JP2013157777A - Information processing system and information processing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a system and method in which alteration of data and authenticity of a transmission source can be verified.SOLUTION: A data generation part 4 of a sender side device 1 generates data D, a secret information generation part 5 generates secret information S1. A data processing part 6 adds the secret information S1 to the data D immediately after the generation to convert the secret information S1 into a hash value H1 with a hash function. A key generation storage part 7 generates a pair of a secret key and a public key. An encryption part 8 encrypts the hash value H1 with the secret key to acquire a signature value S. An output part 9 outputs the data D and the signature value S, and an input part 10 of a receiver side device 2 inputs them. A secret information generation part 11 generates same secret information S2 as the secret information S1. A data processing part 12 converts data in which the secret information S2 is added to the data D into a hash value H2 with the hash function. A decryption part 13 decrypts the signature value S with the public key to acquire a hash value H3. A verification part 14 verifies whether or not the hash value H2 and the hash value H3 are the same.

Description

  The present invention relates to an information processing system and an information processing method using a public key cryptosystem, and more particularly to an information processing system and an information processing method capable of verifying data tampering and authenticity of a transmission source.

  In recent years, terminal devices such as smartphones and tablets that can acquire information such as time and position and can easily acquire or create photos, sounds, documents, and the like as data have become widespread. Data obtained by adding information such as time and position as attribute values to data created by these terminal devices is effective as various proofs. However, it is necessary to confirm whether the transmission source of the transmitted data is correct or whether it has been altered on the transmission line. Therefore, it has been proposed to apply an electronic signature (see, for example, Patent Documents 1 and 2).

JP 2010-87702 A Japanese Patent No. 4543570

  In the prior art, if data has been falsified before the electronic signature is applied, the falsification cannot be found. In addition, when a falsifier steals a secret key and transmits data by pretending to be a sender, it cannot be found that the data transmission source is incorrect.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to obtain an information processing system and an information processing method that can verify data falsification and authenticity of a transmission source.

  An information processing system according to the present invention includes a sender-side device and a receiver-side device, and the sender-side device includes a data generation unit that generates data and first secret information that generates first secret information. A generating unit, a first data processing unit that adds the first secret information to the data immediately after the data is generated, and converts the first secret information into a first hash value by a hash function, and a public key cryptosystem A key generation / storage unit that generates a private key / public key pair used for the electronic signature and stores the private key; and an encryption unit that encrypts the first hash value with the private key to obtain a signature value; A first output unit that outputs the data and the signature value, and the receiver side device includes a first input unit that inputs the data and the signature value output by the sender side device; , Generating the same second secret information as the first secret information A second secret information generation unit that converts the data to which the second secret information is added into a second hash value by the hash function, and discloses the signature value to the public A first decryption unit that obtains a third hash value by decrypting with a key, and a first verification unit that verifies whether the second hash value and the third hash value are the same. And

  According to the present invention, it is possible to verify data falsification and authenticity of a transmission source.

It is a figure which shows the information processing system which concerns on Embodiment 1 of this invention. It is a figure which shows the information processing system which concerns on a comparative example. It is a figure which shows the information processing system which concerns on Embodiment 2 of this invention.

  An information processing system and an information processing method according to an embodiment of the present invention will be described with reference to the drawings. The same or corresponding components are denoted by the same reference numerals, and repeated description may be omitted.

Embodiment 1 FIG.
FIG. 1 is a diagram showing an information processing system according to Embodiment 1 of the present invention. This system is a digital signature system using a public key cryptosystem, and includes a sender apparatus 1, a receiver apparatus 2, and a certification authority 3 (CA: Certification Authority).

  The sender-side device 1 includes a data generation unit 4, a secret information generation unit 5, a data processing unit 6, a key generation storage unit 7, an encryption unit 8, and an output unit 9. The receiver-side device 2 includes an input unit 10, a secret information generation unit 11, a data processing unit 12, a decryption unit 13, and a verification unit 14.

  The data generation unit 4 and the secret information generation units 5 and 11 are dedicated programs. The secret information generation units 5 and 11 are programs having the same contents installed in the sender side device 1 and the receiver side device 2 in a secure manner, respectively. The secret information generation units 5 and 11, the key generation storage unit 7, and the encryption unit 8 are provided in the sender-side device 1 or a tamper-resistant device (such as an IC card) attached to the sender-side device 1. It may be.

  Next, the operation of the system according to the present embodiment will be described. First, the key generation / storage unit 7 generates a private key / public key pair to be used for an electronic signature of the public key cryptosystem. When sending the public key to the certificate authority 3, in order to prevent key spoofing, the sender's public key and identification information are signed with the sender's private key. Identification information is information that can identify an individual such as name, affiliation, e-mail address, employee (student) number, etc., and usually a combination of multiple types of information is used. The certificate authority 3 verifies the signature information transmitted from the sender, and signs the public key and the identification information, thereby generating the sender's public key certificate. The private key generated by the key generation / storage unit 7 and the public key certificate returned from the certificate authority 3 are stored in the key generation / storage unit 7. When the sender sends the public key certificate to the receiver, or when the receiver accesses a server (repository) linked to the certificate authority 3, the receiver-side apparatus 2 receives the sender's public key certificate. Get information.

  Next, in the sender apparatus 1, the data generation unit 4 generates data D, and the secret information generation unit 5 generates secret information S1. The data D includes electronic data (photographed photograph, recorded voice, created document, etc.) and attribute information (sender information, location information, time information, etc.). The secret information S1 is generated by a method known only to a specific manager in the group, such as a fixed value, a value based on a specific rule, and a random number.

  Next, the data processing unit 6 adds the secret information S1 to the data D, and converts it into a hash value H1 using a hash function. This data processing needs to be performed immediately after the data D and the secret information S1 are generated in order to avoid the risk of falsification of the data D as much as possible. Next, the encryption unit 8 encrypts the hash value H1 with a secret key to obtain a signature value S.

  Next, the output unit 9 of the sender apparatus 1 outputs the data D and the signature value S. The data D and the signature value S are input by the input unit 10 of the receiver side device 2. Specifically, the data D and the signature value S are transmitted from the sender-side device 1 to the receiver-side device 2 through a secure network (transmission line) such as a dedicated line. However, the output unit 9 of the sender-side device 1 stores the data D and the signature value S in the portable storage medium 15 (SD card, USB memory, etc.), and the portable storage medium 15 is handed over from the sender to the receiver. The input unit 10 of the recipient apparatus 2 may read the data D and the signature value S from the portable storage medium 15. The signature value S is stored in one of the attribute information fields of the data D. It is assumed that the private key is not duplicated and is held only by the creator. When the data D is transferred from the sender to the receiver, the secret information is not included in the data D.

  Next, the secret information generation unit 11 generates the same secret information S2 as the secret information S1. Then, the data processing unit 12 converts the data D added with the secret information S2 into a hash value H2 using the same hash function as that used by the sender apparatus 1. On the other hand, the decryption unit 13 decrypts the signature value S with the public key obtained in advance to obtain the hash value H3.

  Finally, the verification unit 14 verifies whether the hash value H2 and the hash value H3 are the same. If both are the same, it can be determined that the data D has not been tampered with. On the other hand, if the data D has been tampered with, the hash value H2 and the hash value H3 are different even if the same hash function is used.

  Subsequently, the effect of the present embodiment will be described in comparison with a comparative example. FIG. 2 is a diagram illustrating an information processing system according to a comparative example. In the comparative example, the secret information generation units 5 and 11 do not exist. The data processing unit 6 converts only the data D into a hash value H1 ′ using a hash function.

  In the comparative example, if the data is falsified before the electronic signature is applied, the falsification cannot be found. On the other hand, in the present embodiment, the secret information S1 is added to the data D immediately after the data D is generated, and it is converted into a hash value H1 by a hash function. For this reason, it is possible to detect alteration of data before applying the electronic signature.

  Further, in the comparative example, when the falsifier steals the secret key and impersonates the sender and transmits data, it cannot be found that the data transmission source is not the sender apparatus 1. On the other hand, in this embodiment, since the secret information is not added to the data transmitted by the tamper, the receiver side device 2 can discover that the data transmission source is not the sender side device 1. . Thereby, the receiver side apparatus 2 can verify the authenticity of the data transmission source.

Embodiment 2. FIG.
FIG. 3 is a diagram showing an information processing system according to Embodiment 2 of the present invention. This system further includes a third-party device 16 in addition to the configuration of the first embodiment. Here, the third party is a person who wants to verify the authenticity of data other than the sender and the receiver. For example, in the exchange of data between contractors in the construction work, the orderer of the construction work corresponds to a third party.

  In addition, the receiver-side device 2 further includes an output unit 17 that outputs the data D and the signature value S when the hash value H2 and the hash value H3 are the same. The third party apparatus 16 includes an input unit 18, a secret information generation unit 19, a data processing unit 20, a decryption unit 21, and a verification unit 22.

  Next, the operation of the system according to the present embodiment will be described. First, the operation of the first embodiment is performed, and when the hash value H2 and the hash value H3 are the same as the verification result, the output unit 17 of the receiver apparatus 2 outputs the data D and the signature value S. Then, the input unit 18 of the third party device 16 inputs the data D and the signature value S output from the receiver device 2. Next, the secret information generation unit 19 generates the same secret information S3 as the secret information S1.

  Next, the data processing unit 20 converts the data D added with the secret information S3 into a hash value H4 using a hash function. On the other hand, the decryption unit 21 decrypts the signature value S with the public key obtained in advance to obtain the hash value H5. Next, the verification unit 22 verifies whether the hash value H4 and the hash value H5 are the same. If both are the same, it can be determined that the data has not been tampered with. On the other hand, if the data D has been tampered with, the hash value H4 and the hash value H5 are different even if the same hash function is used. Thereby, the third party apparatus 16 can verify the authenticity of the data D.

  Further, since the secret information is not added to the data transmitted by the tamper, the third party device 16 can discover that the data transmission source is not the receiver device 2. That is, the third party device 16 can verify the authenticity of the data transmission source.

DESCRIPTION OF SYMBOLS 1 Transmitter side apparatus 2 Receiver side apparatus 4 Data generation part 5 Secret information generation part (1st secret information generation part)
6 Data processing unit (first data processing unit)
7 Key generation storage unit 8 Encryption unit 9 Output unit (first output unit)
10 Input section (first input section)
11 Secret information generation unit (second secret information generation unit)
12 Data processing unit (second data processing unit)
13 Decoding unit (first decoding unit)
14 Verification unit (first verification unit)
15 Portable storage medium 16 Third-party device 17 Output unit (second output unit)
18 Input unit (second input unit)
19 Secret information generator (third secret information generator)
20 Data processing unit (third data processing unit)
21 Decoding unit (second decoding unit)
22 Verification unit (second verification unit)

Claims (6)

A sender-side device and a receiver-side device,
The sender device is
A data generation unit for generating data;
A first secret information generation unit for generating first secret information;
A first data processing unit that adds the first secret information to the data immediately after the data is generated, and converts the first secret information into a first hash value by a hash function;
A key generation storage unit that generates a pair of a private key and a public key used for an electronic signature of a public key cryptosystem, and stores the private key;
An encryption unit that encrypts the first hash value with the secret key to obtain a signature value;
A first output unit for outputting the data and the signature value;
The receiver side device
A first input unit for inputting the data and the signature value output by the sender side device;
A second secret information generating unit that generates the same second secret information as the first secret information;
A second data processing unit for converting the data added with the second secret information into a second hash value by the hash function;
A first decryption unit that decrypts the signature value with the public key to obtain a third hash value;
An information processing system comprising: a first verification unit that verifies whether the second hash value and the third hash value are the same. A third-party device,
The receiver apparatus further includes a second output unit that outputs the data and the signature value when the second hash value and the third hash value are the same,
The third party device is
A second input unit for inputting the data and the signature value output by the receiver side device;
A third secret information generation unit that generates the same third secret information as the first secret information;
A third data processing unit that converts the data added with the third secret information into a fourth hash value by the hash function;
A second decryption unit for decrypting the signature value with the public key to obtain a fifth hash value;
The information processing system according to claim 1, further comprising: a second verification unit that verifies whether the fourth hash value is the same as the fifth hash value. The first output unit stores the data and the signature value in a portable storage medium;
The information processing system according to claim 1, wherein the first input unit reads the data and the signature value from the portable storage medium.   The first secret information generation unit, the second secret information generation unit, the key generation storage unit, and the encryption unit are provided in a tamper-resistant device. The information processing system according to any one of the above. A step of generating data by the data generation unit of the sender side device;
A step of generating a first secret information by a first secret information generation unit of the sender device;
A step in which the first data processing unit of the sender-side apparatus adds the first secret information to the data immediately after the data is generated, and converts the first secret information into a first hash value by a hash function; ,
A step of generating a private key and public key pair for use in an electronic signature of a public key cryptosystem, and storing the private key, wherein the key generation and storage unit of the sender side device;
An encryption unit of the sender device encrypts the first hash value with the secret key to obtain a signature value;
A first output unit of the sender device outputting the data and the signature value;
A first input unit of a receiver side device inputting the data and the signature value output by the sender side device;
A second secret information generation unit of the receiver-side device generates second secret information that is the same as the first secret information;
A step in which a second data processing unit of the receiver side device converts the data added with the second secret information to a second hash value by the hash function;
A first decryption unit of the receiver-side device decrypts the signature value with the public key to obtain a third hash value;
An information processing method comprising: a step of verifying whether or not the second hash value and the third hash value are the same by a first verification unit of the receiver side device. A step of outputting the data and the signature value when the second output unit of the receiver-side device has the same second hash value and the third hash value;
A second input unit of the third party side device inputs the data and the signature value output by the receiver side device;
A third secret information generating unit of the third party side device generating third secret information that is the same as the first secret information;
A step in which a third data processing unit of the third-party device converts the data added with the third secret information to a fourth hash value by the hash function;
A second decryption unit of the third-party device decrypts the signature value with the public key to obtain a fifth hash value;
The second verification unit of the third-party device further includes a step of verifying whether the fourth hash value and the fifth hash value are the same. Information processing method.

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