JPH0732975A - Lock releasing signal making device and lock releasing device - Google Patents

Abstract

PURPOSE:To make decoding impossible, and thereby prevent burglar by letting the device be equipped with a memory means, a code producing means and with a means outputting a first and a second produced code to the outside. CONSTITUTION:A transmitter 100 allows a transmitting circuit 101 to transmit coded 'fixed numbers' and 'code numbers' to a receiving side via an antenna 102. At the side of an automobile as a receiver, it is equipped with an antenna 201 receiving electric waves from the transmitter, a receiving circuit 202 and with a decoding mechanism 203. The receiving circuit 202 receives the coded 'fixed numbers' and 'code numbers' so as to compound them. The receiving circuit 202 stores the 'fixed numbers' and 'code numbers', the stored 'fixed numbers' and 'code numbers' are compared with the compounded 'fixed number' and 'code number', and it is then determined whether or not the lock is released.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lock release signal transmitting device for outputting a signal for remotely releasing a door lock of an automobile, and a lock release device for receiving the signal to release the lock. Relates to prevention of plagiarism of release.

[0002]

2. Description of the Related Art In recent years, a so-called "keyless entry system" using radio waves or infrared rays has been put into practical use in door lock devices for automobiles, etc., in place of conventional unlocking mechanisms using mechanical or electronic keys. ing. This system stores a "fixed number", which has a unique value for each vehicle, in a transmitter in place of a key, and transmits this fixed number to the vehicle. The car side is also given a unique "fixed number" for the car in advance, and unlocks only when the fixed number on the car side and the fixed number sent from the transmitter match.

However, this fixed number has a weak defense effect against theft because it is easy to decipher what is sent from the transmitter. Therefore, Japanese Patent Laid-Open No. 1-
In No. 287671, a "code number" is provided in addition to the "fixed number", the fixed number and the code number are transmitted from the transmitter side, and the "fixed number" and "code number" received by the receiving side (vehicle side) Are checked to determine whether or not the cancellation is appropriate. That is, the transmitter sends the same fixed number each time, but the "code number" is changed and sent according to a certain algorithm every time it is sent.

For example, if the algorithm is to add a predetermined value α, the current "code number" is "1".
If it is 000 ", the transmitter and the receiver will receive" 100 ".
0 ”is stored, and the transmitter transmits“ 1000 + α ”as a code number in addition to the fixed number.
The receiving side is set to be transmitted with the code number α added from the transmitter side. Therefore, the receiving side, after confirming the fixed number, further compares the previously stored code number “1000” with the received code number “1000 + α”, and the difference is within the predetermined value. If so, the person who operated the transmitter is recognized as a legitimate person and is released. Here, on the receiving side, assuming that the transmitter may have already transmitted several times, for example,
If a code number with a difference within α ”is received from the transmitter side, it is determined to be normal.

[0005]

However, in such an encoding method (hereinafter, referred to as "rolling code method"), since only one "code number" is code-converted, the conversion rule is Once decrypted, it is easy to illegally duplicate code numbers.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned drawbacks of the prior art, and an object thereof is to propose an unlocking signal transmitting device and an unlocking device having a code which is difficult to decipher. It is a thing. In order to solve the above-mentioned problems and to achieve the object, an unlock signal sending device for sending a signal for unlocking according to the present invention is a first code unique to this remote unlock signal sending device. And a storage means having an area for storing a second code which is changed every time the device is operated, and a predetermined first operation is performed on the first code to generate a first code. First code generating means, second code generating means for performing a second predetermined operation on the second code to generate a second code, the generated first code and the second code Two
And a means for outputting the code of 1 to the outside.

For example, when sending to a receiver such as a vehicle, since two codes are encoded and sent, it is difficult to decode the codes. Further, according to the lock releasing device of the present invention, which receives the signal for releasing the lock transmitted from the external device and releases the lock, the signal is the encrypted first device unique to the lock circling device. And an encrypted second code that is progressively changed each time the external device is operated, and the encrypted first code is received with respect to the received first encrypted code. The first restoring means for performing the restoring process based on the second code, the second restoring means for restoring the encrypted second code, and the restored first code are unique to this releasing device. It is provided with a collating means for collating with the code, and collating with the restored second code for progressing and stored in the canceling device. .

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 shows a remote unlocking system according to an embodiment of the present invention. In the figure,
Reference numeral 100 denotes a transmitter, which transmits a "fixed number" and a "code number" that are encrypted as will be described later.
1 transmits to the receiving side via the antenna 102. 200
Is a car on the receiving side, and has an antenna 201 for receiving radio waves from a transmitter, a receiving circuit 202, and a releasing mechanism 203. The reception circuit 202 receives the encrypted “fixed number” and “code number” and decrypts them. The receiving circuit 202 stores a “fixed number” and a “code number”, and stores the stored “fixed number” and “code number” and the decoded “fixed number” and “code number”. By collating, it is determined whether or not the lock is released. When transmission is performed on the transmitter side, the code number is updated on the transmitter side in the nonvolatile memory 1
At 03. If the transmitter 100 and the receiving circuit 202 on the receiving side can be matched, the “code number” is updated, and the updated “code number” is stored in the nonvolatile memory 204. In the embodiment, these memories have an EEPROM (electrically erased memory).
I am able to use programmable ROM).

The transmitter 100 is provided with four keys W, X, Y and Z. The encryption method will be described. The encryption method of this embodiment is as follows: First, the code number is updated. : An arithmetic operation process or a logical operation process is performed on each digit of the updated code number and each digit of the fixed number.

The encryption method will be described in more detail. For convenience, the fixed number is 4 digits of abcd and the code number is 4 digits of ABCD. It depends on the key pressed on the transmitter 100. The code number of is changed by this code number = previous code number + α = abcd + α (1). However, α is an integer. The new code number abcd + α is represented by a four-digit a'b'c'd '. The process of encrypting the fixed number is different depending on which key the operator operated. For example, if the X key is pressed, the first digit = A OR a ′ second digit = B OR b ′ third digit = C OR a ′ fourth digit = D OR d ′ (2) Compute each digit of. For convenience, the fixed number changed in this way will be referred to as the "change number".
Call.

FIG. 2 shows the structure of data sent from the transmitter 100 to the receiving circuit 202. This data is in a frame format consisting of three fields,
These are “function number”, “change number”, and “code number” in that order. The function number field stores data indicating which key is pressed. In the example of FIG. 1, since four keys are prepared, the "function number" field consists of 2 bits: 00: W key 01: X key 10: Y key 11: Z key. The receiving circuit 202 can know which key the operator operated from the received "function number". The receiving circuit 202 has a memory 204 inside, and the memory 204
"Fixed number" and "code number" at the time of the last communication
I remember. Therefore, if the “function number” is “0” from the received “function number” and the “fixed number” and “code number” stored in the memory 204, the reception circuit 202 receives
If it indicates "1", it means that the change number is generated by the logical sum of the "fixed number" and the "code number" in the transmitter. The fixed number is restored by calculating the subtraction of the "code number". That is, restoration fixed number = (change number) and (received code number)
It is the inverse operation of and. The restored fixed number is collated with the fixed number stored (memory 204) on the receiving side. If they match, the fixed numbers are considered to match. next,
On the receiving side, the received code number = stored code number + α is collated. In this way, if the fixed number and the code number can be compared with each other, it is determined that the proper operation is performed, and the lock is released.

By the way, in the transmitter, any key may be pressed in an unexpected state. In such a case, the code number is updated only on the transmitter side and not on the receiving side. Then, in actual communication, the code number sent from the transmitter and the code number generated on the receiving side do not match on the receiving side. For example, the operator carelessly 1
If the key is pressed 0 times, a difference of 10α will occur between the transmitter side and the receiving side.

In order to avoid such inconvenience, restoration on the receiving side is performed as follows. That is, if the fixed numbers restored with the code number + α do not match, the code number +2
The fixed number is restored as α and collated. Such an operation is repeated up to + 100α. That is, it is assumed that the code number of this time obtained at the time when the fixed numbers match with each other is obtained when the previous code number <reception code number ≤ previous code number + n. However, n = 100α. Specifically, the number from the transmitter is +101
If the number is α and the number generated by the receiving side is + α, the receiving side has performed a meaningless operation 100 times before the operator, but the difference is n (= 100α) or less. Interpret it as a regular operation and unlock it. However, when the number from the transmitter is A + 102α, the difference is 101α, which exceeds n, so that it is judged to be illegal use and is not released.

Encryption of a fixed number when the key W is pressed, that is, generation of a change number is performed as follows. First digit = A XOR a ′ Second digit = B XOR b ′ Third digit = C XOR a ′ Fourth digit = D XOR d ′ (3) That is, a logical product is performed for each digit. When the Y key is pressed, change number = ABCD + a'b'c'd '(4) That is, the arithmetic sum is calculated. When the Z key is pressed, change number = ABCD-a'b'c'd '(5). That is, subtraction is performed.

FIG. 3 shows the structure of the transmitter 100, FIG. 4 shows the structure of the receiving circuit 202, and FIG.
00, and FIG. 6 shows the operation of the receiver 202. The transmitter 101 includes a battery power source, an internal antenna 102, a non-volatile memory 103, and an oscillator circuit 10.
4, a CPU 105, a reset circuit 106, and the like.
Further, the transmission circuit 202 is supplied with power from the battery of the vehicle body, and its voltage is used as a constant voltage by the power supply circuit 208. Furthermore, an antenna 201 that receives radio waves from the transmitter, a receiving unit 210 that detects and amplifies the received radio waves, a reset circuit 209 that resets the CPU 207 when the power is turned on, and a non-volatile memory 204 that stores a code number and a fixed number, And an output circuit 206 for generating a signal for releasing the lock.

First, the operation of the transmitter will be described. When any one of the key switches W, X, Y, and Z is pressed, the reset circuit 106 sends a reset pulse to the CPU 105. When reset pulse is input, CP
U105 starts operation. The operation of the CPU 105 is shown in FIG.
Will be described in accordance with the flowchart of FIG. First, CP
U105 performs initial setting (step S2). CPU
The 105 stops the reset circuit 106 with this initial setting. In step S4, the fixed number and the code number are read from the memory 103. As described above, the fixed number is given to each transmitter and is invariable, whereas the code number is updated every time the switch is pressed.

In step S6, the code number is updated according to the equation (1). In step S8, W, X, Y, Z
It is determined which key of the keys has been pressed. The function number is determined according to this determination. In step S10, it is determined which of the expressions (2) to (5) is to be used to create the change number according to the pressed key, and the change number is generated according to the expression determined in step S12. In step S18, the code number generated in step S6 is stored in the memory 103.
To update and store. In step S18, a pulse number is converted into a pulse number in the order of the function number, the change number, and the code number according to the format shown in FIG. The number of times the radio wave is emitted is once or several times. When the output of data is completed, the CPU 10
5 stops its function and returns to the switch input waiting state.

The operation of the receiver will be described with reference to the flowchart of FIG. The CPU 207 performs initialization at step S30, and then waits for reception from the transmitter at step S32. The receiving unit 210 detects and amplifies the signal received by the antenna 201 to take out data, and sends the data to the CPU 207. When the CPU 207 receives the data, it sends it to the RAM in the CPU.
It is temporarily stored in (not shown) (step S36). In step S38, the fixed number is restored based on the received change number and code number according to the restoration method described above. In step S40, the fixed number restored from the change number received from the transmitter and the fixed number stored in the memory 204 are compared and collated.

If the fixed numbers do not match, it is determined that the fixed numbers are illegally used, and the input from the transmitter this time is ignored. If the fixed numbers match, in step S42, the received code number is compared with the stored previous code number, and the received code number is
It is checked whether the stored code number has been properly changed. In this embodiment, as described above, the change to the code number is added by α. Therefore, in step S42, it is checked whether or not the received code number is obtained by adding α to the stored code number. Since the method of changing the code number is not limited to this, for example, a change by a logical operation may be considered, and even in that case, the received code number in step S42 is the same as the stored code number. Check whether the operation has been performed. Step S4
If the code number is judged to be incorrect in 2
Ignore this use as it was made.

If the code number change is legitimate,
In step S44, it is checked how many times the received code number has been changed. As described above, this check is valid if the code number received is within the range of the previous code number <the received code number ≦ the previously received code number + 100α. And step S4
In step 4, the received code number is updated and stored in the memory 204. In step S46, the centralized control device 205 meets the release mechanism and sends a release signal.

On the other hand, if it is determined in step S38 that the code number has been changed more than 100 times, this input is ignored. Thus, according to the above-described embodiment: Since not only the code number but also the fixed number has been changed, it is extremely difficult to decipher the code number, so that fraudulent attempts are prevented. : The method of changing the fixed number is changed according to the key position on the transmitter side. By doing this, a fixed number,
The lock cannot be unlocked only by stealing the code number, making stealing more difficult. : Since the fixed number is changed based on the changed code number by the logical operation or the four arithmetic operations of the fixed number and the fixed number, the encryption becomes complicated and the decryption becomes substantially impossible. : By restricting the regular range of code numbers, even if the method for progressively changing code numbers is stolen, the receiving side can check this range to prevent unlocking by an unauthorized user.

The present invention is within the scope of the gist of the invention.
The present invention can be applied to modified or modified embodiments. For example: In the above embodiment, the fixed number and the code number are 4 digits, but the present invention is not limited to this. It may be 10 digits or 20 digits. : In the above embodiment, the fixed number and the code number have the same length, but they may have different lengths. For example, as shown in FIG. 7, the fixed number is 24 digits and the code number is 1
It can be 6 digits. In this case, the generation of the change number becomes a problem. Therefore, as shown in FIG. 7, the surrounding numbers are divided into groups of two digits, and if the key X is pressed, for example, I
The above calculation is performed for i, II and ii, ... VIII and viii. If the key W is pressed, for example, I and v
Do not do iii, II and i, III ... Do a random combination such as XII and v. Further, in the above embodiment, the progressive change of the code number on the transmitter side is performed by pressing the key, but this may be progressively changed by the return of the authentication signal from the receiving side. . This allows
Mismatches in code numbers between transmitter and receiver are reduced.

[0023]

As described above, according to the lock release signal sending device and the lock release device of the present invention, since the encryption is performed twice, the decryption is practically impossible and theft is prevented. To be done.

[Brief description of drawings]

FIG. 1 is a diagram showing the configuration of an automobile keyless entry system to which a lock release signal transmitting device and a release device of the present invention are applied.

FIG. 2 is a diagram for explaining a signal format transmitted from the transmitter (lock release signal transmitting device) of FIG.

FIG. 3 is a diagram illustrating a configuration of a transmitter according to an embodiment.

FIG. 4 is a diagram illustrating a configuration of an unlocking device according to an embodiment.

FIG. 5 is a flowchart illustrating an operation procedure of the transmitter according to the embodiment.

FIG. 6 is a flowchart illustrating an operation procedure of the release device according to the embodiment.

FIG. 7 is a diagram illustrating an encryption method used in a modified example.

Claims (4)

[Claims] 1. A lock release signal transmitting device for transmitting a signal for releasing a lock, comprising: a first code unique to the remote lock release signal transmitting device and changed every time the device is operated. Storage means having an area for storing a second code, and first code generation means for performing a predetermined first operation on the first code to generate a first code; Second code generation means for performing a second predetermined operation on the second code to generate a second code; and means for outputting the generated first code and second code to the outside. An unlocking signal transmitting device comprising: 2. The lock release signal transmitting device according to claim 1, wherein the second calculation is a fixed calculation known to the external lock device side. 3. The remote lock signal transmitting device further comprises a plurality of keys, the first operation is different for each of these keys, and the first generating means is for operating the keys. Generate the corresponding key code together,
The unlocking signal transmitting device according to claim 1, wherein the key code is also transmitted to the outside. 4. An unlocking device for unlocking by receiving a signal for unlocking transmitted from an external device, wherein the signal is an encrypted first device unique to the unlocking device. Code and a second encrypted code that is progressively changed each time the external device is operated, and the encrypted first code is received with respect to the received first encrypted code. A first restoration unit that performs restoration processing based on a second code, a second restoration unit that restores the encrypted second code, and the restored first code is unique to this release device. It is provided with a collating means for collating with the code, and collating with the restored second code for progressing and stored in the canceling device. Unlocking device.