JP5624491B2 - Hash function device, processing method and program for hash function device - Google Patents

Description

  The present invention relates to a hash function device, a processing method of the hash function device, and a program that are safer than before.

  In recent years, various services using computers have been provided. Among them, in many services, a message authenticator is used to realize communication integrity, and a hash function algorithm is used for this message authenticator (see, for example, Non-Patent Document 1). .

FIPS PUB 180-1, SECURE HASH STANDARD, 1995, 4, 17

  However, in recent years, attacks against hash functions have been proposed and their security has been impaired. On the other hand, a new hash function with high security is also designed, but there is a problem that it takes several times as much processing time as a conventional hash function.

  Accordingly, the present invention has been made in view of the above-described problems, and an object thereof is to provide a hash function device, a hash function device processing method, and a program that realize a highly secure hash function.

  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 a hash function device in which blocks composed of a stream cipher and a hash function device are connected in multiple stages, and is a first-stage stream cipher (for example, equivalent to the stream cipher 10a in FIG. 1). Comprises a key sequence output means for outputting a key sequence, and divides the input message of the first-stage hash function unit (for example, equivalent to the hash function unit 20a in FIG. 1) by the number of stages of blocks, and A hash value for calculating a hash value by inputting the generated message data and the initial key by the message data generation means for generating message data by combining the output key sequences and the first-stage hash function unit The calculation means and the hash function units after the first stage (for example, equivalent to the hash function units 20b and 20c in FIG. 1) are generated by the preceding hash function unit. The hash value and the message data generated by the stream encryptor are input, and the calculated hash value is output to the subsequent hash function unit, which corresponds to the last hash function unit (for example, the hash function unit 20c in FIG. 1). ) Has been proposed as an output hash value.

  According to the present invention, the key sequence output means of the first-stage stream cipher outputs the key sequence. The message data generation means divides the input message of the first-stage hash function unit by the number of blocks, and generates message data by combining the output key sequence with the divided input message. The hash value calculation means of the first-stage hash function unit inputs the generated message data and the initial key and calculates a hash value. Then, the hash function unit after the first stage inputs the hash value generated by the hash function unit of the previous stage and the message data generated by the stream encryptor, and outputs the calculated hash value to the hash function unit of the subsequent stage. The hash value of the stage hash function unit is used as the output hash value. Therefore, by combining a conventional hash function and a stream cipher, it is possible to realize a high-speed hash function device while realizing high-speed processing. Further, by combining the message and the key sequence and inputting them into the hash function unit, the third party cannot estimate the algorithm, and thus the safety is improved.

  (2) The present invention proposes a hash function device in which the internal state of each stream cipher becomes a fixed value when the hash function device of (1) is used as a normal hash function. .

  According to the present invention, when used as a normal hash function, the internal state of each stream cipher becomes a fixed value. Therefore, the same hash value is output for the same message.

  (3) The present invention proposes a hash function device characterized in that when the hash function device of (1) is used as a keyed hash function, a key is input to each stream cipher.

  According to the present invention, when used as a hash function with a key, a key is input to each stream cipher. As a result, initialization processing is performed, and the same hash value is output for the same message as in a normal hash function.

  (4) In the hash function device according to (1) to (3), the present invention is characterized in that each time the stream encryptor outputs a key sequence, a different new key sequence is output. Has proposed.

  According to this invention, each time the stream cipher outputs a key sequence, it outputs a different new key sequence. Therefore, this can further increase safety.

  (5) In the hash function device according to (1) to (4), when the length of the key sequence to be input is shorter than a predetermined length, the present invention provides a fixed pattern for the amount of data that the message data generation means is insufficient. A hash function device characterized by performing the above padding processing is proposed.

  According to this invention, when the length of the input key sequence is shorter than the predetermined length, the message data generation means performs the fixed pattern padding process for the missing data. Therefore, the same hash value is output for the same message.

  (6) The present invention is a processing method of a hash function device that is formed by connecting blocks composed of a stream cipher and a hash function unit in multiple stages, and is used as a normal hash function. A first step (for example, corresponding to step S101 in FIG. 3) for outputting the key sequence, and a second step (for example, in step S101 in FIG. 3) that divides the input message of the first-stage hash function device by the number of blocks. A third step (for example, corresponding to step S101 in FIG. 3) of combining the output key sequence with the divided input message to generate message data, and the first-stage hash function unit The fourth step of inputting the generated message data and the initial key and calculating the hash value (for example, the step S101 in FIG. ) And the hash function unit after the first stage input the hash value generated by the preceding hash function unit and the message data generated by the stream encryptor, and outputs the calculated hash value to the subsequent hash function unit A fifth step (for example, corresponding to step S101 in FIG. 3) and a sixth step (for example, corresponding to step S101 in FIG. 3) using the hash value of the hash function unit at the final stage as an output hash value, The processing method of the hash function apparatus characterized by having provided is proposed.

  According to the present invention, the first-stage stream cipher outputs the key sequence and divides the input message of the first-stage hash function unit by the number of blocks. Next, the output key sequence is combined with the divided input message to generate message data, and the first-stage hash function unit calculates the hash value by inputting the generated message data and the initial key. . Then, the hash function unit after the first stage inputs the hash value generated by the hash function unit of the previous stage and the message data generated by the stream cipher, and outputs the calculated hash value to the hash function unit of the subsequent stage. The hash value of the stage hash function unit is used as the output hash value. Therefore, by combining a conventional hash function and a stream cipher, it is possible to realize a high-speed hash function device while realizing high-speed processing. Further, by combining the message and the key sequence and inputting them into the hash function unit, the third party cannot estimate the algorithm, and thus the safety is improved.

  (7) In the processing method of the hash function device according to (6), when the length of the key sequence to be input is shorter than a predetermined length, the present invention provides a fixed pattern corresponding to the missing data in the third step. The processing method of the hash function device characterized by performing the padding process is proposed.

  According to the present invention, when the length of the key sequence to be input is shorter than the predetermined length, the fixed pattern padding is performed for the insufficient data in the third step. Therefore, the same hash value is output for the same message.

  (8) The present invention is a processing method of a hash function device that is formed by connecting blocks composed of a stream cipher and a hash function unit in multiple stages, and is used as a keyed hash function. A first step (for example, corresponding to step S201 in FIG. 5) for input and initialization processing, and a second step (for example, in step S202 in FIG. 5) in which the first-stage stream cipher outputs a key sequence. Equivalent), a third step (for example, equivalent to step S203 in FIG. 5) of dividing the input message of the first-stage hash function unit by the number of stages of the block, and the output key sequence in the divided input message A fourth step (for example, equivalent to step S204 in FIG. 5) for generating message data by combining, and the first-stage hash function unit are generated A fifth step (for example, corresponding to step S205 in FIG. 5) in which the message data and the initial key are input to calculate the hash value, and the hash function unit after the first stage generates a hash value generated by the preceding hash function unit. And the message data generated by the stream cipher and a sixth step (for example, corresponding to step S206 in FIG. 5) for outputting the calculated hash value to the hash function unit in the subsequent stage, and the hash function in the final stage And a seventh step (for example, corresponding to step S207 in FIG. 5), in which a hash value of the device is used as an output hash value, has been proposed.

  According to the present invention, a key is input to each stream cipher, initialization processing is performed, the first-stage stream cipher outputs a key sequence, and the input message of the first-stage hash function unit is divided by the number of blocks. . Next, the key sequence output to the divided input message is combined to generate message data, and the hash function unit in the first stage inputs the generated message data and the initial key to calculate a hash value. Then, the hash function unit after the first stage inputs the hash value generated by the hash function unit of the previous stage and the message data generated by the stream cipher, and outputs the calculated hash value to the hash function unit of the subsequent stage. The hash value of the stage hash function unit is used as the output hash value. Therefore, by combining a conventional hash function and a stream cipher, it is possible to realize a high-speed hash function device while realizing high-speed processing. Further, by combining the message and the key sequence and inputting them into the hash function unit, the third party cannot estimate the algorithm, and thus the safety is improved.

  (9) In the processing method of the hash function device according to (8), when the length of the input key sequence is shorter than a predetermined length, the present invention provides a fixed pattern corresponding to the deficient data in the fourth step. The processing method of the hash function device characterized by performing the padding process is proposed.

  According to the present invention, when the length of the input key sequence is shorter than the predetermined length, in the fourth step, the fixed pattern padding is performed for the missing data. Therefore, the same hash value is output for the same message.

  (10) The present invention is a program for causing a computer to execute a processing method of a hash function device that is formed by connecting blocks composed of a stream encryption device and a hash function device in multiple stages and used as a normal hash function. The first-stage stream cipher outputs a first step (for example, corresponding to step S101 in FIG. 3), and a second step of dividing the input message of the first-stage hash function unit by the number of block stages ( For example, this corresponds to step S101 in FIG. 3), and a third step (for example, corresponding to step S101 in FIG. 3) for generating message data by combining the output key sequence with the divided input message. The first-stage hash function unit calculates a hash value by inputting the generated message data and an initial key. Step (for example, corresponding to step S101 in FIG. 3), and the hash function unit after the first stage input the hash value generated by the hash function unit of the previous stage and the message data generated by the stream cipher, and operated A fifth step (for example, corresponding to step S101 in FIG. 3) for outputting the hash value to the subsequent hash function device, and a sixth step (for example, for example) using the hash value of the last hash function device as the output hash value 3) (corresponding to step S101 in FIG. 3).

  According to the present invention, the first-stage stream cipher outputs the key sequence and divides the input message of the first-stage hash function unit by the number of blocks. Next, the output key sequence is combined with the divided input message to generate message data, and the first-stage hash function unit calculates the hash value by inputting the generated message data and the initial key. . Then, the hash function unit after the first stage inputs the hash value generated by the hash function unit of the previous stage and the message data generated by the stream cipher, and outputs the calculated hash value to the hash function unit of the subsequent stage. The hash value of the stage hash function unit is used as the output hash value. Therefore, by combining a conventional hash function and a stream cipher, it is possible to realize a high-speed hash function device while realizing high-speed processing. Further, by combining the message and the key sequence and inputting them into the hash function unit, the third party cannot estimate the algorithm, and thus the safety is improved.

  (11) The present invention is a program for causing a computer to execute a processing method of a hash function device used as a keyed hash function by connecting blocks composed of a stream cipher and a hash function unit in multiple stages. , A first step (for example, corresponding to step S201 in FIG. 5) for inputting a key to each stream cipher and performing an initialization process, and a second step in which the first-stage stream cipher outputs a key sequence ( For example, corresponding to step S202 in FIG. 5), a third step (for example, corresponding to step S203 in FIG. 5) for dividing the input message of the first-stage hash function device by the number of stages of the block, and the divided input message A fourth step (for example, corresponding to step S204 in FIG. 5) for generating message data by combining the output key sequence with A fifth step (for example, corresponding to step S205 of FIG. 5) in which the first-stage hash function unit inputs the generated message data and an initial key to calculate a hash value; A sixth step (for example, FIG. 5) in which the hash value generated by the preceding hash function unit and the message data generated by the stream encryptor are input and the calculated hash value is output to the subsequent hash function unit. And a seventh step (for example, corresponding to step S207 in FIG. 5) that uses the hash value of the hash function unit at the final stage as an output hash value is proposed. doing.

  According to the present invention, a key is input to each stream cipher, initialization processing is performed, the first-stage stream cipher outputs a key sequence, and the input message of the first-stage hash function unit is divided by the number of blocks. . Next, the key sequence output to the divided input message is combined to generate message data, and the hash function unit in the first stage inputs the generated message data and the initial key to calculate a hash value. Then, the hash function unit after the first stage inputs the hash value generated by the hash function unit of the previous stage and the message data generated by the stream cipher, and outputs the calculated hash value to the hash function unit of the subsequent stage. The hash value of the stage hash function unit is used as the output hash value. Therefore, by combining a conventional hash function and a stream cipher, it is possible to realize a high-speed hash function device while realizing high-speed processing. Further, by combining the message and the key sequence and inputting them into the hash function unit, the third party cannot estimate the algorithm, and thus the safety is improved.

  According to the present invention, by combining a conventional hash function and a stream cipher, it is possible to realize high-speed processing and to realize a highly secure hash function device.

It is a figure which shows the structure of the hash function apparatus which concerns on the 1st Embodiment of this invention. It is a figure explaining the production | generation of the input message data in the hash function apparatus which concerns on the 1st Embodiment of this invention. It is a figure which shows the processing flow of the hash function apparatus which concerns on the 1st Embodiment of this invention. It is a figure which shows the structure of the hash function apparatus which concerns on the 2nd Embodiment of this invention. It is a figure which shows the processing flow of the hash function apparatus which concerns on the 2nd Embodiment of 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.
<First Embodiment>

  A first embodiment of the present invention will be described with reference to FIGS.

  As shown in FIG. 1, the hash function device according to this embodiment is configured by combining functional blocks including a stream encryption device 10a and the like and a hash function device 20a and the like in multiple stages. In this embodiment, a hash function device is shown in which the functional blocks are combined in three stages. However, the number of blocks to be combined is not limited to this.

  First, in the first-stage functional block, a key sequence generated by the stream cipher 10a is concatenated with a message obtained by dividing a normal message according to the number of stages to constitute an input message. Here, as shown in FIG. 2, when the data length obtained by concatenating the divided message and the key sequence is shorter than the predetermined data length, a fixed pattern (“X ·· X” in FIG. 2) is used. To perform padding processing. The above processing is the same for the functional blocks in the subsequent stages.

  The stream cipher 10a is updated each time a key sequence is output, and outputs a different key sequence. Further, when used as a normal hash function as in the present embodiment, the internal state of the stream cipher 10a is a fixed value. The same applies to the stream ciphers 10b and 10c in the subsequent stages.

  The hash function unit 20a inputs the above-mentioned input message and the initial value IV and outputs a hash value. The output hash value is input to the next hash function unit 20b.

  In the next functional block, an input message is formed by concatenating a key sequence generated by the stream encryptor 10b to a message obtained by dividing a normal message according to the number of stages. The hash function unit 20b inputs the above-mentioned input message and the hash value input from the hash function unit 20a, and outputs a hash value. The output hash value is input to the next hash function unit 20c.

  In the last-stage functional block, a key sequence generated by the stream cipher 10c is connected to a message obtained by dividing a normal message according to the number of stages to constitute an input message. The hash function unit 20c inputs the above-described input message and the hash value input from the hash function unit 20b, and outputs a hash value. This hash value becomes the output value of the hash function device.

<Hash function device processing>
The process of the hash function device according to this embodiment will be described with reference to FIG.

  First, the first-stage stream cipher 10a outputs a key sequence (step S101), and divides the input message of the first-stage hash function unit 20a by the number of blocks (step S102).

  The key sequence output to the divided input message is combined to generate message data (step S103), and the first-stage hash function unit 20a calculates the hash value by inputting the generated message data and the initial key. (Step S104).

Then, the hash function units 20b and 20c after the first stage input the hash value generated by the preceding hash function unit 20a, the message data obtained by combining the key sequence generated by the stream cipher and the divided message, and the calculation The hash value thus obtained is output to the subsequent hash function unit (step S105), and the hash value of the last hash function unit 20c is set as the output hash value (step S106).

As described above, according to the present embodiment, by combining a conventional hash function and a stream cipher, it is possible to realize a high-speed hash function device while realizing high-speed processing. Further, by combining the message and the key sequence and inputting them into the hash function unit, the third party cannot estimate the algorithm, and thus the safety is improved.
<Second Embodiment>

  A second embodiment of the present invention will be described with reference to FIGS.

  The basic configuration of the hash function device of the present embodiment is the same as that of the first embodiment, but in this embodiment, the case where the hash function device is used as a keyed hash function is shown. Therefore, detailed description of the same parts as those of the first embodiment is omitted.

  The stream ciphers 11a to 11c according to the present embodiment perform initialization processing before inputting a key from outside and generating a key sequence. Other operations are the same as those in the first embodiment.

<Hash function device processing>
The process of the hash function device according to this embodiment will be described with reference to FIG.

  First, a key is input to each of the stream ciphers 11a, 11b, and 11c, and an initialization process is performed (step S201). Next, the first-stage stream cipher 11a outputs a key sequence (step S202), and divides the input message of the first-stage hash function unit 20b by the number of blocks (step S203).

  The key sequence output to the divided input message is combined to generate message data (step S204), and the first-stage hash function unit 20a calculates the hash value by inputting the generated message data and the initial key. (Step S205).

Then, the hash function units 20b and 20c after the first stage input the hash value generated by the preceding hash function unit 20a, the message data obtained by combining the key sequence generated by the stream cipher and the divided message, and the calculation The hash value thus obtained is output to the hash function unit at the subsequent stage (step S206), and the hash value of the hash function unit 20c at the final stage is set as the output hash value (step S207).

  As described above, according to the present embodiment, by combining a conventional hash function and a stream cipher, it is possible to realize a high-speed hash function device while realizing high-speed processing. Further, by combining the message and the key sequence and inputting them into the hash function unit, the third party cannot estimate the algorithm, and thus the safety is improved.

  The hash function device of the present invention can be realized by recording the processing of the hash function device on a computer-readable recording medium, causing the hash function device to read and execute the program recorded on the recording medium. . 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.

10a; stream cipher 10b; stream cipher 10c; stream cipher 11a; stream cipher 11b; stream cipher 11c; stream cipher 20a; hash function unit 20b; hash function unit 20c;

Claims (11)

A hash function device formed by connecting blocks composed of a stream cipher and a hash function device in multiple stages,
A first-stage stream cipher, key sequence output means for outputting a key sequence ;
Message data generating means for dividing an input message by the number of stages of blocks, and combining the output key sequence with the divided input message to generate message data;
The first-stage hash function unit, the hash value calculating means for calculating the hash value by inputting the generated message data and the initial key (IV) ;
With
The hash function unit after the first stage inputs the hash value generated by the hash function unit of the previous stage, the message data obtained by combining the key sequence generated by the stream cipher and the divided input message, and the calculated hash value Is output to the hash function unit at the subsequent stage, and the hash value of the hash function unit at the final stage is used as the output hash value.   2. The hash function device according to claim 1, wherein when used as a normal hash function, the internal state of each stream cipher becomes a fixed value.   2. The hash function device according to claim 1, wherein a key is input to each stream cipher when used as a hash function with a key.   4. The hash function device according to claim 1, wherein each time the stream cipher outputs a key sequence, a different new key sequence is output. 5.   5. The fixed pattern padding process is performed for the data that the message data generation unit lacks when the length of the input key sequence is shorter than a predetermined length. Hash function device. A processing method of a hash function device, which is formed by connecting blocks composed of a stream cipher and a hash function device in multiple stages, and used as a normal hash function,
A first step in which a first-stage stream cipher outputs a key sequence;
A second step of dividing the input message by the number of stages of blocks;
A third step of generating message data by combining the output key sequence with the divided input message;
A fourth step in which the first-stage hash function unit inputs the generated message data and an initial key (IV) to calculate a hash value;
The hash function unit after the first stage inputs the hash value generated by the hash function unit of the previous stage, the message data obtained by combining the key sequence generated by the stream cipher and the divided input message, and the calculated hash value Is output to the hash function unit in the subsequent stage, and
A sixth step in which the hash value of the hash function unit at the final stage is set as the output hash value;
A processing method for a hash function device, comprising:   7. The hash function device according to claim 6, wherein when the length of the input key sequence is shorter than a predetermined length, padding processing of a fixed pattern is performed for the missing data in the third step. Processing method. A processing method of a hash function device, which is formed by connecting blocks composed of a stream cipher and a hash function device in multiple stages and used as a keyed hash function,
A first step of inputting a key into each stream cipher and performing an initialization process;
A first step in which a first-stage stream cipher outputs a key sequence;
A third step of dividing the input message by the number of stages of blocks;
A fourth step of generating message data by combining the output key sequence with the divided input message;
A first step in which the first-stage hash function unit inputs the generated message data and the initial key (IV) to calculate a hash value;
The hash function unit after the first stage inputs the hash value generated by the hash function unit of the previous stage, the message data obtained by combining the key sequence generated by the stream cipher and the divided input message, and the calculated hash value A sixth step of outputting to a hash function unit in the subsequent stage;
A seventh step in which the hash value of the hash function unit at the final stage is set as the output hash value;
A processing method for a hash function device, comprising:   9. The hash function device according to claim 8, wherein when the length of the input key sequence is shorter than a predetermined length, padding processing of a fixed pattern is performed for the missing data in the fourth step. Processing method. A program for connecting a block consisting of a stream cipher and a hash function unit in multiple stages and causing a computer to execute a processing method of a hash function device used as a normal hash function,
A first step in which a first-stage stream cipher outputs a key sequence;
A second step of dividing the input message by the number of stages of blocks;
A third step of generating message data by combining the output key sequence with the divided input message;
A fourth step in which the first-stage hash function unit inputs the generated message data and an initial key (IV) to calculate a hash value;
The hash function unit after the first stage inputs the hash value generated by the hash function unit of the previous stage, the message data obtained by combining the key sequence generated by the stream cipher and the divided input message, and the calculated hash value Is output to the hash function unit in the subsequent stage, and
A sixth step in which the hash value of the hash function unit at the final stage is set as the output hash value;
A program that causes a computer to execute. A program for connecting a block consisting of a stream cipher and a hash function unit in multiple stages and causing a computer to execute a processing method of a hash function device used as a keyed hash function,
A first step of inputting a key into each stream cipher and performing an initialization process;
A first step in which a first-stage stream cipher outputs a key sequence;
A third step of dividing the input message by the number of stages of blocks;
A fourth step of generating message data by combining the output key sequence with the divided input message;
A first step in which the first-stage hash function unit inputs the generated message data and the initial key (IV) to calculate a hash value;
The hash function unit after the first stage inputs the hash value generated by the hash function unit of the previous stage, the message data obtained by combining the key sequence generated by the stream cipher and the divided input message, and the calculated hash value A sixth step of outputting to a hash function unit in the subsequent stage;
A seventh step in which the hash value of the hash function unit at the final stage is set as the output hash value;
A program that causes a computer to execute.

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