an internal block diagram of the audio signal recording / reproducing apparatus based on 5th Example of this invention. It is an internal block diagram of the imaging device which concerns on 6th Example of this invention. It is a figure which shows the two audio signal recording / reproducing apparatuses based on 7th Example of this invention. It is a figure which shows two PCs (personal computer) based on 7th Example of this invention. It is a figure which shows the data structure of the special file which concerns on 8th Example of this invention.

Explanation of symbols

1 Audio signal recording device 2 User PC
3 Server 6 Audio Signal Recording / Reproducing Device 7 Imaging Device 101, 102, 103 Viewing PC

Claims (12)

In an audio signal recording device,
Speech section detecting means for detecting a speech section including a signal component of human speech from all sections of the input original audio signal;
Encryption means for generating an encrypted audio signal from the original audio signal by performing an encryption process on the signal in the voice section of the original audio signal;
An audio comprising: recording control means for recording an electronic file in which the encrypted audio signal and decryption information for decrypting the encrypted audio signal are stored in association with each other in a recording means Signal recording device. The recording control means includes authority management information for switching permission / prohibition for decrypting the encrypted audio signal according to the decryption information and reproducing and outputting the original audio signal obtained by the decryption, 2. The audio signal recording apparatus according to claim 1, wherein the audio signal recording apparatus is further stored in the electronic file in association with the encrypted audio signal and the decryption information. The audio signal recording apparatus according to claim 1 or 2, wherein the decoding information includes voice section information indicating which section of the whole section is the voice section. The speech section is composed of a plurality of different element sections,
The audio signal recording apparatus further includes speaker recognition means for determining, for each element section, a match or mismatch between the voice speaker and a registered speaker registered in advance.
The decoding information includes speech section information that represents which section of the entire section is the speech section and also represents a discrimination result of the speaker recognition means for each element section,
The recording control means performs switching control of permission / prohibition for reproducing and outputting the original audio signal of each element section obtained by decrypting the encrypted audio signal of each element section in accordance with the decoding information. Authority management information for further storing in the electronic file in association with the encrypted audio signal and the decryption information,
The authority management information individually includes first authority management information for an element section including a signal component of the voice of the registered speaker, and second authority management information for other element sections. The audio signal recording apparatus according to claim 1. An audio signal recording / reproducing apparatus comprising the audio signal recording apparatus according to claim 2,
The authority management information includes an authentication code,
Unique codes different from each other between the audio signal recording / reproducing device and the other audio signal recording / reproducing device are given in advance to the audio signal recording / reproducing device,
The audio signal recording / reproducing apparatus includes:
Reproduction output means for reproducing and outputting an audio signal;
Decryption processing means for decrypting the encrypted audio signal based on the decryption information;
Collating means for collating the authentication code with the unique code for the audio signal recording / reproducing device;
Determining means for determining whether to permit reproduction output of the original audio signal obtained by decoding of the decoding processing means in the reproduction output means, based on the result of matching by the matching means;
An audio signal recording / reproducing apparatus, wherein the decoding processing means and the reproduction output means are controlled in accordance with a discrimination result of the discrimination means. In an imaging device that acquires an image according to a subject,
An image pickup apparatus comprising the audio signal recording apparatus according to any one of claims 1 to 4 or the audio signal recording / reproducing apparatus according to claim 5. Data of an encrypted audio signal obtained by performing encryption processing on a signal in a voice section including a signal component of a human voice in the original audio signal;
An electronic file, wherein data of decryption information for decrypting the encrypted audio signal is stored in association with each other. Data of authority management information for switching control of permission / prohibition for decrypting the encrypted audio signal according to the decryption information and reproducing and outputting the original audio signal obtained by the decryption is further provided. 8. The electronic file according to claim 7, wherein the electronic file is stored in association with the data of the digitized audio signal and the data of the decoding information. 9. The electronic file according to claim 2 or 8 is received from a provider device, and according to a transmission request from a terminal device that has a predetermined relationship with the provider device and includes playback output means for playing back and outputting an audio signal. An information providing device that transmits information based on the electronic file to the terminal device via a communication network,
A decryption processing means for decrypting the encrypted audio signal in the electronic file based on the decryption information in the electronic file;
When there is a transmission request, based on the authority management information in the electronic file and the relationship, it is determined whether or not transmission of the original audio signal obtained by decoding of the decoding processing means to the terminal device is permitted. And an information providing apparatus that controls transmission contents to the terminal device according to the determination result. Reproduction output means for reproducing and outputting an audio signal is provided,
11. A terminal device, wherein information based on the electronic file is received from the information providing device according to claim 10 via a communication network, and an audio signal based on the received information is reproduced and output by the reproduction output means. . An audio signal reproduction apparatus comprising: file input means for receiving the electronic file according to claim 2; and reproduction output means for reproducing and outputting an audio signal.
The authority management information in the electronic file includes an authentication code,
The audio signal reproduction device
Decryption processing means for decrypting the encrypted audio signal in the electronic file based on the decryption information in the electronic file;
Verification means for verifying the authentication code and the code registered in the audio signal reproduction device;
Determining means for determining whether to permit reproduction output of the original audio signal obtained by decoding of the decoding processing means in the reproduction output means, based on the result of matching by the matching means;
An audio signal reproducing apparatus, wherein the decoding processing means and the reproduction output means are controlled in accordance with a discrimination result of the discrimination means. In the electronic file recording method,
Data of an encrypted audio signal obtained by performing encryption processing on a signal in a voice section including a signal component of a human voice in the original audio signal;
A recording method of an electronic file, wherein data of decryption information for decrypting the encrypted audio signal is recorded in association with each other.

Images