JP2012169964A - Algorithm variable type encryption device, algorithm variable type decryption device, algorithm variable type encryption method, algorithm variable type decryption method and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an algorithm variable type encryption device, an algorithm variable type decryption device, the method and a program, for varying an algorithm by a key while guaranteeing constant safety and processing performance.SOLUTION: The algorithm variable type encryption device comprises a round function for executing prescribed processing for two or more times, and the round function comprises a part where the algorithm varies and a part where it is fixed at all times corresponding to input key bit information.

Description

  The present invention relates to an algorithm variable encryption device, an algorithm variable decryption device, an algorithm variable encryption method, an algorithm variable decryption method, and a program that guarantee certain security and processing performance.

  In recent years, various services using computers have been provided due to the remarkable spread of the Internet. Many of the services provided in this way use encryption to conceal the communication contents. Here, as the encryption method, a common key encryption method in which encryption and decryption are performed with one key is common, but this common key encryption method is roughly divided into a block encryption method and a stream encryption method. Is done.

  An example of the stream encryption method is a non-linear function unit that inputs bit data of a random number sequence and outputs the converted bit data from a plurality of internal memories. A stream encryption apparatus comprising: an adder for adding a part of internal memory data; and a non-linear replacer for non-linear replacement of input data, wherein a plurality of internal memories are connected in a ring form through at least the non-linear replacer Has been proposed (see, for example, Patent Document 1).

JP 2006-327982 A

  In recent years, algorithmic open-type cryptographic algorithms have become mainstream, but there are also methods for keeping the algorithm secret in consideration of security. However, in the algorithm concealment type method, when reverse engineering is taken into consideration, there is a demand for an algorithm variable encryption that changes the algorithm with a key without fixing the algorithm.

  Therefore, the present invention has been made in view of the above-described problems, and an algorithm variable encryption device, an algorithm variable decryption device, and an algorithm variable that can change an algorithm with a key while guaranteeing certain safety and processing performance. It is an object to provide a type encryption method, an algorithm variable type decryption method, and a program.

  The present invention proposes the following matters in order to solve the above problems. In addition, in order to make an understanding easy, although the code | symbol corresponding to embodiment of this invention is attached | subjected and demonstrated, it is not limited to this.

  (1) The present invention is an algorithm variable type cryptographic apparatus configured by a round function that executes a predetermined process a plurality of times, wherein the round function is a portion in which the algorithm varies according to input key bit information And an algorithm variable type cryptographic apparatus characterized by comprising a fixed part at all times.

  According to the present invention, the round function is composed of a part where the algorithm is variable and a part which is always fixed in accordance with the input key bit information. Therefore, since a specific part of the algorithm can be changed by the key bit information, a certain level of security and processing performance can be guaranteed.

  (2) The present invention relates to the algorithm variable encryption device according to (1), wherein the round function replaces a data group obtained by dividing input data into predetermined bytes according to key bit information. (E.g., corresponding to the cyclic shift units 110a and 110b in FIG. 1) and exclusive OR operation means (for example, the exclusive OR calculators 120a and 120b in FIG. 1) connected to the first cyclic shift means. Corresponding to the operation determination unit 130a, 130b in FIG. 1 and the calculation result of the exclusive OR operation unit. A non-linear function unit for performing non-linear processing (for example, corresponding to the non-linear function units 140a and 140b in FIG. 1), the first cyclic shift unit, the operation determining unit, the non-linear function We propose an algorithm variable encryptor, which comprises a process executed for a predetermined number of times.

  According to the present invention, the first cyclic shift means of the round function replaces the data group obtained by dividing the input data every predetermined byte according to the key bit information. The operation determining means determines whether or not the operation is executed in the exclusive OR operation means connected to the first cyclic shift means according to the key bit information. The non-linear function unit performs non-linear processing on the operation result of the exclusive OR operation means. Then, the processing of the first cyclic shift means, the operation determination means, and the nonlinear function unit is executed a predetermined number of times. In other words, since the variable part of the algorithm is composed of the first cyclic shift means and the operation determining means that do not affect the safety and performance, even if the algorithm is varied by the above method, the safety and performance are not affected. Can be kept at a certain level.

  (3) According to the present invention, in the algorithm variable encryption device of (2), the calculation determining means (for example, corresponding to the calculation determining units 130a and 130b in FIG. 1) is 1 bit consisting of “1” or “0”. The algorithm variable type cryptographic apparatus is characterized in that execution of the operation in the exclusive OR operation means is determined based on the key bit information.

  According to this invention, the operation determining means determines the execution of the operation in the exclusive OR operation means based on 1-bit key bit information consisting of “1” or “0”. Specifically, when the key bit information is “1”, the input data is output with “1”, and when the key bit information is “0”, the input data is output with “0”. Therefore, whether or not to execute the operation in the exclusive OR operation means can be determined by 1-bit key bit information.

  (4) According to the present invention, in the algorithm variable type cryptographic apparatus of (2) or (3), the nonlinear function (for example, equivalent to the nonlinear function units 140a and 140b in FIG. 1) is composed of nonlinear substitution and linear substitution. The algorithm variable type cryptographic apparatus characterized by the above is proposed.

  According to the present invention, the nonlinear function is composed of nonlinear substitution and linear substitution.

  (5) The present invention provides the variable algorithm according to (4), wherein the nonlinear function (e.g., corresponding to the nonlinear function units 140a and 140b in FIG. 1) is an AES round function. A type encryption device is proposed.

  According to the present invention, the nonlinear function is an AES round function. That is, since the AES round function has an inverse transformation function, the decoding process can be performed by using the inverse transformation function.

  (6) The present invention relates to the algorithm variable encryption device of (1) to (5), wherein the round function performs the predetermined process until the key bit information greater than the number of bits of the input data is input. An algorithm variable type cryptographic apparatus characterized by executing is proposed.

  According to the present invention, the round function executes a predetermined process until key bit information greater than the number of bits of input data is input. That is, the security of the algorithm variable encryption device of the present invention is secured by a non-linear function, but at least by executing predetermined processing until key bit information greater than the number of bits of input data is input. Safety can be ensured without depending on the key.

  (7) The present invention is an algorithm variable decryption device configured by a round function for decrypting data encrypted in the algorithm variable encryption device according to (2), wherein the round function is encrypted. Second cyclic shift means (for example, FIG. 2) that circulates a group of data obtained by dividing the input data into predetermined bytes in a direction opposite to the first cyclic shift means in accordance with key bit information. 3 equivalent to the cyclic shift units 150a and 150b) and exclusive OR operation means connected to the second cyclic shift means (for example, equivalent to the exclusive OR calculators 120a and 120b in FIG. 3). Is determined according to the key bit information (for example, equivalent to the operation determination units 130a and 130b in FIG. 3) and the operation of the exclusive OR operation unit. And a non-linear function unit (for example, corresponding to the non-linear function units 160a and 160b in FIG. 3) that performs non-linear processing on the result using an inverse function of the non-linear function. And a variable algorithm decoding apparatus characterized by executing the processing of the nonlinear function unit a predetermined number of times.

  According to the present invention, the second cyclic shift means of the round function inputs the encrypted data, and the first cyclic circuit according to the key bit information represents a data group obtained by dividing the input data into predetermined bytes. It makes the circuit travel in the opposite direction to the shift means. The operation determining means determines whether or not the operation is executed in the exclusive OR operation means connected to the second cyclic shift means according to the key bit information. The non-linear function unit performs non-linear processing using the inverse function of the non-linear function on the operation result of the exclusive OR operation means. Then, the processing of the second cyclic shift means, the operation determination means, and the nonlinear function unit is executed a predetermined number of times. Therefore, the information encrypted in the algorithm variable encryption apparatus can be easily decrypted by setting the cyclic direction of the cyclic shift means in the reverse direction and using the inverse function of the nonlinear function.

  (8) The present invention performs algorithm variable in an algorithm variable type cryptographic apparatus that executes a predetermined process a plurality of times and includes a round function including a first cyclic shift means, an exclusive OR calculator, and a nonlinear function unit. A first encryption method, wherein the first cyclic shift means of the round function inputs data and replaces a data group obtained by dividing the input data into predetermined bytes according to key bit information. (E.g., corresponding to step S101 in FIG. 2), and whether to perform an operation in the exclusive OR calculator connected to the first cyclic shift means of the round function is determined according to the key bit information. 2 (for example, corresponding to step S102 in FIG. 2), and the nonlinear function unit performs nonlinear processing on the calculation result of the exclusive OR calculator. (For example, corresponding to step S103 in FIG. 2) and a fourth step (for example, corresponding to step S104 in FIG. 2) for executing the first to third steps a predetermined number of times. We have proposed an algorithm-variable encryption method characterized by this.

  According to the present invention, the first cyclic shift means of the round function inputs data, replaces the data group obtained by dividing the input data every predetermined byte according to the key bit information, and the first round function first The exclusive OR operator connected to the cyclic shift means determines whether or not to execute the operation according to the key bit information, and the nonlinear function unit performs nonlinear processing on the operation result of the exclusive OR operator. Do. Then, the first to third steps are executed a predetermined number of times. In other words, since the variable part of the algorithm is composed of the first cyclic shift means and the operation determining means that do not affect the safety and performance, even if the algorithm is varied by the above method, the safety and performance are not affected. Can be kept at a certain level.

  (9) The present invention decrypts the data encrypted in the algorithm variable encryption method described in (8), executes a predetermined process a plurality of times, and executes a second cyclic shift means and an exclusive OR calculator An algorithm variable decryption method in an algorithm variable decryption device configured by a round function including a non-linear function unit, wherein the second cyclic shift means of the round function inputs encrypted data, and the input A first step (for example, corresponding to step S201 in FIG. 4) of circulating a data group obtained by dividing the generated data into predetermined bytes in a direction opposite to the first cyclic shift means according to key bit information; A second step of determining whether or not to execute an operation in an exclusive OR calculator connected to the second cyclic shift means of the round function according to the key bit information ( For example, the third step (for example, corresponding to step S202 in FIG. 4) and the nonlinear function unit performs nonlinear processing on the calculation result of the exclusive OR calculator using the inverse function of the nonlinear function (for example, 4) (corresponding to step S203 in FIG. 4) and a fourth step (for example, corresponding to step S204 in FIG. 4) for executing the first to third steps a predetermined number of times. An algorithm variable decoding method is proposed.

  According to the present invention, the second cyclic shift means of the round function inputs the encrypted data, and the data group obtained by dividing the input data into predetermined bytes is converted into the first cyclic according to the key bit information. An exclusive OR calculator that determines whether or not to execute an operation in an exclusive OR calculator connected to the second cyclic shift means of the round function in a direction reverse to that of the shift means, according to the key bit information. A non-linear function unit performs non-linear processing using the inverse function of the non-linear function with respect to the calculation result. Then, the first to third steps are executed a predetermined number of times. Therefore, the information encrypted in the algorithm variable encryption apparatus can be easily decrypted by setting the cyclic direction of the cyclic shift means in the reverse direction and using the inverse function of the nonlinear function.

  (10) According to the present invention, a predetermined process is executed a plurality of times, and the algorithm variable in the algorithm variable type cryptographic apparatus configured by the round function including the first cyclic shift means, the exclusive OR calculator, and the nonlinear function unit. A program for causing a computer to execute a type encryption method, wherein the first cyclic shift means of the round function inputs data, and a group of data obtained by dividing the input data into predetermined bytes according to key bit information Key bit information indicating whether or not a first step (for example, corresponding to step S101 in FIG. 2) to be exchanged and whether or not an operation is performed in an exclusive OR calculator connected to the first cyclic shift means of the round function And a second step (for example, corresponding to step S102 in FIG. 2) determined according to the calculation result of the exclusive OR calculator The third non-linear function unit performs a non-linear process (for example, corresponding to step S103 in FIG. 2), and a fourth step (for example, the third step from the first step to the third step) (for example, 2) (corresponding to step S104 in FIG. 2).

  According to the present invention, the first cyclic shift means of the round function inputs data, replaces the data group obtained by dividing the input data every predetermined byte according to the key bit information, and the first round function first The exclusive OR operator connected to the cyclic shift means determines whether or not to execute the operation according to the key bit information, and the nonlinear function unit performs nonlinear processing on the operation result of the exclusive OR operator. Do. Then, the first to third steps are executed a predetermined number of times. In other words, since the variable part of the algorithm is composed of the first cyclic shift means and the operation determining means that do not affect the safety and performance, even if the algorithm is varied by the above method, the safety and performance are not affected. Can be kept at a certain level.

  (11) The present invention decrypts the data encrypted in the algorithm variable encryption method of (10), executes a predetermined process a plurality of times, a second cyclic shift means, an exclusive OR calculator, and a nonlinear A program for causing a computer to execute an algorithm variable decryption method in an algorithm variable decryption apparatus configured by a round function comprising a function unit, wherein the second cyclic shift means of the round function inputs encrypted data Then, a first step (for example, corresponding to step S201 in FIG. 4) is performed in which the data group obtained by dividing the input data into predetermined bytes is circulated in the opposite direction to the first cyclic shift means according to the key bit information. ) And whether or not the operation is executed in the exclusive OR calculator connected to the second cyclic shift means of the round function. The nonlinear function unit is nonlinear using an inverse function of the nonlinear function with respect to a second step (for example, corresponding to step S202 of FIG. 4) determined according to A third step for performing processing (for example, corresponding to step S203 in FIG. 4) and a fourth step for executing the predetermined number of times from the first step to the third step (for example, corresponding to step S204 in FIG. 4) ), And a program that causes a computer to execute.

  According to the present invention, the second cyclic shift means of the round function inputs the encrypted data, and the data group obtained by dividing the input data into predetermined bytes is converted into the first cyclic according to the key bit information. An exclusive OR calculator that determines whether or not to execute an operation in an exclusive OR calculator connected to the second cyclic shift means of the round function in a direction reverse to that of the shift means, according to the key bit information. A non-linear function unit performs non-linear processing using the inverse function of the non-linear function with respect to the calculation result. Then, the first to third steps are executed a predetermined number of times. Therefore, the information encrypted in the algorithm variable encryption apparatus can be easily decrypted by setting the cyclic direction of the cyclic shift means in the reverse direction and using the inverse function of the nonlinear function.

  According to the present invention, there is an effect that the algorithm can be varied by the key bit information while keeping safety and performance at a certain level.

It is a figure which shows the structure of the algorithm variable type encryption apparatus which concerns on this invention. It is a figure which shows the process of the algorithm variable type encryption apparatus which concerns on this invention. It is a figure which shows the structure of the algorithm variable type decoding apparatus which concerns on this invention. It is a figure which shows the process of the algorithm variable type decoding apparatus which concerns on this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
Note that the constituent elements in the present embodiment can be appropriately replaced with existing constituent elements and the like, and various variations including combinations with other existing constituent elements are possible. Therefore, the description of the present embodiment does not limit the contents of the invention described in the claims.

<Configuration of algorithm variable encryption device>
The configuration of the algorithm variable encryption apparatus according to the present invention will be described with reference to FIG. Note that the algorithm variable encryption device according to the present embodiment includes a round function that executes a predetermined process a plurality of times, and the algorithm varies according to the key bit information that is input to the round function. It consists of a part and a fixed part.

  The algorithm variable encryption apparatus according to the present embodiment is composed of a round function, and the details thereof are as shown in FIG. 1, cyclic shift units 110a and 110b, exclusive OR calculators 120a and 120b, and operation determination. Sections 130a and 130b and nonlinear function units 140a and 140b. In FIG. 1, an algorithm variable type encryption device that encrypts 128-bit plaintext data will be described as an example. In the present embodiment, the case where two blocks including a cyclic shift unit, an exclusive OR calculator, and a nonlinear function unit are arranged in parallel is illustrated, but the number of parallel is not limited to this, and three blocks are provided. That's all.

  Cyclic shift units 110a and 110b replace data groups obtained by dividing input data into predetermined bytes according to key bit information. Specifically, it is assumed that 128-bit input data is cyclically shifted to the right by a multiple of 4 bytes, for example. That is, it is a process of replacing the input data divided every 4 bytes according to the key bit n. For this reason, it can be mounted at high speed. At this time, since there are four shift patterns, it is possible to input a 2-bit key bit.

  The exclusive OR calculators 120a and 120b perform an exclusive OR operation on the two input data.

  The operation determination units 130a and 130b determine whether or not the exclusive OR calculators 120a and 120b connected to the cyclic shift units 110a and 110b perform the operation according to the key bit information. Specifically, it is determined whether to apply “0” or “1” to the data according to the key bit. That is, when the key bit is “0”, the bit string input to the exclusive OR calculators 120a and 120b is all “0”, so that the exclusive OR operation is not actually executed. For this process, one key bit can be input.

  The nonlinear function units 140a and 140b perform nonlinear processing on the calculation results of the exclusive OR calculators 120a and 120b. The nonlinear function units 140a and 140b are functions composed of nonlinear replacement and linear transformation. This function may be any function as long as an inverse transformation function exists, but an AES round function is preferable. Note that this function does not change regardless of the key bit.

  In the algorithm variable encryption apparatus according to the present embodiment, 2 * 2 + 1 * 2 = 6 key bits can be input in one round. Therefore, when N round processes are executed, 6N key bits can be executed. Therefore, as in this embodiment, in order to input a 128-bit key, 22 rounds are sufficient. In addition, the security of the algorithm variable encryption device according to this embodiment is essentially secured by the non-linear function units 140a and 140b. Therefore, if the number of rounds is sufficiently large, security is guaranteed regardless of the key. In addition, the algorithm variable encryption device according to the present embodiment has an advantage that a key schedule is not required.

<Processing of algorithm variable type cryptographic device>
The processing of the algorithm variable encryption device according to the present invention will be described with reference to FIG.

  First, the cyclic shift units 110a and 110b of the round function input data, and replace a data group obtained by dividing the input data into predetermined bytes according to the key bit information (step S101).

  Next, in the exclusive OR calculators 120a and 120b connected to the cyclic shift units 110a and 110b of the round function, whether or not the calculation is executed is determined according to the key bit information (step S102).

  Further, the non-linear function units 140a and 140b perform non-linear processing on the calculation results of the exclusive OR calculators 120a and 120b (step S103), and execute steps S101 to S103 a predetermined number of times (step S104). .

  Therefore, as described above, according to the present embodiment, the variable part of the algorithm is composed of the first cyclic shift unit and the operation determination unit that do not affect the safety and the performance. Even if the algorithm is changed, the safety and performance can be maintained at a certain level.

<Configuration of algorithm variable decoding device>
The configuration of the algorithm variable decoding device according to the present invention will be described with reference to FIG. The algorithm variable decryption apparatus according to the present embodiment decrypts the data encrypted by the algorithm variable encryption apparatus.

  The algorithm variable decoding device according to the present embodiment is composed of a round function. As shown in FIG. 3, the details thereof are cyclic shift units 150a and 150b, exclusive OR calculators 120a and 120b, and operation determination. Sections 130a and 130b and nonlinear function units 160a and 160b. In FIG. 3, an algorithm variable decryption device that decrypts 128-bit ciphertext data will be described as an example. In the present embodiment, the case where two blocks including a cyclic shift unit, an exclusive OR calculator, and a nonlinear function unit are arranged in parallel is illustrated, but the number of parallel is not limited to this, and three blocks are provided. That's all. In addition, components having the same reference numerals as those in the first embodiment have similar functions, and thus detailed description thereof is omitted.

  Cyclic shift units 150a and 150b receive encrypted data, and rotate a group of data obtained by dividing the input data into predetermined bytes in the reverse direction to cyclic shift units 110a and 110b according to key bit information. .

  The nonlinear function units 160a and 160b perform nonlinear processing on the calculation results of the exclusive OR calculators 120a and 120b. The non-linear function units 160a and 160b are composed of inverse transformation functions of the non-linear function units 140a and 140b.

<Processing of Algorithm Variable Decoding Device>
The processing of the algorithm variable encryption device according to the present invention will be described with reference to FIG.

  First, the round function cyclic shift units 150a and 150b receive encrypted data, and a data group obtained by dividing the input data into predetermined bytes is cyclic shift units 110a and 110b according to key bit information. The circuit is rotated in the reverse direction (step S201).

  Next, in the exclusive OR calculators 120a and 120b connected to the cyclic shift units 150a and 150b of the round function, whether or not the calculation is executed is determined according to the key bit information (step S202).

  Further, the non-linear function units 160a and 160b perform non-linear processing on the calculation results of the exclusive OR calculators 120a and 120b (step S203), and execute steps S201 to S203 a predetermined number of times (step S204). .

  Therefore, as described above, according to the present embodiment, the cyclic direction of the cyclic shift means is reversed, and the information encrypted in the algorithm variable encryption apparatus can be easily obtained by using the inverse function of the nonlinear function. Can be decrypted.

  The processing of the algorithm variable encryption device and the algorithm variable decryption device is recorded on a computer-readable recording medium, and the program recorded on the recording medium is read by the algorithm variable encryption device and the algorithm variable decryption device. By executing this, the variable algorithm type encryption device and variable algorithm type decryption device of the present invention can be realized. The computer system here includes an OS and hardware such as peripheral devices.

  Further, the “computer system” includes a homepage providing environment (or display environment) if a WWW (World Wide Web) system is used. The program may be transmitted from a computer system storing the program in a storage device or the like to another computer system via a transmission medium or by a transmission wave in the transmission medium. Here, the “transmission medium” for transmitting the program refers to a medium having a function of transmitting information, such as a network (communication network) such as the Internet or a communication line (communication line) such as a telephone line.

  The program may be for realizing a part of the functions described above. Furthermore, what can implement | achieve the function mentioned above in combination with the program already recorded on the computer system, and what is called a difference file (difference program) may be sufficient.

  The embodiments of the present invention have been described in detail with reference to the drawings. However, the specific configuration is not limited to the embodiments, and includes designs and the like that do not depart from the gist of the present invention.

110a; Cyclic shift unit 110b; Cyclic shift unit 120a; Exclusive OR operator 120b; Exclusive OR operator 130a; Operation decision unit 130b; Operation decision unit 140a; Nonlinear function unit 140b; Nonlinear function unit 150a; Unit 150b; cyclic shift unit 160a; nonlinear function unit 160b; nonlinear function unit

Claims (11)

An algorithm variable type cryptographic apparatus configured by a round function for executing a predetermined process a plurality of times,
2. The algorithm variable type cryptographic apparatus according to claim 1, wherein the round function is composed of a part where the algorithm is variable and a part which is always fixed in accordance with input key bit information. The round function is
A first cyclic shift means for replacing a data group obtained by dividing input data into predetermined bytes according to key bit information;
Calculation determining means for determining whether or not to execute an operation in the exclusive OR calculating means connected to the first cyclic shift means according to the key bit information;
A non-linear function unit that performs non-linear processing on the operation result of the exclusive OR operation means;
Consists of
2. The algorithm variable encryption apparatus according to claim 1, wherein the first cyclic shift means, the operation determination means, and the nonlinear function device are executed a predetermined number of times.   3. The algorithm variable according to claim 2, wherein the operation determining means determines the execution of the operation in the exclusive OR operation means based on 1-bit key bit information consisting of “1” or “0”. Type encryption device.   4. The algorithm variable type encryption apparatus according to claim 2, wherein the nonlinear function includes a nonlinear substitution and a linear substitution.   5. The algorithm variable type cryptographic apparatus according to claim 4, wherein the nonlinear function is an AES round function.   6. The algorithm variable encryption apparatus according to claim 1, wherein the predetermined function is executed until the round function receives the key bit information greater than or equal to the number of bits of the input data. . An algorithm variable decryption device comprising a round function for decrypting data encrypted in the algorithm variable encryption device according to claim 2,
The round function is
Second cyclic shift means for inputting encrypted data and circulating a group of data obtained by dividing the input data into predetermined bytes according to key bit information in a direction opposite to that of the first cyclic shift means; ,
Calculation determining means for determining whether or not to execute an operation in the exclusive OR calculating means connected to the second cyclic shift means according to the key bit information;
A non-linear function unit that performs non-linear processing using the inverse function of the non-linear function on the operation result of the exclusive OR operation means;
Consists of
An algorithm-variable decoding apparatus, wherein the second cyclic shift means, operation determination means, and nonlinear function device are executed a predetermined number of times. An algorithm variable encryption method in an algorithm variable encryption device configured to execute a predetermined process a plurality of times and configured by a round function including a first cyclic shift unit, an exclusive OR calculator, and a nonlinear function unit,
A first step in which a first cyclic shift means of the round function inputs data and replaces a group of data obtained by dividing the input data into predetermined bytes according to key bit information;
A second step of determining whether or not to perform an operation in accordance with key bit information in an exclusive OR calculator connected to the first cyclic shift means of the round function;
A third step in which the non-linear function unit performs non-linear processing on a calculation result of the exclusive OR calculator;
A fourth step of performing the predetermined number of times from the first step to the third step;
An algorithm variable encryption method characterized by comprising: 9. The algorithm variable encryption method according to claim 8, wherein the encrypted data is decrypted, a predetermined process is executed a plurality of times, and a second cyclic shift means, an exclusive OR calculator, and a non-linear function unit are included. An algorithm variable decoding method in an algorithm variable decoding device configured by a round function,
The second cyclic shift means of the round function inputs encrypted data, and a group of data obtained by dividing the input data into predetermined bytes is converted into the first cyclic shift means according to key bit information. A first step of cycling in the reverse direction;
A second step of determining whether or not to perform an operation in accordance with key bit information in an exclusive OR calculator connected to the second cyclic shift means of the round function;
A third step in which the nonlinear function unit performs nonlinear processing on the operation result of the exclusive OR calculator using an inverse function of the nonlinear function;
A fourth step of performing the predetermined number of times from the first step to the third step;
An algorithm variable decoding method characterized by comprising: A predetermined process is executed a plurality of times, and an algorithm variable encryption method in an algorithm variable encryption apparatus composed of a round function including a first cyclic shift means, an exclusive OR operator, and a nonlinear function unit is executed on a computer A program to
A first step in which a first cyclic shift means of the round function inputs data and replaces a group of data obtained by dividing the input data into predetermined bytes according to key bit information;
A second step of determining whether or not to perform an operation in accordance with key bit information in an exclusive OR calculator connected to the first cyclic shift means of the round function;
A third step in which the non-linear function unit performs non-linear processing on a calculation result of the exclusive OR calculator;
A fourth step of performing the predetermined number of times from the first step to the third step;
A program that causes a computer to execute. The data encrypted in the algorithm variable encryption method according to claim 10 is decrypted, a predetermined process is executed a plurality of times, and a second cyclic shift means, an exclusive OR calculator, and a non-linear function unit are included. A program for causing a computer to execute an algorithm variable decoding method in an algorithm variable decoding device configured by a round function,
The second cyclic shift means of the round function inputs encrypted data, and a group of data obtained by dividing the input data into predetermined bytes is converted into the first cyclic shift means according to key bit information. A first step of cycling in the reverse direction;
A second step of determining whether or not to perform an operation in accordance with key bit information in an exclusive OR calculator connected to the second cyclic shift means of the round function;
A third step in which the nonlinear function unit performs nonlinear processing on the operation result of the exclusive OR calculator using an inverse function of the nonlinear function;
A fourth step of performing the predetermined number of times from the first step to the third step;
A program that causes a computer to execute.

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