JPH1022997A - Method and device for transmitting data - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and device for transmitting data capable of cipher communication without using a line of a large capacity. SOLUTION: From a transmission part 15, data the ciphering unit of which is made 64 bits is sent to a reception part 2 by each 8 bits in an order starting from a leading block by adding additional data to every 512 bits. The reception part 22 receives data sent by each 8 bits, reproduces it by each bits and a the time of not detecting additional data showing a data division at the point of the time of reproducing 512 bits, abolishes all the pieces of data until additional data is detected next.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a data transmission method and a data transmission device.

[0002]

2. Description of the Related Art When performing voice communication or image communication using digital signals, even if some data is inverted or lost due to noise on a transmission line, it does not affect data after the error occurs. However, when transmitting encrypted data, there is a drawback in that data after the location where an error occurs is affected. That is, in general, encryption is performed not in units of about 8 bits but in units of 64 bits or 128 bits in order to increase encryption strength, and transmission is generally performed in units of 8 bits. For example, when data loss occurs due to the influence of noise or the like, data is lost every 8 bits.

[0003] For example, as shown in FIG.
Eight bits (8 bytes) of encrypted data (512 bytes)
Bit) is transmitted one byte at a time, and if the first one byte of data is lost, only 504 bits of data reach the receiving side. The receiving side attempts to decrypt with 64 bits from the beginning, but since the first byte is missing, it does not match the data at the time of encryption, and the decrypted result becomes a complete random number in cryptography. turn into. Further, both the 64-bit data that arrives next and the data after that will be random numbers. For this reason, conventionally, as shown in FIG. 6, additional data for error detection is added to each of the encrypted 64-bit data, and information loss is performed on the receiving side based on the additional data. If it is determined that information is missing, only the missing data is discarded so that the subsequent data can be correctly decoded.

[0004]

However, in such a conventional data transmission method, transmission is performed by adding additional data for error detection to each of the data encrypted on the transmission side. There has been a problem that the amount of data has increased and a large-capacity line must be used.

Accordingly, an object of the present invention is to provide a data transmission method and a data transmission apparatus capable of performing encrypted communication without using a large-capacity line.

[0006]

In order to achieve the above object, the data transmission method according to the first aspect of the present invention is characterized in that, on the transmitting side, the unit of encryption is n (n: positive integer) bits. The added data is added to each of the plurality of pieces of data, and additional data indicating a data delimiter is added.
If data transmitted from the transmitting side is received and the additional data cannot be detected at that time, all data during that time is discarded until the next additional data is detected.

According to this method, data sent by i bits is received, reproduced by n bits, and
If additional data indicating a data delimiter cannot be detected at the time of block reproduction, all data until the next additional data can be detected is discarded. That is, if there is a data loss in one block, a part of the following data is packed in the missing part, and the state becomes the same until the additional data located at the end of the block is obtained. Makes it impossible to detect additional data. Therefore, all data during that time is discarded until additional data is detected next.

[0008] Note that noise occurs in data in which data is missing or the like, and the data following the data has no meaning because the content has changed. However, this phenomenon occurs only in the block to which the data belongs. Since all the data until the additional data is detected is discarded, the period during which the problem occurs is short, so that there is no major problem in voice transmission such as telephone. Therefore,
Since additional data is added only to a block in which a plurality of pieces of encrypted n-bit data are grouped together, a large-capacity line is used as in the related art in which additional data is added for each n-bit data. And it is possible to perform encrypted communication.

According to a second aspect of the present invention, there is provided a data transmission apparatus comprising: an encryption unit for generating data in which an encryption unit is n (n: positive integer) bits; and a plurality of data generated by the encryption unit. A data adding unit that adds additional data indicating a data delimiter for each unit, a transmitting unit that outputs data output from the data adding unit to a transmission path by i (i: positive integer, i <n) bits, Receiving means for receiving the data transmitted from the transmitting means via the transmission path, and if the additional data cannot be detected from the received data output from the receiving means, a period until the next additional data is detected; And additional data detecting means for discarding all the data, and decoding means for decoding data not discarded by the additional data detecting means.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. (I) First Embodiment FIG. 1 is a block diagram showing a configuration of a data transmission apparatus according to a first embodiment of the present invention. In the figure, a data transmission device 1 includes a microphone 10, an A / D conversion circuit 11,
Encryption circuit 12, data addition circuit 13, and transmission circuit 14
And a receiving unit 22 including a receiving circuit 16, an additional data detecting circuit 17, a decoding circuit 18, a D / A converting circuit 19, an amplifying circuit 20, and a speaker 21. The transmitting unit 15 and the receiving unit 22 are connected via a transmission path 25. When a two-way communication is performed like a telephone, it is assumed that both the transmission unit 15 and the reception unit 22 are provided.

The A / D conversion circuit 11 digitizes the sound input from the microphone 10 and the encryption circuit 12
The digital signal from the / D conversion circuit 11 is encrypted into 64-bit data. The data adding circuit 13 adds the additional data indicating the data delimiter to the data of 64 bits encrypted by the encryption circuit 12 every 512 bits (one block). The transmission circuit 14 is a data addition circuit 13
Are output to the transmission line 25 in 8-bit units. The receiving circuit 16 receives the data transmitted via the transmission path 25 and supplies the data to the additional data detecting circuit 17.

The additional data detecting circuit 17 supplies the received data to the decoding circuit 18 as it is, aligns the received data 64 bits at a time, and checks whether the last additional data in one block has the initial value (81H). If it is determined that the value is not the initial value, that is, if the additional data cannot be detected, all the data is discarded until the next additional data can be detected. The decoding circuit 18 decodes the data from the additional data detection circuit 17, and the D / A conversion circuit 19 converts the decoded data into an analog signal. The amplification circuit 20 amplifies the analog signal from the D / A conversion circuit 19 and supplies the analog signal to the speaker 21.

FIG. 2 is a diagram showing an outline of a data processing process when voice is sampled at 8 kHz and 8 bits (sound quality slightly better than that of a normal telephone). In this figure, when the 8-bit data output from the A / D conversion circuit 11 every 125 microseconds becomes 64 bits, the data is encrypted to generate 64-bit data. Further, when the 64-bit data becomes 512 bits, additional data is added to form one block of data. On the other hand, the encrypted 64-bit data is transmitted 8 bits at a time from the beginning, received by the receiving unit 22, and reproduced 64 bits at a time.

As shown in the figure, if up to sixty-four 64-bit data are normally reproduced, and eight-bit data is lost at the seventh bit to become 56 bits, decoding becomes impossible, and noise is reduced. Appears. In this case, the additional data detection circuit 17 performs a process of packing the 8-bit data transmitted next to the 56-bit data into the missing portion of the 56-bit data. As a result, the next data becomes 56 bits. In this case, 8-bit data of the value of the additional data is brought. For this reason, the value of the additional data changes from the initial value, and the additional data detection circuit 17 cannot detect the additional data. Therefore, the additional data detection circuit 17 discards all data during the period until the next additional data is obtained.

In the case where this voice is sampled at 8 kHz and 8 bits and additional data is added every 64 bits or 512 bits as a unit of encryption, a line having a capacity of 65000 bits / second is sufficient, but it has been conventionally performed. Method (64
In the case of adding 16-bit additional data to bits), a line having a capacity of 80000 bits / second is required.
By the way, if there is data matching the additional data in the data output from the A / D conversion circuit 11 (assuming that the encryption result is a perfect random number, the matching probability is 1).
/ 256), the data is erroneously recognized as additional data, and does not become a data delimiter there,
It becomes noise. However, in this case, since it is not possible to detect additional data that should appear later, it can be detected that this data is not additional data. Therefore, even if data that coincides with the additional data exists in the data, there is no permanent recovery of the data break.

As described above, in the first embodiment, data transmitted by 8 bits is received, reproduced by 64 bits, and additional data indicating a data break cannot be detected when 512 bits are reproduced. In this case, all data is discarded until additional data can be detected next.
Therefore, since the additional data is added every 64 bits and every 512 bits of the encryption unit, the encrypted communication can be performed without using a large-capacity line as in the prior art in which the additional data is added every 64 bits. Thus, a remarkable effect can be obtained in real-time communication in which a retransmission request cannot be made even if a transmission error occurs and the transmission capacity is restricted.

(II) Embodiment 2 FIG. 3 shows a case where voice is sampled at 5.6 kHz and 4 bits (sound quality slightly worse than that of a normal telephone), and an encryption unit is added every 64 bits and every 512 bits. It is a figure which shows the outline of the data processing process at the time of adding data. In the second embodiment, a line having a capacity of 22750 bits / sec is sufficient, but the method conventionally used (adding 16-bit additional data to 64 bits) requires 28000 bits.
A line with a capacity of bits / second is required. Since the effective line capacity of the 28800 bits / second modem currently used for the analog line is only 23040 bits / second, it is impossible in this case to perform encrypted communication with the conventional technology.

(III) Embodiment 3 FIG. 4 shows a case where voice is sampled at 11 kHz and 4 bits (sound quality better than that of a normal telephone), and additional data is added in units of 64 bits and 512 bits for encryption. FIG. 3 is a diagram showing an outline of a data processing process. In the second embodiment, a line having a capacity of 44687.5 bits / second is sufficient.
Conventional method (16 bits for 64 bits)
In this case, a line having a capacity of 55000 bits / second is required. Since the effective line capacity of the asynchronous ISDN terminal adapter of 57600 bits / sec is only 46080 bits / sec, in this case, it is impossible to perform the encrypted communication by the conventional technique.

In each of the above embodiments, the present invention is applied to the transmission of audio. However, it is needless to say that the present invention can be applied to the transmission of a video signal from a television or the like. In each of the above embodiments, the unit of encryption is 64 bits, and the unit of encryption is 512 bits.
Although the additional data is added for each bit, the present invention is not limited to these values. In short, any value may be selected unless additional data is added for each encryption unit. The same applies to the method of sampling audio.

[0020]

As described above, according to the data transmission method according to the first aspect of the present invention, on the transmitting side, the data having the encryption unit of n bits is added to indicate the data division for each of a plurality of data. The data is added, and the data is sent to the receiving side in i-bit units in order from the first block. The receiving side receives the data sent in i-bit units and reproduces the data in n-bit units. If the additional data indicating the data delimiter cannot be detected, all data until the next additional data can be detected is discarded.
It is possible to perform encrypted communication without using a large-capacity line as in the conventional technology in which additional data is added for each bit of data. A remarkable effect can be obtained in real-time communication in which there is a restriction.

According to the data transmission apparatus of the second aspect of the present invention, data having an encryption unit of n bits is added with additional data indicating a data delimiter for each of a plurality of pieces of data, and i In addition to transmitting the data bit by bit, receiving the data transmitted i bits at a time, reproducing the data n bits at a time, and when the additional data indicating the data delimiter cannot be detected when one block is reproduced, Since all data is discarded until additional data can be detected, encrypted communication can be performed without using a large-capacity line as in the related art in which additional data is added for each n-bit data. It is possible to obtain a remarkable effect when used for real-time communication in which retransmission request is impossible even if a transmission error occurs and transmission capacity is limited. That.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a data transmission device according to a first embodiment of the present invention.

FIG. 2 is a diagram schematically illustrating a data processing process according to the first embodiment.

FIG. 3 is a diagram schematically illustrating a data processing process of a data transmission device according to a second embodiment of the present invention.

FIG. 4 is a diagram schematically illustrating a data processing process of a data transmission device according to a third embodiment of the present invention.

FIG. 5 is a diagram schematically illustrating a data processing process according to a conventional data transmission method.

FIG. 6 is a diagram schematically illustrating a data processing process according to a conventional data transmission method.

[Explanation of symbols]

 Reference Signs List 12 encryption circuit (encryption means) 13 data addition circuit (data addition means) 14 transmission circuit (transmission means) 16 reception circuit (reception means) 17 additional data detection circuit (additional data detection means) 18 decoding circuit (decryption) Means) 25 Transmission line

Claims (2)

[Claims] On the transmitting side, additional data indicating a data delimiter is added for each of a plurality of data in which the unit of encryption is n (n: positive integer) bits, and i (i : Positive integer, i <n) bits are sent to the receiving side, and the receiving side receives the data sent from the transmitting side. If the additional data cannot be detected at this time, the next additional data is detected. A data transmission method characterized by discarding all data during that time. 2. An encryption means for generating data in which the unit of encryption is n (n: positive integer) bits, and additional data indicating a data division for each of a plurality of data generated by the encryption means. A transmitting means for outputting data output from the data adding means to the transmission path by i (i: positive integer, i <n) bits at a time; and a transmitting means via the transmission path. Receiving means for receiving the transmitted data; and additional data detecting means for, when the additional data cannot be detected from the received data outputted from the receiving means, discarding all data during the detection until the next additional data is detected. And a decoding means for decoding data not discarded by the additional data detection means.