RU2019047C1 - Method of check of authenticity of discrete information - Google Patents

Abstract

FIELD: data transmission systems. SUBSTANCE: in transmission side check convolution of message and test block are formed depending on information contained in last information block. Last information block is coded with use of value of check convolution of message and last information block is substituted with code of information block. When receiving information message check convolution of information blocks up to last one is formed, according to code of information block and to value of check convolution last block of information message is decoded and result is compared with value of test block. Similar use of operations makes it possible to reduce time of check of authenticity when transmitting information message. EFFECT: reduced time of authenticity check. 6 dwg

Description

 The invention relates to data transmission systems and can be used at points of transmission, reception and processing of information to ensure its reliability.

 A known method of controlling the reliability of discrete information (Goncharov E.A. et al. About one method of encoding information with cyclic codes on a computer. Collection of scientific works TsNIIS. M .: 1970, N 3) consisting in the fact that on the transmitting side the information message is divided into information blocks, for each information block, a control convolution of the previous blocks is formed, and the control convolution value of the previous information blocks for the first information block of each information message is formed equal to the known on the receiving side the beginning, and for each block of information by its numerical value and the control convolution of the previous blocks of information, the code of the block of information is formed, and the transmitted message is supplemented by a check block.

 On the receiving side, the received message is divided into information block codes, for each information block code, a control convolution of the previous information block codes is generated, and the control convolution value of the previous information block codes for the first information block code is formed equal to the known value of the control convolution of the previous information blocks for the first information block corresponding informational message on the transmitting side. For each code of the information block, a decoded information block is formed by its numerical value and by the control convolution of the previous codes of information blocks, the received verification block is compared with the corresponding decoded information block and the decision on the reliability of the received information is made based on the results of the comparison.

 However, due to the fact that the additional verification unit is selected randomly and the method of its selection is not known on the receiving side, its deliberate change with the simultaneous change in the transmitted information can lead to false information. This drawback reduces the accuracy of the validation control.

 The prototype of the invention is a method for monitoring the reliability of discrete information (ed. St. USSR N 849523, class H 04 L 11/08, 1981), which consists in the fact that on the transmitting side the information message is divided into blocks of information, for each block of information form control a convolution of the previous information blocks, and the value of the control convolution of the previous information blocks for the first information block of each information message is formed equal to the value known on the receiving side, for each information block by its numbers th value and the control information forming the convolution previous block information code blocks, each block of information in the transmitted message block information code is replaced, and the transmitted message verification block complement. On the receiving side, the received message is divided into information block codes, for each information block code, a control convolution of the previous information block codes is generated, and the control convolution value of the previous information block codes for the first information block code is formed equal to the known value of the control convolution of the previous information blocks for the first information block corresponding informational message on the transmitting side. For each code of the information block, a decoded information block is formed by its numerical value and by the control convolution of the previous codes of information blocks, the received verification block is compared with the corresponding decoded information block and the decision on the reliability of the received information is made based on the results of the comparison.

 The known method provides sufficient accuracy of control of the received information, however, has a low speed. For the purposes of reliability control in the prototype, each block of information is encoded and replaced with the code of the block of information. However, since when monitoring the message on the receiving side only the last information block is used, it is enough to encode only it, and the rest of the information blocks, firstly, not to encode and secondly, not to replace with information block codes. This will allow, with the same control accuracy, to reduce the time both for transmitting an information message and for receiving it.

 The aim of the invention is to increase performance.

 This is achieved by the fact that with the known method of checking the reliability of discrete information, namely, that the information message is divided into information blocks on the transmitting side, a control convolution of the previous information blocks is formed for each information block, and the control convolution value of the previous information blocks for the first information block of each an information message is formed equal to the value known at the receiving side, and the transmitted information message is supplemented with a check block m, and on the receiving side, the received information message is divided into information blocks, a control convolution of the previous information blocks is formed for each information block, and the control convolution value of the previous information blocks for the first information block is formed equal to the value known on the receiving side, the verification block is compared with the corresponding block information and the results of the comparison decide on the reliability of the received information message, in it on the transmitting side for the last block As information on its numerical value and on the control convolution of the previous information blocks, an information block code is generated, the last information block in the transmitted information message is replaced by the received information block code, and on the receiving side, on the control convolution of the previous information blocks and the numerical value of the last information block code decoded block of information.

 In addition, on the transmitting side, an information block code is generated as a test block, the numerical value of which is equal to the numerical value of the last decoded information block on the receiving side.

 The method is as follows.

The information message to be transmitted to the communication channel is divided into AND blocks of information of equal volume. Then, a message convolution is formed in accordance with the irreversible function
Y = F (x) = E _xn (E _xn-1 . (... (E _x1 (c) ...))) The function Y = F (x) is irreversible in the sense that for any x from its domain of definition F (x) is easily computable, but for almost all y from its domain of values of finding x, for which y = F (x), it is computationally impracticable. As an irreversible function, the standard cryptographic transformation algorithms are used in accordance with GOST 28147-89. an irreversible function is equivalent to the strength of a standard cryptographic algorithm.

The convolution of the message is as follows. The first block of information is selected. The numerical value of the block is used as a conversion key, and the same number for both subscribers and senders is selected as the initial value of the control convolution for it. The convolution of the first information block is formed as
Y ₁ = E _x1 (c), where X ₁ is the numerical value of the first information block;
c is the initial value of the control convolution for the first information block;
E _x1 is a function that implements the standard cryptographic conversion algorithm.

 After that, a second block of information is selected, the numerical value of which is used as a cryptographic conversion key. A convolution of two blocks of the information message is formed.

Y ₂ = E _x2 (Y ₁ ).

When you select the last information block, a convolution is formed using the function
Y _n = E _xn (Y _n-1 )
After the convolution of the information message is generated, the last block of the information message is generated. To do this, firstly, choose a random number equal in size to the volume of the information block. Secondly, the selected random number is encoded in a special way. By coding is meant the replacement of the last block of information with the corresponding code of the block of information selected in a pseudo-random manner and having the same length. The choice of the code of the information block is carried out depending on the code of the selected random number and on the value of the received control convolution of the information message. The same cryptographic conversion standard according to GOST 28147-89 is used as a way to select the information block code, and the random number value is used as the conversion key, the number of cycles is set by the numerical value of the control convolution of the information message, and the initial value of the control convolution is used as the initial value for the first information block. The encoding of the last block of information is as follows.

 By the numerical value of the control convolution for the first information block and the value of a random number, the code of the block of the first cycle is selected according to the algorithm given in GOST 28147-89. Then, by the numerical value of the control convolution for the first information block and the block code of the first cycle, the block code of the second cycle is selected similarly to the first case. Encoding continues until a loop block code is received whose numerical value is equal to the numerical value of the control convolution of the information message. After coding, the last block of information is replaced with the code of the block of information and proceed to the formation of the verification block. The verification block is formed similarly to the last block of the information message, but the maximum possible value of the control convolution of the information message is used as the numerical value of the last cycle to obtain the code of the information block.

So, for example, if the volume of the control convolution of the information message is m bits, then its maximum possible numerical value is 2 ^m .

 The information message is supplemented by the received test block and sent to the communication channel.

After receiving the message from the communication channel, the control convolution of unencoded blocks of information is formed. Formation of the control convolution of the information message on the receiving side is carried out similarly to how it was done during transmission. After receiving the control convolution of the information message, they start decoding the last block of information. By the numerical value of the control convolution and by the value of the last code of the information block, the decoded last information block is selected in a pseudo-random way. The selection of the decoded information block is performed using the cryptographic conversion algorithm according to GOST 28147-89 in the same way as on the transmitting side. For this, the control convolution value for the first information block is used as the initial value, and the information block code is used as the conversion key. The moment of selection of the decoded information block (the number of conversion cycles) is determined by the number that is a complement to the value of the received convolution of the information message to its maximum value. If the convolution value is A, and its maximum value is 2 ^m (m is the convolution volume in bits), then the addition is D = 2 ^m - A. After decoding the last information block, its value is compared with the verification block. If their values coincide, then the received message is true, if their values do not match, then during the transfer process the message was amended and it is false.

 Thus, the exclusion from the sender of the message of operations of encoding all blocks of information, their replacement by codes of blocks of information, and the recipient of operations of decoding all blocks of information can reduce the time taken to control the reliability of the information message and thereby increase the speed of the method. On the other hand, the introduction of the encoding operation of the last block of information such that only by decoding it in a special way can the value of the check block be obtained, it is possible to ensure the accuracy of the control with the proposed method no worse than with the known method.

 The proposed method is illustrated by the structural diagram of a device for monitoring the reliability of discrete information (see Fig. 1), which is one of the options for implementing the proposed method, and functional diagrams of non-standard blocks included in its composition, such as a recording block (see Fig. 2) , a random number generator (see FIG. 3), a message generating unit (see FIG. 4), a conversion unit (see FIG. 5) and a control unit (see FIG. 6).

 The device for monitoring the accuracy of discrete information contains a recording unit 1, a random number generator 2, a buffer register 3, an AND 4 element, a clock pulse generator 5, a modulo two adder 6, a message generating unit 7, a conversion unit 7, a conversion register 8, an output register 9, an element And 10, the control unit 11, the block of elements And 12. The output of the clock generator 5 through the And 4 element connected to the output of the control unit 11 by the second input and the random number generator 2 are connected to the input of the recording unit 1, the second input of which is connected to the output b damn register 3, connected by a clocking input to the second output of the control unit 11, the output of the recording unit 1 is connected to the inputs of the message forming unit 7 and the unit 12 And through module 6 adders 6, the input of the conversion unit 8, the second input of which is connected to the third output of the control unit 11, the output of the conversion unit 8 is connected to the second inputs of the adder unit 6 modulo two and the message generating unit 7, the third input of which is connected to the fourth output of the control unit 11, the output of the message generating unit 7 connected to the inputs of the register 9 of the issue and the control unit 11, the second input of which is connected to the second output of the conversion unit 8, the output of the register 9 of the issue is connected to the second input of the unit 12 And, the third input of which is connected to the fifth output of the control unit 11, the sixth output of which connected to the input of the I10 element, and the seventh output to the third input of the recording unit, the second input of the I10 element is connected to the second output of the output register 9, the third input is connected to the output of the block of 12 And elements, and the third input of the control unit 11 is connected to the output of the generator 5 clock pulses.

 The recording unit 1 is intended for inputting information message blocks into the device for their further conversion. It is a set of selectors 13.1 ... 13.n (microcircuit 533KP11) that receive information from two directions. The direction is selected by signal V. At V = 0, the first direction is selected, at V = 1, the second.

 The random number generator 2 is designed to obtain a chaotic sequence of binary pulses. It can be performed according to the functional diagram shown in figure 3. The generator contains a diode 14, an amplifier 15, an element NOT 16, an AND element 17, a counter 18, an adder 19 modulo two, a D-trigger 20 and a register 21.

 The signal from the noise diode 14, which can be a diode 2G401A, is fed through an amplifier 15 to the element And17. In the absence of a clock pulse, the I18 element is open, and noise pulses are counted in the counter 18, and then are added modulo two on the adder 19.

 When a clock pulse arrives, the I17 element is closed, from the D-trigger 20, the value of its previous state is entered into the register 21 and the current value of the adder 19 is recorded modulo two.

 The buffer register 3 is intended for receiving and storing an information message block by signals from the control unit 11 and may contain a set of chips 533IR16, which are a universal shift register.

 Block 7 formation of the message is designed to enter blocks of information messages in the register 9 of the issuance in the required order. It contains a set of selectors 22.1 ... 22.n (m / s 533KP11) and universal shift registers 23.1, ..., 23.n (m / s 533 IR16).

 The signal supplied to the input "0" of the registers 23, records the number coming from the selector 22 in parallel, and then, when clock pulses are applied, to the input C, it moves to the block output from the last register 23.n. The direction on the selector 22 is selected at the input V.

Block 8 conversion is designed to form a convolution of the message, the coding of the last block of the message and the formation of the verification block of the information message. Block 8 conversion is an implementation of a cryptographic scheme in accordance with GOST 28147-89. It contains a selector 25 in three directions, registers 26, 28, 32, a selector in two directions 27, an arithmetic adder 29, a replacement unit 30, an adder unit 31 modulo two, counters 33, 36, a memory unit 34, a shaper 35, a decoder 37 , trigger 38. When the trigger signal arrives at the input of the driver 35, it starts generating a sequence of microtacts of the operation of the T ₁ -T ₅ block.

In this case, the input of the decoder 37 is zero, and the selector 25 receives information from the input of the block. By step T _{1, the} information block is written into register 26, from which, through selector 27, by step T _2, half of it is copied to register 28. By step T ₃ from the memory node, the first value of the conversion key is fed to the input of the arithmetic adder 29, where it is added to the first half information block. The summation result is sent to the replacement unit 30, which converts the code supplied to its input into some other code in accordance with the code stored in block 30. Programmable read-only memory devices (m / cx 556 PT4) can be used as storage elements for the replacement code , each of which replaces the four-bit word received at its address input, in a four-bit code, read at the corresponding address. The replacement result is added in block 31 of the adders modulo two with the second half of the information block stored in register 26, and recorded at register T ₄ in register 32. At cycle T _5, counters 33 and 36 change their state. In this case, the decoder 37 enters the state of receiving information in the selector 27 from the register 32, the selector 25 from the register 28, and the memory node 34 is transferred to the reading state of the second value of the conversion key. By step T ₁ , the contents of register 28 are rewritten into register 26, and by step T ₂ , the contents of register 32 are transferred to register 28 and the conversion cycle is repeated. After processing the penultimate value of the conversion key, the decoder 37 enters the state of receiving information from register 32 to selector 25 and from register 26 to selector 27. In this case, the result of the conversion is written to register 26 and output from block 8. in step T ₂ . of the decoder 37, the trigger 38 is reset and gives a signal of readiness for further operation of the unit.

 The control unit 11 is designed to control the operation of the device. It contains elements I 39,43,46,49, counters 40,52,58, decoders 41,51,59, trigger 42, shapers 45,53,54, elements OR 47,50, elements NOT 44,48, node 55 constants, blocks of 56.60 AND elements, block of 57 OR elements, block 61 of adders modulo two and switch 62. When transmitting a message, switch 62 is switched to position I, thereby allowing signals to be transmitted through element I49 and block 56 of elements I. Operation block starts at the start signal. In this case, the counter 52 is restored to its initial state, the clock pulses through the open element And 39 are sent to the counter 40. At the first cycle, the decoder 41 is activated and includes a trigger 42, which allows the passage of the clocks through the I43 element to the buffer register 3.

 After receiving the information block in the buffer register 3, the decoder 41 switches the trigger 42 to its original state. The shaper 45 is triggered by this signal and provides a signal to the message generating unit 7 and the conversion unit 8. The counter 52 counts the number of blocks of the information message. At the time of operation of the conversion unit, the AND element 39 is closed. After converting the next information block of signals from block 8, the I39 element is opened and the operation of the described chain of elements is repeated. When processing the penultimate block of the information message through the OR element 50 and the element NOT 48 is fixed, the value of a random number in the random number generator 2, in addition, the recording unit 1 and the message generation unit 7 through the AND 49 element are transferred to the information reception mode from another direction, and the signal from the decoder 51 through the shaper 54, the block of elements AND 60, the block of elements OR 57 the numerical value of the convolution of the message is written to the counter.

 In this case, the signal And 39 closes the signal from the decoder 59 until the conversion unit 8 performs the corresponding number of conversions. The number of conversions is taken into account by the counter 58. As soon as the counter reaches the desired value, the And 39 element opens with a signal from the decoder 59 and the clock sequence arrives at the And 43 element output. After receiving the next block by the signal from the decoder 51, the And block 56 opens through the former 53, and the constant through the block 57 of the OR elements is written to the counter 58. The And 39 element will again block the flow of clocks to the blocks 3.7 for the duration of the operation of the block 8 conversion in accordance with the constant recorded in the counter 58.

 After the conversion is completed in block 8, the decoder 59 will work, the And 39 element will open, the clock pulses will go to the message forming unit 7 and the buffer register 3. Upon completion of the input of the next block, the counter 52 will enter the state by which the decoder 51 will block the operation of the control unit 11 until the arrival of the next start signal.

 In receive mode, the switch 62 is set to position 2, while the output of signals through the element And 49 and the block 56 of the elements And is blocked. In addition, in this state of the switch 62 at the output of the block 61 adders modulo two will be the inverse value of the code received at its input. The operation of the control when receiving an informational message occurs similarly to the transfer with the only difference being that the process ends with the formation of the penultimate block.

 A device for monitoring the reliability of discrete information that implements one of the possible options for the technical use of the proposed method for monitoring the reliability of discrete information, operates as follows.

 Message Transfer Mode.

 At the “Start” signal, the control unit 11 is turned on and opens the I4 element. After that, clock pulses from the generator 5 are fed to the input of the random number generator 2, in which a chaotic sequence of bits begins to form. Clock pulses from the control unit 11 are supplied to the buffer register 3, in which the first block of the information message is written. The recording unit is set to receive information from the buffer register 3, therefore, after the reception of the information block by signals from the control unit 11, the first block of the information message through the recording unit 1 is recorded in the message generating unit 2, adding to the previous value in the adder 6 modulo two in conversion unit 8.

 Block 8 conversion generates a convolution of previous blocks of information for the first block. After the completion of the convolution, the conversion unit 8 issues a corresponding signal to the control unit 11 and the process of receiving and converting the next block of the information message is repeated. At the same time, while the block is being received in the buffer register, the previous block is recorded from the block 7 for generating the message in the register 9 of output. After receiving and converting the penultimate block of the information message, the control unit 11 closes the I4 element and the clock feed to the random number generator 2 is stopped. In addition, at this moment, the recording unit 1 is transferred to the reception mode of the information unit from the random number generator 2, and the signal from the control unit 11 records the numerical value of the generated convolution from the message generating unit 7 to the counter 58 of the control unit 11. The numerical value of the convolution of information blocks up to the last determines the number of transformations of a random number generated by this moment in the random number generator 2.

After reading the random number from the generator 2 and writing to the conversion unit 8 by the write unit 1, it is encoded into the unit 8 by performing the number of conversions equal to the numerical value of the convolution of the information message. After the coding of the last block of the information message by the signal from the control unit 11, it is written through the message generation unit 7 to the output register 9. Then the verification block is formed. To do this, the control unit 11 sets the maximum possible value of the transformations for a given convolution size (for example, if the convolution size is 32 bits, then the maximum possible value is 2 ³² -1). The random number used in the previous coding cycle is recorded in the conversion unit 8 and encoded therein by converting the set number of times. After the conversion is completed, the received test block is transferred to the output register 9 by the signal from the control unit 11. Element I10 opens and the generated informational message is issued to the output of the device.

 Message reception mode.

 When a message is received, the process of obtaining the convolution of all blocks of an informational message, up to the penultimate one, occurs in the same way as during transmission. Moreover, since the switch 62 is set in the reception mode, in order to decode the last block of information, the value of the received convolution passing through the adder block 61 is inverted, a number is added to the counter 58, which is a complement of the obtained convolution to its maximum value.

 The last block of information through block 1 of the record is fed to block 8 conversion and block 7 of the formation of the message. After that, the conversion unit 8 is turned on by the signal from the control unit 11 and the last information block is converted into the number of cycles equal to the addition of the received message convolution to its maximum value, and recorded in counter 58. As soon as the counter 58 goes to the zero state, the decoding process of the last information of the block is stopped and the received decoded information block is recorded from the conversion unit 8 through the message generation unit 7 to the output register 9. At the same time, the verification block is recorded in the buffer register 3. After the writing process of the blocks is completed, the block counter 52 switches to a state in which the operation of the I39 element is blocked from the decoder 51 and a signal is issued to enable the user to receive a message through the And 10 element.

 The issuance of a message, however, can occur only if the verification block read in the buffer register 3 matches the decoded last information block recorded in the issuing register 9. This condition is checked using the block 12 elements And, which is prepared for this test in the reception mode by a signal from switch 62.

 Further operation of the device can begin only after the start signal is issued.

 Thus, in contrast to the prototype in the proposed method, only the last information block is encoded, which gives a gain in transmission time directly proportional to the number of information blocks, which increases the speed of the method. On the other hand, the encoding operation of the last information block, which contains data known only on the transmitting side, and the operation of generating the verification block, which consists in encoding the same information block in a special way, performed on the transmitting side, and the decoding operation of the last information block, carried out as that, as a result, the numerical value of the test block is obtained, which are carried out on the receiving side, ensure the accuracy of control is the same as with Mr. method, which confirms the achievement of the objectives of the invention.

Claims (2)

 1. METHOD FOR CONTROLLING DECISIVITY OF DISCRETE INFORMATION, namely, that on the transmitting side an information message is divided into information blocks, a control convolution of previous information blocks is formed for each information block, and the control convolution of previous information blocks for the first information block of each information message is formed equal to the value known at the receiving side and the transmitted information message are supplemented with a check unit, and at the receiving side, the received information The message message is divided into information blocks, a control convolution of the previous information blocks is generated for each information block, while the control convolution value of the previous information blocks for the first information block is formed equal to the value known on the receiving side, the verification block is compared with the corresponding information block, and the results of comparison are accepted a decision on the reliability of the received information, characterized in that, in order to improve performance, on the transmitting side for the last block information form the code of the information block by its numerical value and by the control convolution of the previous information blocks, the last information block is replaced by the generated code, on the receiving side by the control convolution of the previous information blocks and the decoded information block by the numerical code value of the last information block.  2. The method according to claim 1, characterized in that on the transmitting side, as a test block, an information block code is generated, the numerical value of which is equal to the numerical value of the last decoded information block on the receiving side.

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