KR0157666B1 - Audio scramble system, audio scramble apparatus and audio descramble apparatus - Google Patents

Abstract

The scrambler of the present invention has a voice signal as a processing target, and is composed of a detection device and an encryption device. ① The detection device detects the most significant bit of the sample data (the most significant bit with a different symbol from the MSB) and encrypts only the lower bits. ② The detection device compares the kinsoku code and some bits of the sample data, and the encryption device encrypts other than the compared bits only when the comparison result is inconsistent. (3) An audio signal composed of quantized data quantized after being normalized by amplitude information and amplitude information is subjected to processing. The detection device detects the position of the quantized data, and the encryption device encrypts only the quantized data.

Description

Voice scramble system, voice scrambler and voice descrambler

1 is a block diagram of a scramble system of the first embodiment.

2 is a block diagram of a scramble apparatus in the scramble system of the first embodiment.

3 is a block diagram of an encryption device of a random number device of a scramble device in the scramble system of the first embodiment.

4 is a block diagram of a descrambling apparatus in the scramble system of the first embodiment.

5 is an explanatory diagram of the processing of the inverting apparatus of the scramble apparatus in the scramble system of the first embodiment.

6 is an explanatory diagram of the processing of the detection apparatus of the randomization apparatus of the scramble apparatus in the scramble system of the first embodiment.

7 is an explanatory diagram of a process of a comparison device of a random number device of a scramble device in the scramble system of the first embodiment.

8 is a block diagram of an encryption device of a random number recovery device of a scramble device and a cryptographic decryption device of a random number recovery device of a scramble device in the scramble system of the first embodiment.

9 is a block diagram of the scramble system of the second embodiment.

10 is a block diagram of a scrambler of the scrambler system of the second embodiment.

11 is a block diagram of a descrambler of the scrambler system of the second embodiment.

* Explanation of symbols for main parts of the drawings

11, 91: digital speech generating device 12, 93: scrambled device

13, 94: transmission device 14, 95: transmission path

15, 96: receiver 16, 97: descrambler

17: reception processing device 18, 99: digital audio processing device

21: inversion device 22: randomization device

23: related information split device 31, 211: exclusive logic device

32: switch device 33: logical multiplication device

42: random number decoding device 81: separation device

82: block encryption device 83, 103: synthesis device

84: block encryption and decryption device 92: MPGE voice encoding device

98: MPEG audio decoding device 101: Splitter

102: scrambler 112: descrambler

212: total adding device 221: detecting device

222: comparison device 223: encryption device

423: encryption encoder

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a voice scramble system that scrambles at the transmitting side and descrambles at the receiving side for concealing the audio signal when transmitting or receiving or reproducing the voice signal by wire, wireless, or storage media.

A conventional voice scramble system is described, for example, in US Patent (5091941: Filed Oct. 31 1990, Ser. No. 607988). In this conventional audio scramble system, scramble is performed by only after the code bit of each sample of the digital audio signal is ignited. According to this, there is an effect that the sound after scrambled does not become an unusually loud sound. However, there is a problem that there is only one bit of secret for each sample, and it is relatively easy to decode it.

Another conventional voice scramble system is shown in Japanese Patent Laid-Open No. 63-87037. The transmitting side of this conventional voice scramble system extracts the amplitude data of the voice signal and performs scramble only when the amplitude data is below the set level. The receiving side receives the amplitude data and the scrambled voice and descrambles only when the amplitude data is below the set level. This has the effect that the scrambled voice does not become an unusually loud volume. However, this conventional apparatus has a problem in that it is necessary to transmit amplitude data in addition to voice, thus requiring a special transmission path.

In addition, a conventional encryption apparatus used in a communication system using a pattern with data for a control code is disclosed in Japanese Patent Laid-Open No. 4-68387. In this conventional encryption apparatus, a control table is converted into itself and other codes are converted into codes other than the control code in advance, and encrypted using them.

By the way, in the communication system, it is necessary to prevent the control code from being converted into another code or the other code into the control code in order to prevent miscontrol. Such control codes are called kinsoku codes. When a kinsoku code is not converted into another code by any processing, and a code other than the kinsoku code is not converted into a kinsoku code, this process is called kinsoku processing. According to the conventional encryption apparatus, it is possible to realize encryption processing involving kinsoku processing. This can prevent erroneous control in the communication system.

However, in the conventional encryption apparatus, there is a problem that a time for creating a conversion table in advance and a storage device for the conversion table are required, and the size and processing time of the device become large. In addition, there is a problem that encryption processing can only be realized by processing based on a conversion table.

This invention solves the problem in the conventional scramble system.

The first object of the present invention is to use any PCM digital voice data as a processing target, and does not need to transmit information other than the voice data, and has a relatively high safety and voice scramble that does not cause discomfort to the listener after the scrambled voice. To provide a system.

Further, the second object of the present invention is that when the data consisting of a plurality of codes having a kinsoku code is encrypted, kinsoku processing is possible, can be realized by a simple device configuration, and arbitrary encryption processing methods can be used. It is to provide a scrambled system.

A third object of the present invention is to have a plurality of subband data, each subband data being scrambled digital voice signal having quantized data after being normalized by amplitude information and amplitude information, and then scrambled voice. It is to provide a voice scramble system that does not cause discomfort to the listener.

The scramble system of the first invention is a voice scramble system which uses a digital voice signal for processing, wherein the voice scramble system includes a scrambler and a descrambler, and the scrambler has a MSB of sample data. ", The highest bit that becomes" 0 "among the bits other than the MSB, and the highest bit that becomes" 1 "among the bits other than the MSB when the MSB of the sample data is" 0 ". A detection device which detects as a bit and sets all or part of a bit position lower than the most significant bit as an encrypted data position, and an encryption device for encrypting the encrypted data position of the sample data; The descrambler is configured to determine the position of the encrypted data of the detection apparatus and the sample data. An audio scramble system comprising an encryption / decryption apparatus for performing inverse transformation encryption / decryption processing.

According to this, the position of the most significant bit of each sample data at the time of scramble does not change by the encryption process. The position of this most significant bit dominates the volume of the sample data. Therefore, even if the scrambled voice signal is reproduced, the voice signal of the loud volume is not abnormally loud, and thus the voice scramble can be realized without giving an extreme discomfort to the listener.

At the time of descrambling, since the position of the encrypted bit can be detected from the position of the most significant bit, it can be decrypted correctly.

A second invention of the present invention is a scramble system in which data consisting of a plurality of sample data including a kinsoku code is to be processed, wherein the scramble system includes a scramble device and a descramble device, and the scramble device includes: A detection device for comparing whether or not the sample data and the data of the comparison position of the kinsoku code correspond to each other with one or more bits of the sample data as a comparison position, and when the result of the comparison indicates an inconsistency, the sample And an encryption device which performs processing on data other than the comparison position of the data, and wherein the descrambler is configured to supply the data other than the comparison position of the sample data when the detection device and the result of the comparison indicate a mismatch. And an encryption and decryption apparatus for performing encryption and decryption processing, which is an inverse transformation of the encryption apparatus. It is a scrambled system.

According to this, when the data of the comparison position of the sample data and the kinsoku code coincide with each other, the sample data is not improved / decoded. Therefore, the sequential code is different from the kinsoku code or the kinsoku code is used. Other sample data do not become a kinsoku code. If the data of the comparison position between the sample data and the kinsoku code does not match, only the data other than the comparison position of the sample data is encrypted / decrypted, and the data of the comparison position is not processed. The data never becomes a kinsoku code. As described above, when the data consisting of a plurality of sample data containing the kinsoku code is processed, the kinsoku process can be realized. The encryption / decryption processing in the scramble system in the second invention only restricts the value of the processing, and the method itself of the encryption / decryption processing is arbitrary.

The third invention consists of a plurality of subband data, and each of the subband data is subjected to a digital speech code formed by generating quantized data after normalization by amplitude information and the amplitude information. In the scramble system, the scramble system comprises a scramble apparatus and a descramble apparatus, wherein the scramble apparatus performs encryption processing on the quantized data of all or part of the subband data, and encrypts the amplitude information. And the descrambler performs encryption and decryption processing on the quantized data of all or part of the subband data, and does not perform encryption and decryption processing on the amplitude information. Is the cancer in the encryption apparatus. A scramble system which is characterized in that the inversion of the screen processing.

As described above, the scramble process is performed only on the quantized data of each subband data, and the scramble process is not performed on the amplitude information. As a result, in each subband data, since the quantized data is randomized, the contents of speech are concealed, but the amplitude information is preserved, so that the volume of each subband data is not abnormally increased. Therefore, strange frequency components do not occur, and even when viewed as a whole, they do not become unusually large amplitudes. As described above, the voice scrambler that does not cause discomfort to the listener can be easily realized.

Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.

1 shows the configuration of a voice scramble system in the first embodiment of the present invention. In Fig. 1, reference numeral 11 denotes a digital voice generator, 12 denotes a scrambler, 13 denotes a transmitter, 14 denotes a transmission path, 15 denotes a receiver, and 16 denotes a descrambler. (17) denotes a reception processing apparatus, and (18) denotes a digital speech processing apparatus. The operation of the scramble system of the first embodiment configured in this way will be described below.

First, the digital speech producing apparatus 11 generates a digital speech signal composed of a plurality of sample data. The means for generating may be configured to A / D convert an analog audio signal introduced by a microphone or an analog audio signal reproduced from an analog cassette recorder and output the digital audio signal reproduced from a digital cassette recorder or a CD. What is necessary is just to output a digital audio signal, such as the structure which outputs a digital audio signal produced | generated by a computer.

At this time, each sample data is a two's complement binary number of two's complement display format sampled by a predetermined sampling frequency and quantized to n bits. Here, although n can generally think about the number of about 8-32, it is not limited to this, It is possible to take arbitrary finite numbers. In this embodiment, the case where n = 16 is shown as a typical number. The dynamic range may be a range that can be displayed with n bits. In the following description, when the hexadecimal display is shown by attaching Ox to the beginning, the typical value of the dynamic range assumes a range from Ox8001 to Ox7fff when n = 16. The predetermined sampling frequency may be 32 kHz, 44.1 kHz, 48 kHz, or any finite value. Typically used in the range of 16kHz to 96kHz.

The scrambler 12 then scrambles the digital audio signal. The operation of this scrambler 12 will be described in detail later.

Next, the transmitter 13 transmits the output of the scrambler 12 through the transmission path 14, and receives it in the receiver 15. FIG. Here, the transmission path 14 may be a wire such as an optical fiber, a coaxial cable or a telephone line, or may be wireless. The storage medium may be a magnetic tape, a magnetic disk, a compact disk, or the like. The transmitting device 13 assigns an error correction code to the digital audio data, converts it into a form suitable for the transmission path 14, and transmits. The transmitter 15 receives the data transmitted in this way, reproduces the digital audio data, performs a miscorrection correction process, and performs a process of substituting the erroneous sample data left uncorrectable with Ox8000.

Next, the descrambler 16 descrambles the digital audio signal. The descrambler 16 is an apparatus for inversely converting the scrambler 12, and the operation thereof will be described later in detail.

Next, the reception processing apparatus 17 performs an error interpolation process of replacing the code of Ox8000 in the sample data with the average value of the sample data before and after. In this case, Ox8000 is used as a control code for the purpose of displaying misleading sample data between the receiving device 15 and the receiving processing device 17. However, as long as it is outside the dynamic range, any code may be selected as the control code. In addition to the above-described purposes, the control code synchronizes between any device such as between the transmission device 13 and the reception device 15 or between the transmission device 13 and the reception processing device 17. It can be used for any purpose, for example.

By the way, when the control code of Ox8000 has been converted from the descrambling device 16 to another code, the error interpolation processing is not performed correctly in the reception processing device 17. Or, when another code is converted to Ox8000, error interpolation processing is performed on sample data without error. That is, Ox8000 is the kinsoku code explained in the conventional example, and in the descrambler 17, it is necessary to perform kinsoku processing using Ox8000 as the kinsoku code. In addition, since the process of the descrambler 17 is inversely transformed from the scrambler 12, the same kinsoku process must be performed in the scrambler 12 as well. The same also applies to the control codes used between different devices and for different purposes as indicated above.

Finally, the digital audio processing device 18 is a device that performs final processing such as reproduction and recording on the digital audio signal. For example, the configuration may be a D / A conversion of a digital audio signal and reproduced by a speaker, the configuration may be recorded on an analog cassette recorder, or the digital audio signal may be recorded on a digital cassette recorder or a magnetic disk. .

The operation of the scrambler 12 will be described in more detail with reference to the drawings. 2 shows the configuration of the scrambler 12. In Fig. 2, reference numeral 21 denotes an inverting device, reference numeral 22 denotes a randomization device, reference numeral 23 denotes an associated information divider, and reference numeral 211 denotes an exclusive logic device in an inversion device 21. It is a total addition device. In addition, in the randomization apparatus 22, 221 is a detection apparatus, 222 is a comparator, and 223 is an encryption apparatus.

The scrambler 12 inputs a digital audio signal composed of a plurality of 16 bits of sample data and scramble related information composed of a set of 15 bits of random numbers corresponding to each sample data, and performs processing in units of sample data. Subsequently, the operation of the scrambler 12 will be described with respect to the processing for one piece of sample data. In practice, the repetition processes a digital audio signal composed of a plurality of sample data.

First, the related information splitting apparatus 23 inputs a random number of 15 bits of scramble related information. The related information splitting apparatus 23 divides the random number of 15 bits, outputs 1 bit as an inversion control signal, and 14 bits as a random number control signal. Further, the 16-bit sample data of the input voice data is processed by the inverting device 21, and then by the random numbering device 22. Here, the inversion control signal is inputted to the inversion device 21 and the randomization control signal is input to the randomization device 22, and used for the control of processing. The processing in each apparatus is explained in full detail below.

First, the inversion apparatus 21 is demonstrated in detail. The inversion apparatus 21 inputs audio data and an inversion control signal.

First, the exclusive logic unit 211 exclusively sums the inversion control signal corresponding to the sample data on all bits of the sample data of the input audio signal and outputs the result. Next, the overall adding device 212 adds sample data of the data output from the exclusive logical summation device 41 and an inversion control signal corresponding to the sample data. Then, 16 bits of data excluding the pulling up to the 17th bit of the addition result are output as sample data after processing.

Here, in order to explain the operation of the inversion apparatus 21, an example of the inversion processing of the value of the sample data is shown in FIG. 5 shows a state of inversion of the sample data represented by binary numbers of two's complement display with a 3-bit code. Here, the dynamic range is from 101 (-3 in decimal) to 011 (3 in decimal). In this way, the inversion process refers to a process of selecting the intermediate value of the dynamic range, that is, the maximum value and the minimum value of the sample data as a reference value, and inverting the value of each sample data around the reference value, where 000 is the intermediate value of the dynamic range. Therefore, inversion processing is performed using 000 as a reference value. The same applies to the case of the binary number of the two's complement display with 16-bit sign used in the present embodiment.

In addition, also about the structure of the inversion apparatus 21, arbitrary structures which implement | achieve the inversion process like the example shown in FIG. 5 may be sufficient, and it is not limited to the structure shown in FIG. For example, it can also be configured using a ROM (Read Only Memory) in which an inversion result is recorded as an output for each address.

As described above, according to the processing of the inversion apparatus 21 of the present embodiment, when the input inversion control signal is 1, the result of inverting the sample data is output, and when it is 0, the input sample data is output as it is. That is, the sample data indicated by the inversion control signal is only inverted at the boundary of Ox0000, which is the center value of the dynamic area. Since the negative sample data is data that takes the value of the government, the inverted sample data as described above is only reversed by the government, and the absolute value of the amplitude does not change at all. In addition, the kinsoku process relating to the kinsoku code Ox8000 can be realized.

In this manner, according to the inversion apparatus 21, the kinsoku process using Ox8000 as the kinsoku code is possible without becoming an extreme large volume after the process. This effect can be obtained even when the scrambler 12 is composed only of the inverter 21.

Next, the operation of the randomization device 22 will be described. The randomization device 22 inputs sample data and a 14-bit randomization control signal corresponding to the sample data from the inversion device 21.

Prior to the description, first, the bit of the pseudonym is defined. The most significant bit is the most significant bit of a symbol different from the MSB (Most Siguificant Bit). When the MSB is "1", it indicates the most significant bit that becomes "0" among the bits other than the MSB, and the MSB is "0". Is displayed, the highest bit that becomes "1" among the bits other than the MSB is displayed. In other words, when the bit of the MSB and each bit other than the MSB is executed from the bits one bit lower than the MSB toward the lower bits in order, the bit having the symbol different from the first MSB first appears as the most significant bit. For example, the most significant bit of the 4-bit sample data "1101" whose left end is MSB is the third bit from the left, and the most significant bit of "0101" is the second bit from the left. The closer the most significant bit is to the MSB, the louder the volume level of the sample data is. Therefore, it can be said that the most significant bit is dominant with respect to the volume level of the sample data.

First, the detection device 221 detects the most significant bit of the 16-bit sample data, and generates a 14-bit selection signal in which all bits lower than the detected most significant bit are 1 and all other bits are 0. To print. However, the selection signal is not limited to this, and at least all of the most significant bits and the higher bits must be zero.

Next, the comparison device 222 inputs the audio signal and the selection signal output from the detection device 221. The comparison device 222 then compares the strict code with the upper two bits of the sample data and the bit at the position where the selection signal is zero. As a result of this comparison, a processing flag that is 0 if there is a perfect match and 1 if there is a bit that does not match is generated and output.

Here, the comparison device 222 may have a structure having a kinsoku code inside or a structure input from the outside.

Next, the encryption device 222 inputs a voice signal, a randomization control signal, a selection signal output from the detection device 221, and a processing flag output from the comparison device 222.

The configuration diagram of the encryption apparatus 223 is shown in FIG. In Fig. 3, reference numeral 310 denotes an exclusive logic device, 32 a switch device, and 33 a logical multiplication device. First, the logical multiplication device 33 inputs a selection signal and randomization control information. The logical product of the signal and the randomization control information is performed, and the result is output.Next, when the processing flag is 1, the switch device 32 outputs the output of the logical product device 33 as it is, and the processing flag is 0. In this case, 14 bits which are all 0s are outputted. Then, the exclusive logic unit 31 performs exclusive logic sum of the lower 14 bits of the sample data and the 14-bit output from the switch device 32. The upper 2 bits Is the upper 2 bits of the sample data, and the lower 14 bits output 16 bits of data which is 14 bits of the result of the exclusive logical sum.

The encryption device 223 is not limited to the configuration as shown in FIG. If the processing flag is 1 and the configuration is such that the sample data at the position where the selection signal is 1 is randomized, a configuration using any encryption scheme such as DES or RSA can be adopted.

The process of the randomization apparatus 22 shown above is demonstrated using drawing.

6 is a view for explaining the processing of the detection device 221 of the random number device 22 of the scrambler 12 of the first embodiment. In Fig. 6, reference numerals 61 and 62 denote sample data, reference numerals 611 and 621 denote most significant bits, reference numerals 612 and 622 select signals, and reference numerals 613 and 623. Denote bits that are not encrypted, and 614 and 624 denote bits that are encrypted. When the sample data 61 is input to the detection device 221, since the MSB is "1", the most significant bit 611 having the most significant "0" is detected. Next, a selection signal is output in which the lower bits, that is, the lower 11 bits, are higher than the most significant bit 611. Later, in the encryption device 223, a random number is added only to the bit whose selection signal is one. The bit to which the random number is added is represented by the bit 614 to be encrypted. The same process is performed also about the sample 62. The same applies to the sample data not shown in FIG.

As described above, by the randomization process performed by the combination of the detection device 221 and the encryption device 223, the position of the most significant bit of the sample data does not change. Since the most significant bit is dominant with respect to the level of the sample data, even if the reproduced audio signal is reproduced, it does not turn into an unusually large volume of voice, thereby realizing a Venus scramble that does not give an extreme discomfort to the listener. In addition, since the positions of the most significant bits remain unchanged by the processing, it is not necessary to transmit auxiliary data such as information of the position at which the processing is performed. This effect can be obtained even without the switch device 32 of the comparison device 222 and the encryption device 223.

5 is a diagram showing the processing of the comparison device 222 of the randomization device 22 of the scrambler 12 of the first embodiment. In Fig. 7, reference numeral 71 denotes a kinsoku code, 721 and 731 indicate sample data, 722 and 732 indicate selection signals, and 723 and 733 indicate a comparison position.

When the comparator 222 inputs the sample data 721 and the selection signal 722 corresponding thereto, the MSB of the sample data 721 and the kinsoku code 71 is compared with the bit where the selection signal is 0. . That is, in this case, a comparison is made with respect to the comparison positions 723 of the upper five bits. As a result, since it is a mismatch, 1 is output as a processing flag. In this case, in the encryption device 223, a random number is added to the lower 12 bits of the sample data 721.

When the comparison device 222 inputs the sample data 731 and the selection signal 732 corresponding to the sample data 731, the comparison data 731 and the kinsoku code 71 at the position where the selection signal is zero are compared. That is, in this case, a comparison is made with respect to the comparison position 733 of the upper 3 bits. As a result, 0 is output as the processing flag. In this case, the encryption device 223 does not add a random number to the sample data 721.

As described above, according to the processing performed by the combination of the comparison device 222 and the encryption device 223, no processing is performed on the sample data in which the bits of the comparison position coincide with the kinsoku code 71. Therefore, the kinsoku code 71 ) Does not become another code, or another code does not become a kinsoku code (71). For sample data in which the bits of the comparison position do not coincide with the kinsoku code 71, processing is performed on the bits other than the comparison position. Therefore, even after the processing, the sample data and the kinsoku code remain in different states, and therefore, the process is not a kinsoku code after the processing.

In addition, non-dynamic codes and codes having the same number of bits from the MSB side are codes at the end of the dynamic range, and the appearance frequency of such codes is very small in the characteristics of the digital audio signal. Therefore, the probability that the upper four bits of the sample data coincide with the upper four bits of the Ox8000 becomes small, and since most codes can be encrypted in practical use, the safety is not significantly impaired.

In addition, although the case where the kinsoku code is Ox8000 is shown here, it is not limited to this. When the kinsoku code is different from Ox8000, the comparator 222 is configured to compare the kinsoku code with sample data in a similar manner. As a result, kinsoku processing for any kinsoku code can be realized.

In addition, although the case where there is one kind of kinsoku code is shown here, it is not limited to this. When there are a plurality of kinsoku codes, the kinsoku codes of all of them are compared with the sample data. As a result of this comparison, if any one is matched, the processing flag is set to 0, and if it does not match at all, the processing flag is set to 1 and output. According to this, kinsoku processing for a plurality of kinsoku codes can be realized.

In this case, the processing target is an audio signal composed of a plurality of sample data, but the present invention is not limited thereto. Applicable to any digital data consisting of a plurality of codewords of the same length, the kinsoku process can be realized.

As described above, according to the randomization device 22, the scramble process can be realized so that the process will not become an extreme large volume after processing, it will have sufficient stability, and the kinsoku process for any kinsoku code can be performed.

In the scramble device 12 of the present embodiment, the inversion device 21 and the randomization device 22 are connected to perform the processing. As a result, the scrambler can be realized in which the kinsoku process can be performed with respect to any kinsoku code without the extreme loudness after the treatment, and the safety can be increased by the combination.

Next, the operation of the descrambler 16 of the present embodiment will be described with reference to the drawings. 4A is a configuration diagram of the descrambler 16.

In Fig. 4 (a), reference numeral 21 denotes an inverting device, reference numeral 23 denotes a related information divider, and reference numeral 42 denotes a random number decoding device. Here, the inverting device 21 and the related information splitting device 23 operate in the same manner as the device of the same name shown in FIG.

4 (b) shows the configuration of the random number decryption device 42, 221 is a detection device, 222 is a comparison device, and 423 is a encryption and decryption device. Here, the operation of the detection device 221 and the comparison device 222 performs the same operation as the device of the same name shown in FIG. The encryption / decryption apparatus 423 performs an inverse conversion operation of the encryption apparatus 223. The encryption / decryption apparatus 423 for the encryption apparatus 223 shown in FIG. 3 can be realized with the same configuration and operation as the encryption apparatus 223.

As indicated above, according to the descrambling device shown in FIG. 4, since the inverse conversion is performed at the same place where the scramble processing has been performed in the data scrambler 12, it is possible to restore correctly.

As indicated above, according to the present embodiment, when the scrambled voice information is reproduced, the extreme loudness is not achieved, and the scrambled voice information has sufficient concealment, and the banning process for any kinsoku code is possible. The scramble system can be realized.

In addition, in the first embodiment of the present invention, the scrambler 12 is configured to connect the random number device 22 to the rear end of the inverter 21, and the descrambler 16 has a random number decoder 42. Although the inverting apparatus 21 is connected to the rear end of (), it is not limited to this, You may connect each in reverse order, and the same effect is acquired. Moreover, it is good also as a structure which has only one, and the effect only of the apparatus can be acquired. In this case, the effect that the circuit can be simplified is obtained.

In addition, in the random number device 22 of the scrambler 12 and the descrambler 16 in the first embodiment of the present invention, the comparator 222 and the switch device 32 are provided. It is not limited to this. If there is no kinsoku cord, there is no problem even if the comparator 222 and the switch device 32 are not provided.

In addition, although the randomization apparatus 22 of the scrambler 12 and the descrambler 16 in 1st Example of this invention is comprised with the detection apparatus 221, it is limited to this. It is not. The detection device 221 may be eliminated by setting the selection signal to a fixed value or a value selected at the time of use. In this case, the effect of keeping the volume change before and after scramble constant, the effect of controlling the change, and the effect of simplifying the circuit can be obtained. It goes without saying that the kinsoku process can be realized in this case as well.

The comparison apparatus 222 according to the first embodiment of the present invention is configured to determine the position of the comparison based on the input selection signal. However, the most significant bit, such as the ox code, is placed in the upper 2 bits. If present, the present invention is not limited to this configuration, but may be configured to compare the upper two bits in a fixed manner. The reason is shown. As for the selection signals for the sample data in which the upper two bits match the kinsoku code, 14 bits are all one, and the comparison device 222 compares the upper two bits. It is apparent that sample data in which the upper two bits do not coincide with the kinsoku code may be inconsistent even if several bits are compared. Also, since the bits to be encrypted are only the lower 14 bits, this relationship is maintained even when decrypting. From the above result, a comparison of the upper two bits is sufficient. According to this, in addition to the same effect, the effect which can simplify a apparatus can be acquired.

In the random numbering device 22 of the present embodiment, although the bits lower than the most significant bit are all 1 and the other bits are 0, a configuration signal of 14 bits is used. However, the present invention is not limited thereto. no. Only the lower bits than the most significant bit may be randomized. Therefore, as the selection signal, any form, such as data having a lower level than all the most significant bits and all other bits being 0 and data indicating the position of the most significant bit, can be selected.

In addition, in the first embodiment of the present invention, a processing flag of 1 is used when the upper two bits and the sample at the position where the selection signal is 0 and the kinsoku code coincide with each other. However, the processing flag is not limited to this, and any processing flag may be any information indicating whether or not the bit at the position at which the selection signal does not encrypt is identical to the sample and the kinsoku code.

Note that the encryption device 223 according to the first embodiment of the present invention can take any configuration as long as the processing flag is 1 when the sample data of the position where the selection signal is 1 is randomized. For the sake of brevity, an embodiment of the encryption apparatus 223 having another configuration as shown in FIG. 3 is shown.

8A shows a block diagram of the encryption apparatus 223 to which the block encryption processing is applied. In Fig. 8 (a), reference numeral 81 denotes a separation device, 82 a block encryption device, and 83 a synthesis device. The separating device 81 inputs an audio signal, a processing flag, and a selection signal, outputs data at a position where the selection signal of the sample data having a corresponding processing flag of 1 is 1 as processing data, and stores other data. Output as processing data. Next, the block encryption apparatus encrypts and outputs the process data. The synthesizing apparatus 83 synthesizes the output of the block cipher 82 and the unprocessed data. At this time, the synthesizing apparatus 83 inputs a processing flag and a selection signal, and performs inverse conversion of the separating apparatus 81.

In addition, a block diagram of the encryption / decryption apparatus 423 to which the block encryption processing is applied is shown in FIG. Numeral 81 is a separating device, numeral 84 is a block cipher decoding device, numeral 83 is a synthesizing device. Here, the operations of the separating device 81 and the combining device 83 are the same as those of the description of the encryption device of FIG. The block encryption / decryption apparatus 84 performs inverse transformation of the block encryption apparatus 82.

The same effect can be acquired also by the above structure.

The scrambler 12 and the descrambler 16 in the first embodiment of the present invention are constituted by processing 16-bit sample data, but the present invention is not limited thereto. When performing processing for n bits of sample data, the processing performed in units of 16 bits may be extended to n bits.

Further, in the scramble system of the first embodiment of the present invention, the digital audio signal composed of a plurality of sample data is subjected to processing, but is not limited thereto. Codes of the same bit length may be subjected to processing of arbitrary digital data collected in plural numbers. In this case, the kinsoku process can be realized.

[MPEG]

A second embodiment of the present invention will be described below with reference to the drawings. 9 shows the configuration of the voice scramble system according to the second embodiment of the present invention. In Fig. 9, reference numeral 91 denotes a digital voice generator, 92 denotes an MPEG audio encoder, 93 denotes a scrambler, 94 denotes a transmission device, 95 denotes a transmission path, and 96 denotes a reception channel. Apparatus 97 is a descrambler apparatus 98 is an MPEG audio encoding apparatus 99 is a digital speech processing apparatus.

In the scramble system of this embodiment configured as described above, the operation will be described below. For the digital voice generator 91, the transmission path 95, and the digital voice processor 99, the digital voice generator 11, the transmission path 14, and the digital voice processor of the scramble system of the first embodiment are respectively. Since operation similar to (17) is performed, detailed description will not be given here.

The MPEG audio encoding device 92 encodes the digital audio signal output from the digital voice generation device 91 for data compression, and outputs the resulting MPEG audio signal. The operation of the MPEG audio and MPEG audio encoding apparatus 92 will be described later. Next, the scrambler 93 scrambles the MPEG voice output from the MPEG voice coder 92. The operation of this scrambler 93 will be described later in detail. Next, the transmitter 94 transmits the output of the scrambler 93 via the transmission path 95 and receives it from the receiver 96. Next, the descrambler 97 descrambles the MPEG audio signal. This descrambling device 97 is a device for performing inverse conversion of the scrambler 93, and the operation thereof will be described later in detail. Next, the MPEG audio decoding device 98 decodes the MPEG audio signal and outputs the resulting digital audio signal.

First, MPEG audio will be described. Moving Picture Exper Group (MPEG) is a collective name of ISO-IEC / JTC1 / SC2 / WG11, which is a group that performs international standard work of digital video and audio high efficiency encoding method. The MPEG audio signal represents data that has been encoded by this method. There are three methods of Layer I, Layer II, and Layer III according to the difference of the methods. The details of MPEG audio are indicated in (MPEG CD 11172-3 CODING OF MOVING PICTURES AND ASSOCIATED AUDIO FOR DIGITAL STORAGE MEDIA AT UP TO ABOUT 1.5 MBIT / s, part 3 AUDIO).

The operation of the MPEG audio encoding apparatus for making Layer I MPEG audio is briefly shown below.

First, frame data consisting of a plurality of sample data is subjected to frequency conversion and divided into a plurality of subbands. Next, the maximum amplitude in each western band is determined, and the sample data of each subband is normalized to the maximum amplitude. Next, the data of each subband after normalization is quantized to be quantized data. At this time, the number of quantization bits in quantization is determined for each subband according to the characteristics of the voice sample, and quantization is performed according to the value. Finally, bit allocation information indicating the number of quantization bits of each subband, amplitude information indicating the maximum amplitude of each subband, and quantization data of each subband are synthesized into an audio signal. The audio signal also includes header information indicating a method of encoding or the like.

In actual layer I audio encoding of MPEG audio, each frame is divided into 32 subbands with 384 samples (for 8 msec in the case of a sample frequency of 44.1 KHz) as one frame.

Thus, each subband consists of 12 samples. Thereafter, as described above, bit allocation, normalization, and quantization processing are performed, and a bitstream is generated.

The format of the bitstream of one frame of the layer I of the MPEG-1 standard audio thus produced is shown in Table 1.

In Table 1, header corresponds to header information, allocation [sb] corresponds to bit allocation information, scale factor [sb] corresponds to amplitude information, and sample [sb, s] corresponds to quantized data. Here, sb is a subband index, is numbered for each subband, and used to indicate which subband each data corresponds to. In addition, s is a sample index, which is numbered for each sample, and is used to indicate which sample each data corresponds to. 32max means that no transmission is made when bit allocation information (allocation [sb]) is zero. Error_check is information for checking for errors, and ancillary_data is auxiliary data.

10 is a block diagram of the audio scramble apparatus according to the second embodiment of the present invention. In Fig. 10, reference numeral 101 denotes a dividing apparatus, 102 a scramble processing apparatus, and 103 a synthesizing apparatus.

The operation will be described below.

First, the division apparatus 101 inputs an MPEG audio signal of Layer 1, obtains the position of the quantized data (sample [sb, s]) from the data of heaer and allocation [sb], and obtains the quantized data (sample [sb, s). ]) And data other than quantization data (header, error_chcek, allocation [sb], scalefactor [sb], ancillary-data), and output each. As a method of obtaining the position of the quantized data, first, the header confirms that the MPEG audio signal is Layer I of MPEGI, and detects the presence or absence of error_check. Next, the data amounts of scalefactor [sb] and sample [sb, s] are obtained by allcation [sb]. As a result, the position of the quantized data is obtained. The method for obtaining the position of the quantized data is not limited to this and can be obtained by any method. For example, if the presence of error_check is fixed, there is no need to use a header.

Next, the scramble processing apparatus 102 inputs quantization data and scramble related information, and performs scramble processing on the quantized data using the scramble related information. Finally, the synthesizing apparatus 93 inputs quantization data output from the scramble processing apparatus 102 and data other than the quantization data output from the dividing apparatus 101, synthesizes them so that the quantization data is in the original position. It generates and outputs MPEG audio signal of Layer I.

10 is a configuration diagram of an audio descrambler. In Fig. 10, reference numeral 101 denotes a decomposing device, 112 descrambles processing device, and 93 a synthesizing device. The operation will be described below.

The audio descrambler uses the MPEG audio signal of Layer I after the scramble process is performed by the scrambler shown in FIG. The dividing apparatus 101 and the synthesizing apparatus 93 operate exactly the same as the apparatus of the same name in the scrambler shown in FIG. 9, and therefore not particularly described herein.

Next, the descramble processing apparatus 112 inputs the quantized data and the scramble related information, and descrambles the quantized data using the scramble related information. At this time, the scramble related information input to the descrambling processing unit 112 is the same as the scramble related information used when the quantized data to be scrambled is subjected to the descrambling processing. Inverse conversion of the scramble processing in the scramble processing apparatus 102.

The method of the scramble processing of the scramble processing apparatus 102 of the voice scramble system in the second embodiment and the method of the descrambling processing of the descrambling apparatus 112 which is the voice descrambling apparatus to be inversely converted are specifically indicated. However, a block encryption method using scramble related information as key data or a scramble related information as a random number, a method of exclusive logical sum of the random number, scrambled by an arbitrary scramble process, and a descramble process which is an inverse transformation of the scramble process. This may be descrambled, and the same effect can be obtained by either method.

In the scrambler 93 and the descrambler 97, the division device 101 and the synthesis device 103 are used to scramble only quantized data, but the configuration is not limited to this configuration. The scrambler can take any configuration as long as it scrambles only the quantized data and does not scramble other data. For example, the present invention can be realized by a combination of a detection device that detects a position of quantized data and outputs detection data indicating the position, and an encryption device or encryption / decryption device that performs processing only at the position indicated by the detection data. have.

As described above, according to the second embodiment, only the quantized data samples [sb and s] are scrambled, and the amplitude information scalefactor does not change due to scramble. As a result, the quantized data of each subband is randomized. However, since the maximum amplitude at the time of decoding is preserved, the data of each subband does not grow strangely, and no abnormal frequency component occurs. In addition, even when viewed as a whole, it is not unusually large in amplitude, and voice scrambles that do not give extreme discomfort to the listener can be realized.

In addition, the descrambler 97 performs descrambling processing that is inversely transformed on the scrambled sample. Thereby, the MPEG sound data scrambled by the scrambler 93 can be correctly restored.

In addition, in the audio scramble system of the second embodiment, a single channel MPEG voice having the configuration shown in Table 1 is subjected to processing. However, the present invention is not limited to this and can be realized by repeatedly applying the processing to data of each channel even for MPEG audio of a plurality of channels.

In the audio scramble system of the second embodiment, MPEG audio of Layer I shown in Table 1 is subjected to processing. However, the present invention is not limited to this, but includes header information indicating a compression method and a plurality of subband data, such as a bit stream of an MPEG voice of Layer II, and the individual subband data includes bit allocation information and amplitude. Any audio signal having quantized data quantized to the number of bits displayed in the bit allocation information after being normalized by the information and the amplitude information may be subjected to processing. In this case, the same effect can be obtained as long as the dividing device is divided into quantized data and other data.

Here, the audio encoding of the MPEG audio of Layer II is performed differently to improve the coding efficiency than the audio encoding of the Layer I, and generates non-streams of different formats.

However, the bitstream has header information indicating a method of compression and a plurality of subband data, and each subband data is displayed in the bit allocation information after being normalized by bit allocation information, amplitude information and the amplitude information. It is the same as Layer I in that it has quantized data quantized by the number of bits.

Also, a quantization normalized by amplitude information and the amplitude information, such as an audio signal having no header information and a fixed encoding method, a speech signal having no fixed header information and bit allocation information, and a fixed position of quantized data in a non-stream. Any audio signal having data may be the object of processing. In this case, the same effect can be obtained as long as the dividing device is divided into quantized data and other data.

Further, in the voice scramble system of the second embodiment, the dividing apparatus 101 is divided into all the quantization data and the data other than the quantization data, and the scramble processing apparatus 102 and the descrambling apparatus 112 process all the quantization data. We do with configuration to say. However, the division apparatus 101 may be configured to divide the quantization data of the specific subband data and other data, or the scramble processing apparatus 102 and the descramble processing apparatus 112 process only a part of the quantization data. It is good also as a structure to make. In particular, if only the quantized data of subband data other than at least a high frequency band is used, the scramble processing apparatus 102 can randomize at least an intermediate frequency that dominates most of the features of speech. Therefore, concealment is not largely impaired. As a result, a scrambler can be configured to further reduce the discomfort caused by the scrambled voice to the listener because no noise is generated in the high frequency band. The effect is possible.

The subband data to be processed may be determined by a control signal input from the outside. In this case, it is possible to obtain the effect that the degree of discomfort and concealment degree to the listener can be controlled by the control signal.

Claims (12)

A scramble system for scrambling and descrambling a digital audio signal composed of a plurality of sample data, the scramble system includes a scrambler and a descrambler, wherein the scrambler inputs the sample data and If the MSB is "1", the most significant bit that becomes "0" among the bits other than the MSB is detected as the most significant bit. If the MSB of the sample data is "0", the "1" among the bits other than the MSB is detected. By detecting the most significant bit as the most significant bit, all or part of the bit positions lower than the detected most significant bit are designated as encrypted data positions, and other data positions are displayed as non-encrypted data positions. The position of scrambled is determined according to the data of the sample data, and the position of scrambled is determined. Display includes a detecting device for outputting the detection data; And an encryption device for encrypting the sample data and the detection data output from the detection device as inputs, and encrypting the position of the encrypted data represented by the detection data of the sample data, that is, the scrambled location. The descramble device includes: the detection device; An encryption which is an inverse transformation of the encryption processing apparatus with respect to the position of the encrypted data displayed by the sample data and the detection data output from the detection device as input, that is, the scrambled position A scramble system, characterized by comprising an encryption and decryption apparatus for performing a decryption process. A scramble system for scrambling and descrambling a digital audio signal composed of a plurality of sample data, the scramble system includes a scrambler and a descrambler, wherein the scrambler inputs the sample data and A detection device which compares whether or not the data of the comparison position of the sample data and the data of the comparison position of the kinsoku code are identical, with one or more bits as a comparison position, and outputs the comparison result as detection data; And an encryption device which performs processing on data other than the comparison position of the sample data when the detection data indicates an inconsistency, wherein the descramble device comprises: the detection device; And an encryption / decryption apparatus for performing encryption / decryption processing on data other than the comparison position of the sample data when the detected data indicates a mismatch. The detection device according to claim 1, wherein the detection device is composed of a first detection device and a second detection device, and the first detection device is configured to be "0" among bits other than the MSB when the MSB of the sample data is "1". The uppermost bit is detected as the most significant bit, and when the MSB of the sample data is "0", the most significant bit that becomes "1" among the bits other than the MSB is detected as the most significant bit, and the detected most significant The first detection data outputting all or part of the bit position lower than the bit as the encrypted data position, and displaying other data positions as the non-encrypted data position, and the second detection device outputs one of the sample data. A bit or more is used as a comparison position, the data of the comparison position of the sample data and the data of the comparison position of the kinsoku code are compared or not, and the comparison result is used as the second detection data. And the first detection data and the second detection data output from the sample data and the detection device are inputted, and the encryption device is displayed by the first detection data of the sample data. When at least the second detection data indicates a match at the time of encrypting the encrypted data position, the sample data is not encrypted. The encryption / decryption apparatus is the sample data and the detection apparatus. At least the second detection when encrypting and decrypting the encrypted data position represented by the first detection data and the second detection data outputted from the first detection data of the sample data. If the data indicates a match, the sample data is not encrypted and decrypted. Scrambled system. In a scrambler for scrambled a digital audio signal composed of a plurality of sample data, when the sample data is input and the MSB of the sample data is "1", the highest bit that becomes "0" among the bits other than the MSB. Is detected as the most significant bit, and when the MSB of the sample data is "0", the most significant bit that becomes "1" among the bits other than the MSB is detected as the most significant bit, and is lower than the detected most significant bit. All or part of the bit positions of " encoded data position " A detection device for outputting the sample data and the detection data output from the detection device. Power to, and the position of the encryption data represented by the detected data of the sample data, that is, with respect to the scramble position, comprising the encryption apparatus for encrypting a scramble apparatus. A scrambler for scrambled a digital audio signal composed of a plurality of sample data, comprising: inputting the sample data, and setting one or more bits of the sample data as a comparison position, the data of the comparison position of the sample data and the kinsoku code A detection device that compares whether or not the data of the comparison positions match and outputs the result of the comparison as detection data, and performs processing on data other than the comparison position of the sample data when the detection data indicates inconsistency. Scrambled device characterized in that it comprises an encryption device. The detection device according to claim 4, wherein the detection device comprises a first detection device and a second detection device, and the first detection device is a head that becomes "0" among bits other than the MSB when the MSB of the sample data is "1". The uppermost bit is detected as the most significant bit, and when the MSB of the sample data is "0", the most significant bit that becomes "1" among the bits other than the MSB is detected as the most significant bit, and the detected most significant The first detection data outputting all or part of the bit position lower than the bit as the encrypted data position, and displaying other data positions as the non-encrypted data position, and the second detection device outputs one of the sample data. A bit or more is used as a comparison position, the data of the comparison position of the sample data and the data of the comparison position of the kinsoku code are compared or not, and the comparison result is used as the second detection data. And the first detection data and the second detection data output from the sample data and the detection device are inputted, and the encryption device is displayed by the first detection data of the sample data. And at least the second detection data, when encrypting the encrypted data position, does not perform encryption processing on the sample data. A descrambler for descrambling a digital audio signal consisting of sample data subjected to a plurality of encryption processes, wherein the sample data is input, and when the MSB of the sample data is " 1 ", " 0 " "Is detected as the most significant bit. If the MSB of the sample data is" 0 ", the most significant bit that becomes" 1 "among the bits other than the MSB is detected as the most significant bit, and is detected. All or part of a bit position lower than the most significant bit is designated as an encrypted data position, and other data positions are displayed as non-encrypted data positions, whereby a scrambled position is determined according to the sample data, and the scrambled A detection device for outputting detection data indicating a position, and exiting from the sample data and the detection device And an encryption / decryption apparatus configured to perform an encryption / decryption process, which is an inverse conversion of the encryption process, on the encrypted data position indicated by the detected data of the sample data, that is, the scrambled position. Descrambling device characterized in that. A descrambling device for descrambling a digital audio signal consisting of sample data subjected to a plurality of encryption processes, the descrambling apparatus inputting the sample data and comparing the sample data with one or more bits of the sample data as a comparison position. A detection device which compares whether or not the data of the position and the data of the comparison position of the kinsoku code match and outputs the result of the comparison as the detection data, and the comparison of the sample data when the detection data indicates inconsistency. A descrambler, comprising: an encryption / decryption apparatus for performing encryption / decryption processing on data other than the position. 8. The detection device according to claim 7, wherein the detection device is composed of a first detection device and a second detection device, and the first detection device is configured to be "0" among bits other than the MSB when the MSB of the sample data is "1". The uppermost bit is detected as the most significant bit, and when the MSB of the sample data is "0", the most significant bit that becomes "1" among the bits other than the MSB is detected as the most significant bit, and the detected most significant The first detection data outputting all or part of the bit position lower than the bit as the encrypted data position, and displaying other data positions as the non-encrypted data position, and the second detection device outputs one of the sample data. A bit or more is used as a comparison position, the data of the comparison position of the sample data and the data of the comparison position of the kinsoku code are compared or not, and the comparison result is used as the second detection data. And the first detection data and the second detection data output from the sample data and the detection device are inputted, and the encryption device is displayed by the first detection data of the sample data. And at least the second detection data indicates a coincidence when encrypting and decrypting the encrypted data position, wherein the sample data is not encrypted. A digital scramble system comprising: a plurality of subband data, each of the subband data being scrambled and descrambled with a digital audio code having at least amplitude information and quantized data quantized after normalizing by the amplitude information. The individual subband data of the speech code is characterized by having quantization data quantized to the number of bits displayed in the bit allocation information after being normalized by bit allocation information, amplitude information and the amplitude information. And a scrambler, a scrambler, wherein the scrambler inputs the digital voice code, detects a position of the quantized data of all or part of the subband data from the bit allocation information of the digital voice code, And encrypting the quantized data of the detected position And a decode device for encoding the amplitude information. The descrambler inputs the digital voice code outputted from the scrambler, from the bit allocation information of the digital voice code. The position of the quantized data of all or part of the subband data is detected, the encryption and decryption processing is performed on the quantized data of the detected position, and the encryption and decryption processing is not performed on the amplitude information. The scramble system, characterized in that the reverse conversion of the encryption process in the encryption device. A scrambler having a plurality of subband data, wherein each of the subband data is scrambled with a digital speech code having at least quantized data after being normalized by amplitude information and the amplitude information. The subband data has quantization data quantized by the number of bits displayed in the bit allocation information after being normalized by the bit allocation information, the amplitude information, and the amplitude information, and inputs the digital speech code. The position of the quantized data of all or part of the subband data is detected from the bit allocation information of the digital voice code, and the encryption process is performed on the quantized data of the detected position, and the encryption process is not performed on the amplitude information. Characterized in that it is configured as an encryption device Scramble apparatus. Each subband data having a plurality of subband data, each of which is a digital voice code having at least quantized data after being normalized by amplitude information and the amplitude information, and descrambles the digital voice code subjected to scramble processing. In the descramble device, each of the subband data of the digital speech code has quantization data quantized by the number of bits displayed in the bit allocation information after being normalized by bit allocation information, amplitude information, and the amplitude information. Inputting the digital speech code, detecting the position of the quantized data of all or part of the subband data from the bit allocation information of the digital speech code, and encrypting the quantized data of the detected position. Decryption processing is performed, and the amplitude information is encrypted Without performing the screen processing, the encryption decoding process descrambling device characterized in that the inverse of the encryption process.