KR20050029018A - Methods for authenticating and coding a controling code based on its check sum and system thereof - Google Patents

Abstract

A methods and a system for authenticating and coding control codes based on check sums are provided to prevent illegal duplication or exposure of the control code by defining the check sum using updated first and second authentication IDs. A system includes a transmitting device(100) for coding a control code and a receiving device(200) for performing control operations based on the received control code. An input portion(120) generates operation control codes according to key inputs. A storage portion(130) stores a look-up table having plural calculation results according to residues by dividing the check sum code. A calculator randomly generates a first authentication ID in response to the key inputs and generates the control code by forming a second authentication ID based on the prior first authentication ID stored in the storage portion. The calculator obtains a result from the look-up table using the result of division of the check sum as an index and encodes the obtained control code. A transmitter(140) modulates the control code generated by the calculator and transmits the result. The receiving device includes a receiver(240), a storage portion(230) and a calculator.

Description

Methods and authenticating and coding a controling code based on its check sum and system algorithm}

The present invention relates to a method and system for encrypting and authenticating a control code, and more particularly, to variably generating a checksum constituting a control code, and using the checksum as an encryption and decryption clue in a wide range. A method of encrypting and authenticating a control code, and a system for performing the same.

As is well known in the art, a remote control system is used in a manner of controlling a main device by transmitting a control code from a remote control device through wireless data communication using radio frequency or infrared (IR). This control method is usually achieved by sending a data format consisting of four parts: a header (or identification ID), status code, data, and check sum. The fixed code method for controlling the device is mainly used. However, the fixed code method has a disadvantage in that it is likely to be duplicated to the person with an impure intention from the outside.

In order to prevent this, a method of transmitting control code data generated by a remote controller using two-way communication has been proposed. In this method, data is sent and received in both directions according to a rule defined by a transmitting side and a receiving side, for example, a quiz method. Perform data communication in a way that verifies However, since this quiz method is always performed according to a predetermined rule, the encoding and decoding process, there is a problem that there is a fear that the control code is duplicated when this rule is exposed.

Another way to prevent duplication of control codes generated in the remote control is to roll a code that is not reused. The rolling code generated by the rolling method is generated by incrementing or decrementing it to a constant value and is not reused when the rolling code is the same as the previously used code. In this scheme, the transmitting side attaches a variable rolling code to the custom code and transmits it to the receiving side, and the receiving side determines whether the generated rolling code matches the rolling code transmitted from the transmitting side and whether the control code is duplicated. Judge. However, in the rolling method described above, there is a fear that the control code is duplicated when a certain amount of change in increment or decrement leaks.

In consideration of this point, Korean Patent Application No. 2000-70518 has been made. As disclosed in the specification of No. 70518, when the counter value of the control code sent to the transmitting device is greater than or equal to a predetermined size (e.g., 133) than the counter value stored in the receiving device, the received control code is authenticated and controlled. When the same control code is repeatedly received, the counter value obtained from the previous control code and the counter value of the newly received control code are the same to prevent duplication. .

However, since the method of authenticating the control code by the counter disclosed in No. 70518 is a method of encrypting and sending the counter constituting the control code by a predetermined rule, when the encryption method is exposed, the control code may be Replication problems will arise. To prevent this, the 70518 is configured to generate an imaginary number as part of the control code, and to rearrange the imaginary added control code with reference to the lookup table according to the mapping code and the private code. Therefore, the 70518 is implemented by adding an imaginary number to the control code and encrypting it, and a complicated process of descrambling it again. Therefore, the process of authenticating the control code in the receiving apparatus is also composed of a complicated procedure corresponding to this, which causes a problem of inhibiting the response speed of the system. In addition, since the 70518 has to store the mapping code and the private code separately in the non-volatile memory for encryption and decryption, there is a problem that causes a waste of memory. Furthermore, when the mapping code and the private code leak, There is room for control code duplication.

The present invention was devised to solve the above problems, and generates a checksum code constituting a control code variably by an ID code added to the control code, and uses the check sum as an encryption and decryption clue to generate a width. It is an object of the present invention to encrypt and authenticate a control code in a wide range.

In order to achieve the above object, an aspect of the present invention provides a method for encrypting a control code, and the encryption method of the present invention relates to a method for variably generating and encrypting a checksum code constituting a control code. a) storing, in a storage unit, a lookup table including a plurality of operation values and operation operations according to the remaining values obtained by dividing the check sum code constituting the control code by a divisor; (b) randomly generating a first authentication ID with a preset length, reading a code used as a first authentication ID in a previous encryption into the storage unit, and generating a control code by configuring a second authentication ID; ; (c) calculating a calculated value from the lookup table and a corresponding calculation operation according to a value obtained by dividing the checksum obtained from the first authentication ID and the second authentication ID constituting the control code generated by the divisor. Selecting from; And (d) encrypting the control code by calculating the control code and the calculated operation value according to a calculation operation.

Preferably, the control code provided by the present invention comprises an ID frame consisting of an identification ID, a first authentication ID, a second authentication ID; Operation control code; And checksum codes; Since the checksum code obtained from the first authentication ID and the second authentication ID is also composed of various variables. Therefore, the encryption of the present invention, in which the checksum is used as an encryption clue, can be performed at random in a wide range.

On the other hand, another aspect of the present invention provides a method for decrypting and authenticating a control code encrypted by the above-described method in a receiving apparatus, wherein the transmitting apparatus comprises: (a) a first authentication ID with a preset length; Generating randomly, storing a code used as a first authentication ID in a previous encryption in a storage unit, and configuring a second authentication ID to generate a control code; (b) an operation value from the lookup table stored in the storage unit according to a value obtained by dividing the checksum obtained from the first authentication ID and the second authentication ID constituting the control code generated by the divisor, and a corresponding operation; Selecting from the lookup table; And (c) encrypting the control code by calculating the control code and the calculated operation value according to a calculation operation, and modulating the control code and transmitting the control code wirelessly. Demodulating the control code transmitted from the transmission device and decrypting the encrypted control code by decrypting the control code in the reverse order performed by the transmission device with reference to the lookup table included in the storage unit; And (e) a checksum code obtained from the decoded codes ; Checks that the checksum codes of the control code and the decryption control code are the same, and if they are the same, identify the identification ID of the decoded control code and the identification ID stored in the storage of the receiving device; And comparing the second authentication ID recorded in the storage unit with the first authentication ID of the decoded control code to authenticate the received control code.

In still another aspect of the present invention, there is provided a system comprising a transmitting device for encrypting and transmitting a control code and a receiving device for performing a control operation according to a control code transmitted from the transmitting device, wherein the transmitting device comprises a plurality of operation buttons. An input unit configured to generate an operation control code corresponding thereto; A storage unit for storing a look-up table that includes a plurality of operation values and operation operations according to a remainder obtained by dividing the check sum code constituting the control code by a divisor; In response to the selection of the operation button, randomly generates a first authentication ID with a preset length, reads a code used as a first authentication ID in a previous encryption into the storage unit, and constitutes a second authentication ID; Generates a control code and encrypts the control code by selecting an operation value from the lookup table stored in the storage unit and a corresponding operation in the lookup table according to a value obtained by dividing the check sum constituting the control code by a divisor. An operation unit; And a transmitting unit modulating the encryption control code generated by the calculating unit and transmitting the modulation control code to the receiving apparatus through a wireless channel, wherein the receiving apparatus demodulates the encryption control code transmitted from the transmitting apparatus. ; A storage unit for storing the same lookup table as the lookup table included in the transmitter; A checksum code for decrypting the encrypted control code by decoding the demodulated control code in the reverse order performed by the transmitting apparatus with reference to the lookup table stored in the storage; and forming a decoded control code. Check whether the checksum code is the same, and if it is the same, check whether the identification ID of the decoded control code and the identification ID stored in the storage unit are the same; ID; and an operation unit for comparing the first authentication ID of the decoded control code with each other to authenticate the received control code.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, terms or words used in the specification and claims should not be construed as having a conventional or dictionary meaning, and the inventors should properly explain the concept of terms in order to best explain their own invention. Based on the principle that can be defined, it should be interpreted as meaning and concept corresponding to the technical idea of the present invention.

Therefore, the embodiments described in the specification and the drawings shown in the drawings are only the most preferred embodiment of the present invention and do not represent all of the technical idea of the present invention, various modifications that can be replaced at the time of the present application It should be understood that there may be equivalents and variations.

1 is a block diagram of a system composed of a transmitter and a receiver according to the present invention.

The transmitting device 100 is composed of a device for encrypting the control code 300 in accordance with the present invention and transmitting in a wireless channel, the receiving device 200 decrypts the control code transmitted by encrypting in the transmitting device according to the present invention And an apparatus for performing operation control of an operation unit configured as part of a receiving apparatus according to an operation control code recorded as part of the control code.

First, the transmitter 100 includes a controller 110, an inputter 120, a storage 130, and a transmitter 140. The controller 110 generates a series of control codes related to the operation control of the receiving apparatus 200 with reference to the lookup table 131 included in the storage 130. 2 shows in detail the format of control code data constructed in accordance with the present invention. Referring to FIG. 2A of FIG. 2, the control code data 300 of the present invention includes an ID frame 310, an operation control code 320, and a check sum code 330. Again, the ID frame 310 is composed of an identification ID 311, a first authentication ID 313, and a second authentication ID 315 (see FIG. 2B). The identification ID 311 is set to a different code value for each system and used as a code for firstly authenticating the transmitting apparatus 100 and the main apparatus 200. On the other hand, the length of the control code 300 is a key factor in determining the security matters. Therefore, the longer the length, the higher the security, but it is difficult to implement, it is desirable to determine by introducing the concept of ordinary probability. Since this part is not directly related to the present invention, a detailed description thereof will be omitted, and the following description will be given with a security level of 4 bytes.

In the present invention, the first authentication ID 313 and the second authentication ID 315 constituting the ID frame 310 are generated so as not to overlap with any value in the order programmed internally in the controller 110. . In the present invention, the ID frame 310 is information related to the second authentication, the first authentication ID 313 is used to authenticate the control code 300 is transmitted from the current transmission device 100 to the source device 200 The second authentication ID 315 is stored in the receiving apparatus 200 in order to authenticate the control code generated by the transmitting apparatus 100 and then transmitted from the transmitting apparatus 100. The code 300 is compared with the first authentication ID 313 of the ID frame 310. Finally, the check sum code 330 constituting the control code 300 is used as a clue of the decoding process. This will be described later.

Referring back to FIG. 1, the storage unit 130 may include a non-volatile memory (ROM) and a volatile memory (RAM), and the ROM includes a lookup table (referenced to encrypt the control code 300). 131). As illustrated in detail in FIG. 3, the lookup table 131 includes arithmetic operations and arithmetic values used to encrypt a control code, and includes only arithmetic operations in a lookup table included in the transmission apparatus 100. Correspondingly, it is preferable that only the decoding operation is recorded in the reception apparatus 200. The RAM constituting the storage 130 temporarily stores the control code generated by the controller 110 according to an operation button of the input unit 120 selected by the user. On the other hand, the storage unit 130 further stores the operation control code data 133 generated according to the selection of the operation button provided in the input unit 120.

On the other hand, the input unit 120 is configured to include a plurality of operation buttons. The operation button provided in the input unit 120 is used as a button selected by a user to remotely control the operation unit 290 provided in the receiving apparatus 100. The operation control code 133 corresponding to the button selected by the user is configured as part of the control code 300 in the controller 110 and transmitted to the receiving device 200.

Next, the transmitter 140 modulates the control code 300 encrypted by the controller 110 with reference to the lookup table 131 in a normal modulation scheme and transmits the modulated control code 300 to the receiver 200 through a wireless channel.

Hereinafter, a series of control code encryption processes performed by the control unit 110 of the present invention will be described in detail with reference to FIG. 4. 4 illustrates a process in which the transmitting device 100 generates an encrypted control code according to the present invention.

Referring to FIG. 4, the controller 110 does not overlap the first authentication ID 313 and the second authentication ID 315 having a 4-byte length among the frame ID 310 as illustrated in FIG. 2 as data to be encrypted. Does not generate a random code (S110). In FIG. 5, the first authentication ID 313 is illustrated as '00 00 00 01 'in hexadecimal notation, and the second authentication ID 315 is illustrated as '00 01 01 01'. Moreover, the code used as the second authentication ID in the previous encryption process is used as the first authentication ID 313.

Next, a process of encrypting the control code data 300 by the control unit 110 with reference to the lookup table 131 included in the storage unit 130 will be described.

Currently, the first authentication ID 313 and the second authentication ID 315 in the generated control code 300 are nibble unit bytes '00, 00, 00, 01 ', '00, It is set to 01, 01, 01 '. On the other hand, the second authentication ID 315 is a code that is newly obtained randomly every time the control code 300 occurs in the transmitting apparatus 100, the first authentication ID 313 is a second authentication ID generated in the previous transmission process . Then, the checksum code 330 obtained from the ID frame 310 and the operation control code 320 by a conventional method (shown in the drawing by XORing from the first byte value of the identification ID to the operation control code value). Is set to '51'. Therefore, since the check sum used as the encryption clue is obtained based on the first authentication ID 313 and the second authentication ID 315 having variable values, the check sum code is also updated every time the control code 300 is generated. It is obtained by value.

In operation S120, the control code 300 generated as shown in FIG. 5A is selected and encrypted as a corresponding operation operation and operation value in the lookup table 131. The remaining values obtained by dividing the checksum by 8 (hence, 0 to 7). Is selected from), and the byte-by-byte operation value of each code is obtained. In addition, the operation associated with the obtained value may be set by the preset bytes' ADD (311 (drawing number) _0 (number of digits per byte)), XOR (311_1), SUB (311_2), ADD ((311_3), XOR (313_0), SUB 313_1, ADD 313_2, XOR 313_3, SUB 315_0, ADD 315_1, XOR 315_2, and SUB 315_3 '.

Next, the operation value '5C 5D 5E 5F' obtained from the identification ID 311 '00 00 00 01 'and the lookup table 131 of the control code data 300 illustrated in FIG. 4A and the first authentication ID 313. '00 00 00 01 ', the operation value '60 61 62 63', the second authentication ID 315 '00 01 01 01 'and the operation value '64 BF C0 C1' are sequentially calculated according to the above-described operation. As a result, the control code illustrated in FIG. 5A is encrypted with code values as shown in FIG. 5B (S120 to S140).

Then, the control code encrypted through the above-described process (S110 to S140) is combined with the operation control code 320 generated by the selection of the selection button constituting the input unit 120 by the user, the transmission unit 140 Is modulated and transmitted to the receiving device 200 via a wireless channel in the data format illustrated in FIG. 5B.

On the other hand, the receiving apparatus 200 has the same configuration as the transmitting apparatus 100 except for further including an operation unit 290 driven according to the control code 300 transmitted from the transmitting apparatus 100. Therefore, description of the same configuration is omitted. 6 illustrates a process of decrypting a control code encrypted and transmitted by a transmission apparatus according to the present invention.

Referring to FIG. 6, the controller 210 of the receiver 200 performs a process of decrypting the reverse of the encryption process performed by the transmitter 100 with reference to the lookup table 231 included in the storage 130. Decode the control code.

First, in step S210, the receiver 240 of the receiver 200 demodulates the control code data transmitted from the transmitter and applies it to the controller 210 (S210). At this time, the control code data demodulated by the receiving device 200 is the same as in Fig. 5b.

Then, in a next step (S220), the controller 210 refers to the remaining number obtained by dividing the check sum code 330 by eight of the demodulated control code data 300 by eight, and the lookup table 231 included in the storage 230. ), The operation value for each byte digit of the identification ID 311, the first authentication ID 313, and the second authentication ID 315 is obtained. The calculated result is '5C 5D 5E 5F' '60 61 62 63 ''64 BF C0 C1'. In addition, the operation associated with the value obtained through the step S220 is' SUB (311_0), XOR (311_1), ADD (311_2) corresponding to the operation operation that is preset and stored in the lookup table 231 for each byte, that is, the encryption operation operation. ), SUB ((311_3), XOR (313_0), ADD (313_1), SUB (313_2), XOR (313_3), ADD (315_0), SUB (315_1), XOR (315_2), ADD (315_3) ' Accordingly, the control code data 300 demodulated through the step S220 is decoded to the original data as shown in Fig. 5a.

Then, the control unit 210 checks constituting a code decoded through the above-described process, that is, a checksum code newly obtained from the ID frame 310 in the above-described manner (step S120 of FIG. 4) and the control code before demodulation. It is checked whether the island codes are the same (S230).

As a result, if the two codes do not match, the step ends. On the other hand, if the two codes match, it is next checked whether the identification ID of the storage unit 230 of the receiving apparatus 200 and the identification ID of the decoded control code data are the same. (S240), and then stores the first authentication ID of the decoded control codes and the two authentication IDs 135 stored in the storage unit 230 decoded from the control code transmitted by the transmitting apparatus 100 in the previous transmission process. Extracted from the unit 230 and compared with each other (S250). If the same is also checked, the second authentication ID 135 acquired and recorded in the previous authentication process in the storage unit is updated with the new second authentication ID obtained through the above-described decryption process (S260). The authentication process of the control code received from the transmitter 100 through the wireless channel is completed. On the other hand, this process (S260) is preferably generated according to the identification ID authentication by the process S240 is essential, the first authentication ID generated in the transmitting apparatus 100 and the receiving apparatus 200 due to a system error This is for resetting the ID code when the second authentication ID stored does not match. Therefore, although the process of updating the second authentication ID is shown as a step occurring after step S260 in the drawing, any step after step S240 may be performed.

Then, the receiving apparatus 200 performs an operation of controlling the operation unit 290 with reference to the operation code from the data stream of the operation control code 320 of the control code (S270).

As described above, although the present invention has been described by way of limited embodiments and drawings, the present invention is not limited thereto and is intended by those skilled in the art to which the present invention pertains. Of course, various modifications and variations are possible within the scope of equivalents of the claims to be described.

According to the present invention, since the first authentication ID and the second authentication ID constituted by the control code of the present invention are defined as always changing values, the check sums obtained by these values are also defined as new values every time. Therefore, there is no fear that the control code is exposed because the encryption is not made with a certain rule because the check sum used as the encryption clue is always changing. Moreover, the checksum obtained based on the first authentication ID and the second authentication ID also obtains the encryption operation value by referring to the remainder divided by a specific argument, so that there is no change and the control code is not duplicated or exposed. .

The following drawings attached to this specification are illustrative of preferred embodiments of the present invention, and together with the detailed description of the invention to serve to further understand the technical spirit of the present invention, the present invention is a matter described in such drawings It should not be construed as limited to

1 is a block diagram of a system constructed in accordance with the present invention.

2 shows a data format of a control code according to the present invention.

3 illustrates an example of a lookup table according to the present invention.

4 is a flowchart illustrating a process of encrypting a control code in a transmitting apparatus of the present invention.

5 shows a configuration example of control code data for explaining an encryption and decryption process of the present invention.

6 is a flowchart illustrating a process of decrypting and authenticating a control code in a receiving apparatus of the present invention.

* Brief description of the major symbols in the drawings *

100: transmitter 131: lookup table 200: receiver

300: control code 313: first authentication ID 315: second authentication ID

Claims (11)

A method of encrypting and encrypting a checksum code constituting a control code, (a) storing, in a storage unit, a look-up table including a plurality of operation values and operation operations according to a remainder obtained by dividing the check sum code constituting the control code by a divisor; (b) randomly generating a first authentication ID with a preset length, reading a code used as a first authentication ID in a previous encryption into the storage unit, and generating a control code by configuring a second authentication ID; ; (c) calculating a calculated value from the lookup table and a corresponding calculation operation according to a value obtained by dividing the checksum obtained from the first authentication ID and the second authentication ID constituting the control code generated by the divisor. Selecting from; And, (d) encrypting the control code by calculating the control code and the calculated operation value according to an operation. The method of claim 1, The control code includes an ID frame consisting of an identification ID, a first authentication ID, and a second authentication ID; Operation control code; And a checksum code. The method of claim 3, And the operation is defined corresponding to the number of digits for each byte constituting the ID frame. A method of encrypting and transmitting a control code generated by a transmitting device and authenticating a received control code with reference to a look-up table in a receiving device operating under control of the control code, The transmitter, generating a control code by randomly generating a first authentication ID with a preset length, reading a code used as a first authentication ID in a previous encryption into a storage unit, and configuring a second authentication ID; (b) an operation value from the lookup table stored in the storage unit according to a value obtained by dividing the checksum obtained from the first authentication ID and the second authentication ID constituting the control code generated by the divisor, and a corresponding operation; Selecting from the lookup table; And, (c) encrypting the control code by calculating the control code and the calculated operation value according to a calculation operation, and modulating the control code and transmitting the control code over the air; The receiving device, (d) demodulating the control code transmitted from the transmission device and decrypting the encrypted control code by decrypting the control code in the reverse order performed by the transmission device with reference to the lookup table included in the storage unit; And, (e) a checksum code constituting the decoded control code; and a checksum code obtained from the decoded codes; checks whether they are the same, and if it is the same, an identification ID of the decoded control code; Checking whether the stored identification ID is the same, and authenticating the received control code by comparing the second authentication ID obtained in the previous authentication process and stored in the storage unit with the first authentication ID of the decoded control code. Authentication method of the control code, characterized in that it comprises a. The method of claim 5, When the identification ID is authenticated in the step (e), the second authentication ID of the decoded control code is stored in the storage unit of the receiving apparatus and used for the next authentication process. Authentication method. The method of claim 5, The control code includes an ID frame consisting of an identification ID, a first authentication ID, and a second authentication ID; Operation control code; And a check sum code. The method of claim 6, And the operation is defined corresponding to the number of digits for each byte constituting the ID frame. A system comprising a transmitting device for encrypting and transmitting a control code and a receiving device for performing a control operation according to a control code transmitted from the transmitting device. The transmitting device, An input unit including a plurality of operation buttons and generating an operation control code corresponding thereto; A storage unit for storing a look-up table that includes a plurality of operation values and operation operations according to a remainder obtained by dividing the check sum code constituting the control code by a divisor; In response to the selection of the operation button, randomly generates a first authentication ID with a preset length, reads a code used as a first authentication ID in a previous encryption into the storage unit, and constitutes a second authentication ID; Generates a control code and encrypts the control code by selecting an operation value from the lookup table stored in the storage unit and a corresponding operation in the lookup table according to a value obtained by dividing the check sum constituting the control code by a divisor. An operation unit; And a transmitting unit for modulating the encryption control code generated by the calculating unit and transmitting the encrypted control code to the receiving apparatus through a wireless channel. The receiving device, A receiver which demodulates an encryption control code transmitted from the transmitter; A storage unit for storing the same lookup table as the lookup table included in the transmitter; Decrypts the encrypted control code by decrypting the demodulated control code in the reverse order performed by the transmitting apparatus with reference to the lookup table stored in the storage unit, and checksum code obtained from the decoded codes; Check whether the island code is the same, and if it is the same, the identification ID of the decoded control code and the identification ID stored in the storage unit are the same, and the second authentication ID obtained in the previous authentication process and stored in the storage unit. And an arithmetic unit for comparing the first authentication ID of the decoded control code with each other and authenticating the received control code. The method of claim 8, When the identification ID is authenticated in the step (e), the second authentication ID of the decoded control code is stored in the storage unit of the receiving apparatus and used for the next authentication process. Authentication method. The method of claim 9, The control code includes an ID frame consisting of an identification ID, a first authentication ID, and a second authentication ID; Operation control code; And a check sum code. The method of claim 10, And the operation is defined corresponding to the number of digits for each byte constituting the ID frame.