JP2000285593A - System and method for data transmission, data transmitter and data receiver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To safely certify a data transmitter without putting clocks in equipment and recording sequence numbers for every communication party while constituting a data transmission system which transmits data from a data transmitter to a data receiver. SOLUTION: In the data transmitting method, a CPU 12 converts transmission data into first certifying information by a first conversion function at a data transmitter 10 side, the first certifying information is transmitted from an output interface 16 with transmission data through a transmission path 30. At a data receiver 20 side, the first certifying information transmitted with the transmission data is received through an interface 24, the received transmission data are converted in a CPU 22 to second certifying information by the first conversion function that is same as the transmitter side 10. Then, discrimination is made to determine whether the second certifying information and the received first certifying information are equal or not.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data transmission system for transmitting data in one direction from a data transmission device to a data reception device, a data transmission method, a data transmission device, and a data reception device.

[0002]

2. Description of the Related Art In recent years, devices for transmitting and recording digital data such as music information and video information at home have become widespread. Since these devices can record data with high quality, it is necessary to prevent unauthorized copying of copyrighted data.

For example, a key indicating whether or not movie information is permitted to be recorded in a magneto-optical disk device is stored, and the magneto-optical disk device is used as a legitimate device, that is, a copyright It is performed to authenticate whether or not the device is licensed by the right holder, and to permit recording of movie information only to a magneto-optical disk device that is authenticated as a legitimate device. In such a case, a device that transmits movie information (hereinafter, such a device is referred to as a source) and a device that receives the transmission (hereinafter, such a device is referred to as a sink) In between, it is necessary to authenticate whether or not the other device is an appropriate device.

[0004] For the purpose of copyright protection in such a system, various authentication methods have been proposed. An encryption algorithm is often used as an authentication protocol used for these authentication methods.

As an authentication method in a data transmission system for transmitting data in one direction from a data transmission device to a data reception device, one of ISO / IEC 9798-2 and 9798-4 is used.
Passauthentication is widely known.

[0006] One pass authenticatio of ISO / IEC 9798-2
In n, the data transmission device and the data reception device have a conversion function e_k_12 () and its inverse conversion function d_k_12 () in order for the data reception device to confirm the validity of the data transmission device. Then, the data transmitting device generates Token12 represented by the following equation using the conversion function e_k_12 (), and Token12 = e_k_12 (T-1) or Token12 = e_k_12 (N-1). Send to

Here, T-1 is a value generated by the data transmitting apparatus and changes with time, and N-1 is a value generated by the data transmitting apparatus between the data transmitting apparatus and the data receiving apparatus. It is a shared sequence number.

[0008] Then, the data receiving device that has received the Token12 performs an inverse transform of e_k_12 (T-1) or d_k_12 (N-1) by its own inverse transform function d_k_12 (), and the result is valid. Confirm that it becomes T-1 or N-1. When this confirmation is made, the data receiving device recognizes the validity of the data transmitting device and performs processing such as recording data.

[0009] One pass authent of ISO / IEC 9798-4
In ication, the data transmitting device and the data receiving device share a conversion function f_k_12 () so that the data receiving device checks the validity of the data transmitting device. Then, the data transmitting apparatus uses the conversion function f_k_12 () to calculate Tok expressed by the following equation.
En12 is generated, and Token12 = T-1 || f_k_12 (T-1) or Token12 = N-1 || f_k_12 (N-1) The generated Token12 is transmitted to the data receiving device.

Here, T-1 is a time-varying value generated by the data transmitting device, and N-1 is a value generated by the data transmitting device between the data transmitting device and the data receiving device. It is a shared sequence number.
As the conversion function f_k_12 (), for example, a keyed hash function can be used. || indicates that values are concatenated.

[0011] Then, the data receiving apparatus that has received the Token12 uses the conversion function f_k_12 () that has the received T-1 or N-1 and uses the conversion function f_k_12 (T-1) or f_k_12 (N- 1)
Is calculated independently, and it is confirmed that it is equal to the one transmitted from the data transmission device. When this confirmation is made, the data receiving device recognizes the validity of the data transmitting device and performs processing such as recording data.

[0012]

[Problems to be solved by the invention] By the way, ISO / IEC 97
In the one-pass authentication of 98-2 and 9798-4, in order to perform authentication safely, a value that changes according to time or a sequence number shared between two devices is used.

However, the value T-
To use 1, normally the device must have a clock, and to use the sequence number N-1, the device must store it for each connection partner. Therefore, no matter which method is used, a complicated system configuration is required to perform secure authentication.

Accordingly, an object of the present invention is to provide a data transmission system for transmitting data in one direction from a data transmission device to a data reception device in view of the above-mentioned conventional problems. It is an object of the present invention to provide a data transmission system, a data transmission method, a data transmission device, and a data reception device that enable a data reception device to securely authenticate a data transmission device without recording a sequence number for each communication partner.

[0015]

According to the present invention, when data is transmitted in one direction from a data transmitting device to a data receiving device, a value that changes according to time is generated from the transmitted data in the data transmitting device and the data receiving device. Authentication is performed using this value.

That is, in the data transmission system according to the present invention, the first information conversion means for converting the transmission data into the first authentication information by the first conversion function, and the data converted by the first information conversion means. A data transmitting device including a data transmitting unit that transmits first authentication information together with the transmission data; a receiving unit that receives first authentication information transmitted together with the transmission data from the data transmitting device; The second information conversion means for converting the transmission data received by the second information conversion means into the second authentication information by the same first conversion function as the first information conversion means, and the second information conversion means Data comprising: authentication means for determining whether or not the first authentication information received by the receiving means is equal to the first authentication information; Characterized in that comprising the communication apparatus.

Further, in the data transmission system according to the present invention, first information conversion means for converting transmission data into first authentication information by a first conversion function, and the first information conversion means converts the first authentication information. A data transmitting device including a data transmitting unit that transmits first authentication information together with the transmission data; a receiving unit that receives first authentication information transmitted together with the transmission data from the data transmitting device; A second information conversion unit for converting the first authentication information received by the second authentication information into a second authentication information by a second conversion function using an inverse conversion function to the first conversion function;
An authentication unit that determines whether the second authentication information converted by the second information conversion unit is equal to the transmission data received by the reception unit, and authenticates the data transmission device if the transmission data is received by the reception unit; And a data receiving device.

[0018] A data transmission method according to the present invention is a data transmission method for transmitting data from a data transmission device to a data reception device, wherein first information for converting transmission data into first authentication information by a first conversion function. A conversion step; a transmission step of transmitting the first authentication information converted in the first information conversion step together with the transmission data; and receiving the first authentication information transmitted together with the transmission data from the data transmission device. A second information converting step of converting the transmission data received in the receiving step into the second authentication information by the same first conversion function as the first information converting step; It is determined whether the second authentication information converted in the information conversion step is equal to the first authentication information received in the receiving step. And having an authentication step of authenticating the data transmission device.

Further, in the data transmission method according to the present invention, a first information conversion step of converting the transmission data into first authentication information by a first conversion function, and the first information conversion step converts the first authentication information. A transmitting step of transmitting the first authentication information together with the transmission data, a receiving step of receiving the first authentication information transmitted together with the transmission data from the data transmitting device, and a first step of receiving the first authentication information received in the receiving step. A second information conversion step of converting the authentication information into second authentication information by a second conversion function using an inverse conversion function to the first conversion function; and a second information conversion step of converting the authentication information into the second information conversion step. (2) determining whether or not the authentication information of step (2) is equal to the transmission data received in the receiving step, and if the transmission information is equal, authenticates the data transmitting apparatus. To.

[0020] A data transmitting apparatus according to the present invention comprises: an information conversion means for converting transmission data into first authentication information by a first conversion function; and a first authentication information converted by the information conversion means.
And data transmission means for transmitting the authentication information together with the transmission data.

[0021] A data receiving apparatus according to the present invention comprises: a receiving means for receiving transmission data sent together with first authentication information obtained by converting transmission data by a first conversion function; and a transmission means for receiving the transmission data received by the receiving means. An information conversion unit for converting data into second authentication information by the first conversion function, and the second authentication information converted by the information conversion unit is equal to the first authentication information received by the reception unit; Authentication means for judging whether or not the data transmission devices are equal to each other if they are equal to each other.

Further, a data receiving apparatus according to the present invention includes a receiving means for receiving transmission data transmitted together with first authentication information obtained by converting transmission data by a first conversion function, and a receiving means for receiving the transmission data. Converting the first authentication information into second authentication information using a second conversion function using an inverse conversion function to the first conversion function, and converting the first authentication information into second authentication information using the first conversion function. Conversion means;
An authentication unit that determines whether the second authentication information converted by the information conversion unit is equal to the transmission data received by the reception unit, and authenticates the data transmission device if the transmission data is equal to the second authentication information. And

[0023]

Embodiments of the present invention will be described below with reference to the drawings.

The present invention is applied to, for example, a data transmission system having a configuration as shown in FIG.

This data transmission system includes a data transmission device 10 and a data reception device 20, and the data transmission device 10 is transmitted via the transmission line 30 in one direction from the data transmission device 10 to the data reception device 20. And the data receiving device 20 are connected.

In the data transmission system of this embodiment, the data transmission device 10 is, for example, a set-top box that receives a satellite digital multi-channel broadcast program transmitted from a communication satellite, and is connected to an internal bus 11. Central processing unit (CPU: Central Processi
ng Unit) 12, memory 13, input interface 1
4, a user interface 15, an output interface 16, and the like. A satellite antenna 18 is connected to the input interface 14. The output interface 16 is connected to the transmission path 30.

In the data transmitting apparatus 10, the C
The PU 12 operates in accordance with the control program stored in the memory 13 and performs various control operations such as a program selection operation in accordance with operation information input via the user interface 15. I have.

The data transmitting apparatus 10, that is, the set-top box, selects a channel of a desired program of the satellite digital multi-channel broadcast signal by the input interface 14 to which the receiving antenna 18 is connected, and performs the desired program. The digital video signal is received, and the digital video signal of the received program is transmitted from the output interface 16 to the transmission path 30.

The data receiving device 20 is a recording device for recording a digital video signal of a program received by the data transmitting device 10, ie, a set-top box, on a recording medium such as a magnetic tape or a magneto-optical disk. The central processing unit (C
PU: Central Processing Unit) 22, memory 23, input interface 24, user interface 25,
It is composed of a media access unit 26 and the like. The transmission path 30 is connected to the input interface 24.

In the data receiving device 20, the C
The PU 22 operates according to a control program stored in the memory 23 and performs various control operations such as a recording operation by the media access unit 26 in accordance with operation information input via the user interface 25. It has become.

In this data transmission system, when the data receiving device 20 recognizes the validity of the data transmitting device 10 by the authentication processing, the data receiving device 20, that is, the recording device is connected to the input interface 24. The data transmission device 10 via the transmission path 30
The digital video signal sent from the storage device is recorded by the media access unit 26 on a recording medium such as the magnetic tape or the magneto-optical disk.

In this data transmission system, as described below, in order for the data receiving apparatus 20 to confirm the validity of the data transmitting apparatus 10, the data transmitting apparatus 10 and the data receiving apparatus 20 execute a conversion function f_k_12 (). Share, ISO / IE
In place of the value T-1 that changes depending on the time used in One pass authentication of C 9798-4 or the sequence number N-1 shared between the data transmitting device and the data receiving device, the transmission data data itself, Alternatively, using the value generated from the transmission data data, the ISO / IE
Performs authentication processing corresponding to C 9798-4 One pass authentication.

First, the operation of the data transmission device 10 will be described.

The data transmission apparatus 10, that is, the CPU 12 of the set-top box transmits the digital video signal of the received program as transmission data data from the output interface 16 to the data reception apparatus 20 via the transmission path 30. The control operation as shown in the flowchart of FIG.

That is, the CPU 1 of the data transmission device 10
2. First, the trigger signal indicating the start of data transmission is transmitted from the output interface 16 to the data receiving device 20 via the transmission path 30 (step S1).

Next, the CPU 12 sets the transmission data “data” to be transmitted from the output interface 16 to the data receiving device 20 via the transmission line 30 as D1 = data.
D1 is generated (step S2).

Next, the CPU 12 executes the step S
For the first information D1 generated in step 2, the conversion function f_k_12 ()
The first information conversion process of converting the first information D1 into the first authentication information Token12 is performed by performing an arithmetic process of Token12 = f_k_12 (D1) using (step S3). Here, the above conversion function f_k_12 ()
Is a conversion function shared with the data receiving device 20, and for example, a keyed hash function using k_12 as a key is used.

Then, the CPU 12 transmits the transmission data da
ta and the first authentication information Token1 converted in step S2.
2 from the output interface 16 to the transmission path 30
(Step S)
4).

Next, the operation of the data receiving device 20 will be described.

The data receiving device 20, ie, the recording device C
The PU 22 transmits the digital video signal transmitted from the data transmission device 10 through the transmission path 30 connected to the input interface 24 to the recording medium such as the magnetic tape or the magneto-optical disk by the media access unit 26. In recording, a control operation as shown in the flowchart of FIG. 3 is performed.

That is, the CPU 2 of the data receiving device 20
2 receives a trigger signal indicating the start of data transmission from the data transmission device 10 to the input interface 24 via the transmission path 30 (step S1).
1) In response to the trigger signal, reception of the transmission data "data" and the first authentication information Token12 is started, and the received transmission data "data" and the first authentication information Token12 are stored in the memory 13 (step S12).

Next, the CPU 22 executes step S
By setting the transmission data data received via the input interface 24 at D2 = D2 = data, the second information is obtained from the transmission data data.
D2 is generated (step S13).

Next, the CPU 22 executes step S
By setting the first authentication information Token12 received through the input interface 24 at Y at Y = Token12, a third information generation process for generating fourth information Y from the first authentication information Token12 is performed. Perform (Step S14).

Next, the CPU 22 executes step S
13, the conversion function f_k_12
The second information conversion process of converting the second information D2 into the second authentication information Z is performed by performing the operation process of Z = f_k_12 (D2) using the process (step S15).

Next, the CPU 22 executes step S
It is determined whether the fourth information Y generated in step 14, that is, the first authentication information Token12 is equal to the second authentication information Z generated by the second information conversion process in step S15 (step S16).

The CPU 22 determines that the result of the determination in step S15 is "YES", that is, when the fourth information Y, that is, the first authentication information Token12 and the second authentication information Z are equal. , The transmission path 3
0 and the first authentication information To
Recognizing the validity of the data transmission device 10 that has sent ken12, the data transmission device 10 transmits the transmission data da
The digital video signal sent as ta is recorded on the recording medium such as the magnetic tape or the magneto-optical disk by the media access unit 26 (step S17).

Further, the CPU 22 executes the processing in step S
15 is “NO”, that is, the fourth
If the first authentication information Token12 is not equal to the second authentication information Z, the transmission path 3
0 and the first authentication information To
The digital video signal transmitted as the transmission data data from the data transmission device 10 is discarded without recognizing the validity of the data transmission device 10 that has transmitted ken12 (step S18).

Here, the CPU of the data transmission device 10
In the step S2, instead of generating the first information D1 by setting D1 = data in the step S2, for example, using a hash function H (), an arithmetic processing of D1 = H (data) from the transmission data data is performed. To generate the first information D1, and in the first information conversion process of the step S2, the first information D1
The first information D1 may be converted into the first authentication information Token12 by performing an arithmetic process of Token12 = f_k_12 (D1) for D1.

In this case, the CP of the data receiving device 20
In step S13, instead of generating the third information D2 by setting D2 = data in step S13, the U22 uses a hash function H () to perform an arithmetic operation of D2 = H (data) from the transmission data data. The second information D2 is generated, and in the second information conversion processing in step S15, the second information D2 is subjected to an arithmetic processing of Z = f_k_12 (D2) to thereby convert the second information D2. It is converted to the second authentication information Z.

In steps S2 and S13, a cyclic code (CRC: Cyclic Redundancy) used for error detection instead of the hash function H () is used.
(Code) function may be used.

Here, the hash function is a function for outputting fixed-length data such as 64 bits or 128 bits for input data of an arbitrary length.
(x)), it is difficult to find x, and x1 such that hash (x1) = hash (x2)
It is a function that makes it difficult to obtain a set of x2 and x2. A typical one-way hash function is MD (Message D
igest) 5 and SHA (Soecure Hash Algorythm). For this one-way hash function, Bruce
Applied Cryptography (Second Edition) by Schneier, W
iley ".

In this data transmission system, ISO / IEC 97
Value T-1 that changes with time used in 98-4 One pass authentication or sequence number shared between data transmitter and data receiver
Using the transmission data data itself or a value generated from the transmission data data in place of N-1, the ISO / IEC979
By performing the authentication process corresponding to the one-pass authentication of 8-4, the data receiving device 20 can securely confirm the validity of the data transmitting device 10 without holding a clock or recording the sequence number of each communication partner. . Moreover, in this data transmission system, T-1 or N-1 in the information token12 sent from the data transmitting device 10 to the data receiving device 20 for the authentication process can be removed, so that the amount of communication data can be reduced. Can be.

Here, in the above description, in the above data transmission system, one pass aut of ISO / IEC 9798-4 is used.
Authentication processing corresponding to hentication is performed.
The data transmitting device 10 and the data receiving device 20 have a conversion function e_k_12 () and its inverse conversion function d_k_12 (), and the value that changes according to the time used in One pass authentication of ISO / IEC 9798-2. In place of T-1 or the sequence number N-1 shared between the data transmitting device and the data receiving device, the transmission data data itself or the value generated from the transmission data data is used, and the ISO / IEC is used. Authentication processing corresponding to One pass authentication of 9798-2 may be performed.

In the data transmission system, the IS
An operation of the data transmitting apparatus 10 when performing an authentication process corresponding to One pass authentication of O / IEC 9798-2 will be described.

The data transmission apparatus 10, that is, the CPU 12 of the set-top box transmits the digital video signal of the received program as transmission data data from the output interface 16 to the data reception apparatus 20 via the transmission path 30, as shown in FIG. The control operation shown in the flowchart of FIG.

That is, the CPU 1 of the data transmitting apparatus 10
2. First, the trigger signal indicating the start of data transmission is transmitted from the output interface 16 to the data receiving device 20 via the transmission path 30 (step S31).

Next, the CPU 12 sets D1 = data or D1 = H (data) from the transmission data data transmitted from the output interface 16 to the data receiving device 20 via the transmission line 30 to perform the first operation. Is generated (step S
32). Here, H () is a conversion function, and a hash function or a cyclic code (CRC: Cyclic Redundancy Code) function can be used.

Next, the CPU 12 executes step S
32, the conversion information e_k_12
The first information conversion process of converting the first information D1 into the first authentication information Token12 is performed by performing the calculation process of Token12 = e_k_12 (D1) using () (step S33). Here, the above conversion function e_k_12
() Is an encryption function using the key k_12, for example.

Then, the CPU 12 transmits the transmission data da
ta and the first authentication information Toke converted in step S32
n12 from the output interface 16 to the transmission line 3
0 to the data receiving device 20 (step S
34).

Next, the operation of the data receiving device 20 will be described.

The data receiving device 20, ie, the C of the recording device
The PU 22 transmits the digital video signal transmitted from the data transmission device 10 through the transmission path 30 connected to the input interface 24 to the recording medium such as the magnetic tape or the magneto-optical disk by the media access unit 26. In recording, a control operation as shown in the flowchart of FIG. 5 is performed.

That is, the CPU 2 of the data receiving device 20
2 receives a trigger signal indicating the start of data transmission from the data transmission device 10 to the input interface 24 via the transmission path 30 (step S4).
1) In response to this trigger signal, reception of the transmission data data and the first authentication information Token12 is started, and the received transmission data data and the first authentication information Token12 are stored in the memory 23 (step S42).

Next, the CPU 22 executes step S
By setting the transmission data data received via the input interface 24 at D2 = data or D2 = H (data) at 42, the second information is obtained from the transmission data data.
D2 is generated (step S43).

Next, the CPU 22 executes step S
By setting the second information D2 generated in 43 as Y = D2, the second information D2 is converted to the third information Y from the second information D2.
Is generated (step S44).

Next, the CPU 22 executes step S
For the first authentication information Token12 received via the input interface 24 at 42, the conversion function e_
By performing an operation of Z = d_k_12 (Token12) by an inverse transformation function d_k_12 () for k_12 (), for example, a decryption function using the key k_12, the first authentication information To
A second information conversion process of converting ken12 into the second authentication information Z is performed (step S45).

Here, the second authentication information Z obtained by the second information conversion processing is the first authentication information Token12 obtained by converting the first information D1 by the conversion function e_k_12 ().
, The inverse transformation function d_ for the above transformation function e_k_12 ()
Since it is inversely transformed by k_12 (), it is equal to the first information D1.

Next, the CPU 22 proceeds to step S
It is determined whether or not the third information Y generated in 44 is equal to the second authentication information Z generated by the second information conversion processing in step S45 (step S46).

Then, the CPU 22 determines that the determination result in the step S45 is "YES", that is, the third information Y, that is, the second information D2, and the second authentication information Z, that is, the first information D1, Are equal to each other, the data transmission device 10 that has transmitted the transmission data data and the first authentication information Token12 through the transmission path 30.
The digital video signal transmitted as the transmission data data from the data transmission apparatus 10 is recorded on the recording medium such as the magnetic tape or the magneto-optical disk by the media access unit 26 (step S4).
7).

Further, the CPU 22 determines in step S
45 is "NO", that is, the fourth
If the information Y and the second authentication information Z are not equal,
The transmission data data and the first
The digital video signal transmitted from the data transmission device 10 as the transmission data data is discarded without recognizing the validity of the data transmission device 10 that has transmitted the information Token12 (step S48).

As described above, one pass a of ISO / IEC 9798-2
uthentication, the value T-1 that changes depending on the time or the sequence number N-1 that is shared between the data transmitting device and the data receiving device, instead of the transmission data data itself, or from the transmission data data Using the generated value, One passau of ISO / IEC 9798-2 above
By performing authentication processing corresponding to thentication,
The data receiving device 20 can safely confirm the validity of the data transmitting device 10 without holding a clock or recording the sequence number of each communication partner.

[0071]

As described above, according to the present invention, when data is transmitted in one direction from the data transmitting apparatus to the data receiving apparatus, the data transmitting apparatus and the data receiving apparatus generate values that change according to time from the transmitted data. By performing authentication processing using this value, the data receiving apparatus can securely confirm the validity of the data transmitting apparatus without holding a clock or recording the sequence number of each communication partner.

That is, the transmission data is converted into the first authentication information by the first conversion function on the data transmitting device side, the first authentication information is transmitted together with the transmission data, and the data receiving device side transmits the first authentication information. The first authentication information sent together with the transmission data is received, and the received transmission data is converted to the second authentication information by the same first conversion function as the data transmission device.
It is determined whether or not the second authentication information is equal to the received first authentication information. If the second authentication information and the received first authentication information are equal, the data transmission device is authenticated. The data receiving device can safely confirm the validity of the data transmitting device without recording the sequence number for each.

Therefore, according to the present invention, when constructing a data transmission system for transmitting data in one direction from a data transmitting device to a data receiving device, the device may have a clock or record a sequence number for each communication partner. In addition, it is possible to provide a data transmission system, a data transmission method, a data transmission device, and a data reception device that enable a data reception device to securely authenticate a data transmission device.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a data transmission system to which the present invention has been applied.

FIG. 2 is a flowchart showing a control content of a transmission operation on a data transmission device side in the data transmission system.

FIG. 3 is a flowchart showing control contents of a receiving operation in a data receiving device in the data transmission system.

FIG. 4 shows the data transmission system according to ISO / IEC 97
48 is a flowchart showing the control contents of the transmission operation on the data transmitting device side when performing an authentication process corresponding to One Pass Authentication of 98-4.

FIG. 5 shows the data transmission system according to the ISO / IEC 97
48 is a flowchart illustrating the control content of the transmission operation on the data receiving device side when performing an authentication process corresponding to One-pass authentication of 98-4.

[Explanation of symbols]

10 data transmission device, 20 data reception device, 30
Transmission paths 30, 11, 21 Internal bus, 12, 22 CP
U, 13, 23 memory, 14, 24 input interface, 15, 25 user interface, 16
Output interface, 18 satellite antenna, 26 media access unit

Claims (14)

[Claims] The transmission data is converted to a first data by a first conversion function.
First information conversion means for converting the authentication information into
A data transmitting unit for transmitting the first authentication information converted by the information converting unit together with the transmission data; and receiving the first authentication information sent together with the transmission data from the data transmitting unit. Receiving means, a second information converting means for converting the transmission data received by the receiving means into second authentication information by the same first conversion function as the first information converting means, Data comprising an authentication means for judging whether or not the second authentication information converted by the information conversion means and the first authentication information received by the reception means are equal, and when they are equal, authenticating the data transmission device; A data transmission system comprising a receiving device. 2. The first information conversion means generates second information from transmission data using a second conversion function, and converts the second information into first authentication data using the first conversion function. The second information converting means converts the transmission data received by the receiving means into the second data which is the same as the first information converting means.
2. The data transmission system according to claim 1, wherein the second information is generated by a conversion function, and the second information is converted into second authentication data by the first conversion function. 3. The transmission data is converted to a first data by a first conversion function.
First information conversion means for converting the authentication information into
A data transmitting unit for transmitting the first authentication information converted by the information converting unit together with the transmission data; and receiving the first authentication information sent together with the transmission data from the data transmitting unit. And a second conversion function using an inverse conversion function to the first conversion function to convert the first authentication information received by the reception means into a second
Second information conversion means for converting the authentication information into
A data receiving apparatus comprising: an authentication unit that determines whether the second authentication information converted by the information conversion unit is equal to the transmission data received by the reception unit, and authenticates the data transmission device when the transmission data is equal. A data transmission system comprising: 4. The first information conversion means generates second information from transmission data using a second conversion function, and converts the second information into first authentication data using the first conversion function. The second information converting means converts the first authentication information received by the receiving means into the second information which is the same as the first converting means.
4. The data transmission system according to claim 3, wherein the second information is generated by using the conversion function of (1), and the second information is converted into the second authentication data by the first conversion function. 5. A data transmission method for transmitting data from a data transmission device to a data reception device, comprising: a first information conversion step of converting transmission data into first authentication information by a first conversion function; A transmitting step of transmitting the first authentication information converted in the information converting step together with the transmission data; a receiving step of receiving the first authentication information transmitted together with the transmission data from the data transmitting device; A second information conversion step of converting the transmission data received in the step into the second authentication information by the same first conversion function as the first information conversion step; and a second information conversion step. It is determined whether or not the second authentication information is equal to the first authentication information received in the receiving step, and if they are equal, the data transmitting apparatus is authenticated. Data transmission method characterized by having a testimony step. 6. In the first information conversion step, second information is generated from transmission data by a second conversion function,
The second information is converted into first authentication data by the first conversion function. In the second information conversion step, the transmission information received in the reception step is the same as the first information conversion step. Generating second information by a second conversion function;
6. The data transmission method according to claim 5, wherein said second information is converted into second authentication data by said first conversion function. 7. The transmission data is converted to a first data by a first conversion function.
A first information conversion step of converting the first authentication information converted in the first information conversion step together with the transmission data; and a transmission step of transmitting the first authentication information converted in the first information conversion step together with the transmission data. Receiving the received first authentication information, and converting the first authentication information received in the receiving step by a second conversion function using an inverse conversion function to the first conversion function. A second information conversion step of converting to the authentication information; and determining whether or not the second authentication information converted in the second information conversion step is equal to the transmission data received in the receiving step. An authentication step of authenticating the data transmission device. 8. In the first information conversion step, first information is generated from transmission data by a second conversion function,
The second information is converted into first authentication data by the first conversion function. In the second information conversion step, the first information conversion is performed based on the first authentication information received in the reception step. Generating the second information by the same second conversion function as the step,
The second information is converted into the second authentication data by the first conversion function. In the authentication step, whether the second information generated in the information conversion step is equal to the second authentication information is determined. 8. The data transmission method according to claim 7, wherein the data transmission device is authenticated if the values are equal. 9. The transmission data is converted to a first data by a first conversion function.
A data transmission device comprising: an information conversion unit that converts the first authentication information into the authentication information; and a data transmission unit that transmits the first authentication information converted by the information conversion unit together with the transmission data. 10. The information conversion means generates second information from transmission data using a second conversion function, and converts the second information into first authentication data using the first conversion function. The data transmission device according to claim 9, wherein: 11. A receiving means for receiving transmission data transmitted together with first authentication information obtained by converting transmission data by a first conversion function, and transmitting the transmission data received by the receiving means to the first conversion function. Information conversion means for converting to the second authentication information by a function; determining whether the second authentication information converted by the information conversion means is equal to the first authentication information received by the receiving means, An authentication unit for authenticating the data transmission device when the two data are equal to each other. 12. The information converting means generates second information from the transmission data received by the receiving means using a second conversion function, and converts the second information into a second information using the first conversion function. The data receiving apparatus according to claim 11, wherein the data is converted into authentication data. 13. A receiving means for receiving transmission data transmitted together with first authentication information obtained by converting transmission data by a first conversion function, and transmitting the first authentication information received by the receiving means to the first authentication information. An information conversion means for converting to the second authentication information by the first conversion function for converting to the second authentication information by a second conversion function using an inverse conversion function for the first conversion function; A data receiving apparatus for determining whether or not the converted second authentication information is equal to the transmission data received by the receiving means, and authenticating the data transmitting apparatus if the data is equal, . 14. The receiving means according to claim 3, further comprising:
Receiving the transmission data sent together with the first authentication information converted by the first conversion function from the first information generated by the conversion function, and the information conversion unit receives the transmission data received by the reception unit. Generating second information from the data using a second conversion function, converting the second information into second authentication data using the second conversion function, wherein the authentication unit is generated by the information conversion unit; 14. The data receiving apparatus according to claim 13, wherein it is determined whether or not the second information and the second authentication information are equal to each other, and if the two are equal, the data transmitting apparatus is authenticated.