JP2002258745A - Digital signature device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To electronically sign only data which a signer has surely confirmed. SOLUTION: A CPU 14 receives data of a check or the like, which should be electronically signed, through a USB cable 10 and supplies this document data to a liquid crystal monitor 8 to display a picture of the check. The signer puts his or her finger on a fingerprint collation sensor 6 after seeing this display to confirm contents. The fingerprint collation sensor 6 reads the fingerprint to generate its video signal, and a fingerprint collation circuit 18 identifies the signer on the basis of the fingerprint picture represented by this video signal. Then, the CPU 14 starts a cipher processing circuit 20 to supply the document data to the cipher processing circuit 20. The cipher processing circuit 20 generates hash values of the document data and uses a secret key out of a public key and the secret key, which have been preliminarily generated on the basis of a public cipher key system, to encipher the hash values. The CPU 14 outputs the result through the USB cable 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic signature device.

[0002]

2. Description of the Related Art In recent years, electronic payment through a communication network has been widely used as a technique for proving that a document or the like has been created by a person who signed the document and has not been tampered with by others. The importance is increasing together with the above. FIG. 5 is a configuration diagram showing an example of such a conventional digital signature device. Digital signature device 10 shown in FIG.
2 is a fingerprint collator 104 (Japanese Patent Laid-Open No. 2000-188594).
Publication) and personal computer 106 (personal computer 1)
06). When performing an electronic signature, the signer first operates the personal computer 106 to display an image of the check 108 on the screen of the personal computer 106 based on the data of the check 108 to be electronically signed, for example. The signer sees this and checks the contents of the check 108, and if there is no mistake, the fingerprint collator 10
The user places his / her finger 111 on the fingerprint collation sensor 110. Accordingly, the fingerprint collator 104 reads the fingerprint to generate fingerprint image data, compares it with the signer's fingerprint image data registered in advance in the fingerprint collator 104, and registers the read fingerprint. It is determined whether the fingerprint is present.

If the result of this determination is positive, the fingerprint collator 104 converts the secret key among the public key and secret key generated in advance based on the public encryption key method into the cable 1.
12 to the personal computer 106. PC 10
When the secret key is received from the fingerprint collator 104, the hash value is generated on the side of the fingerprint collator 104 based on the data of the check 108, and the hash value is used as the fingerprint collator 1
Encrypt using the secret key from 04. The hash value may be encrypted by the fingerprint collator 104. In this case, the personal computer 106 sends the generated hash value to the fingerprint collator 104, and the fingerprint collator 104 transmits the hash value from the personal computer to the secret data. Encrypted with a key and personal computer 1
06 is output.

[0004] Thus, the digital signature is completed, and the encrypted hash value is passed to the recipient through a communication network or a storage medium. On the side receiving the hash value, the hash value is decrypted using the signer's public key, and the hash value of the check 108 is generated by the same algorithm as that of the personal computer 106. If the generated hash value matches the decrypted hash value, it can be determined that the check 108 has definitely been signed by the signer.

[0005]

However, such a digital signature device 102 is desired to be improved in the following points in order to further enhance security. That is, the personal computer 1
For example, when 06 is connected to a communication network, the program may be incorporated in the personal computer 106 through the communication network in some form. The program then checks 108 as described above.
It is possible that the amount of the check 108 is changed from 1,000,000 yen to 1.2 million yen at the stage of generating the hash value from.

[0006] When such a change is made, the signer puts a check 108 describing 1 million yen on the personal computer 106.
Despite confirming and signing on the screen of
Signing a check of 10,000 yen would result in loss. The present invention has been made to solve this kind of problem, and an object of the present invention is to provide an electronic signature device that ensures that an electronic signature is performed only on data confirmed by a signer. is there.

[0007]

In order to achieve the above object, the present invention represents an authentication means for determining whether a signer is a specific person registered in advance, and data to be digitally signed. Information output means for outputting information; hash value generation means for generating a hash value from data to be subjected to the electronic signature; encryption key generation means for generating a public key and a secret key based on a public key cryptosystem; A hash value encryption unit that encrypts the hash value generated by the hash value generation unit using the secret key generated by the key generation unit; and verifies that the signer is a registered specific person. A hash value output unit that outputs the hash value encrypted by the hash value encryption unit when the unit determines.

In the electronic signature device of the present invention, the information output means outputs information representing data to be subjected to an electronic signature, and the signer confirms the contents of the data to be electronically signed based on the output result. be able to. Then, the hash value generation means generates a hash value based on the data to be digitally signed. Thereafter, the hash value encryption unit encrypts the hash value generated by the hash value generation unit using the secret key generated by the encryption key generation unit, and the hash value output unit authenticates that the signer is a specific person. When the means determines, the hash value encrypted by the hash value encryption means is output. As described above, in the present invention, the data from which the information output means outputs information for content confirmation and the data used by the hash value generation means for generating the hash value are always the same, and therefore, the signer must always confirm the data. An electronic signature is performed only on data.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an example of an electronic signature device according to the present invention, FIG. 2A is an external view showing the electronic signature device, and FIG. 1B is a plan view showing an example of a document displayed on a liquid crystal monitor. . As shown in FIG. 2A, the electronic signature device 2 of the present embodiment has a fingerprint matching sensor 6 and a liquid crystal monitor 8 ( LCD monitor). Fingerprint collation sensor 6
Reads a fingerprint from a finger 28 disposed on the fingerprint collation sensor 6 and generates a video signal of the fingerprint. The liquid crystal monitor 8 is provided for displaying an image of a document based on data of the document to be digitally signed, which is supplied through the USB cable 10.

More specifically, the electronic signature device 2 has a configuration as shown in FIG. That is, the electronic signature device 2 includes a CPU 14 and a program memory 16 connected by the bus line 12, and the CPU 14 operates based on the program data stored in the program memory 16 and controls the entire electronic signature device 2.

The bus line 12 also has a fingerprint matching circuit 1
8 and the cryptographic processing circuit 20 are connected. The fingerprint matching circuit 18 is, for example, an LSI (Large Scale).
Integrated Circuit)
Based on the video signal from the fingerprint collation sensor 6, a fingerprint image represented by the video signal is stored in advance in the image memory 22.
Is compared with the template image of the fingerprint stored in the fingerprint collation by performing, for example, pattern matching, and it is determined whether the fingerprint read by the fingerprint collation sensor 6 is a fingerprint registered in advance. Note that the fingerprint matching circuit 18
Together with the fingerprint collation sensor 6 constitutes the authentication means according to the present invention, that is, the fingerprint collation means.

The cryptographic processing circuit 20 (hash value generation means, encryption key generation means, hash value encryption means according to the present invention) comprises, for example, an LSI, and generates a hash value of document data and is based on a public key cryptosystem. A public key and a secret key are generated, and the hash value is encrypted with the secret key.

The liquid crystal monitor 8 (information output means according to the present invention) is connected to the bus line 12 through a liquid crystal controller 24, and under the control of the liquid crystal controller 24, data transmitted from the CPU 14 through the bus line 12. Display the document based on the U above
The SB cable 10 is connected to the bus line 12 through a USB controller 26, and the USB cable 1
0 allows the CPU 14 to exchange data with an external device.

Next, the operation of the digital signature device 2 configured as described above will be described. Here, as an example, the electronic signature device 2 is connected via a USB cable 10 to a personal computer (not shown), the document data to be electronically signed is supplied from the personal computer, and the result is also output to the personal computer. I do. When performing an electronic signature using the electronic signature device 2, the signer first operates the personal computer to cause the electronic signature device 2 to output, for example, data of a check to be electronically signed, and to instruct execution of the electronic signature. Thus, in the electronic signature device 2, the CPU 14 transmits the document data to the USB cable 10 and the USB controller 2
6 and received through the bus line 12 and stored in the program memory 16;
And the LCD monitor 8 through the LCD controller 24
, And an image of the check is displayed on the screen as shown in FIG.

The signer checks the contents of the check by looking at this display, and places his / her finger 28 on the fingerprint collation sensor 6 if there is no mistake in the contents. Fingerprint collation sensor 6
When the finger 8 is placed, the fingerprint is read from the finger 8 to generate a fingerprint video signal and output to the fingerprint matching circuit 18. Then, the fingerprint matching circuit 18 compares the fingerprint image represented by the video signal with the template image of the fingerprint stored in advance in the image memory 22 by performing, for example, pattern matching and the like, and is read by the fingerprint matching sensor 6. It is determined whether the registered fingerprint is a registered fingerprint.
If the determination result is positive, the fingerprint matching circuit 18 notifies the CPU 14 of the determination.

As a result, the CPU 14
0, and supplies the document data stored in the program memory 16 to the encryption processing circuit 20.
Then, the cryptographic processing circuit 20 generates a hash value of the supplied document data, and among the public key and the secret key generated in advance based on the public encryption key method, uses the secret key to generate the hash value. Encrypt.

The CPU 14 receives the encrypted hash value, and since the signer has been authenticated as described above, the CPU 14 operates as hash value output means and outputs the hash value from the USB controller 26 to the personal computer through the USB cable 10. . Thus, the digital signature is completed, and the encrypted hash value is then passed from the personal computer to the recipient via a communication network or a storage medium.

As described above, in the present embodiment, the data of the document image displayed by the liquid crystal monitor 8 and the data used by the cryptographic processing circuit 20 to generate the hash value are always the same, so that the signer is always required. An electronic signature is performed only on the confirmed data.

In this embodiment, the authentication is performed using the fingerprint of the signer. However, the authentication of the signer can be performed by various techniques, for example, based on other biometrics such as the retina of the signer. It is also possible to determine whether or not is a specific person registered in advance. It is also possible to perform authentication using the voiceprint of the signer.

Further, by incorporating a writing pressure sensor in the electronic signature device 2, the signer can be authenticated based on a change in writing pressure when the signer writes characters. At this time, if the pen pressure sensor is superimposed on the display unit of the liquid crystal monitor 8, the signer can perform authentication by signing the signature field of an image such as a check on the monitor. It is easy to understand. FIG. 3 is an external view showing an example of the digital signature device 30 having such a configuration. A transparent panel-shaped pen pressure sensor 34 is superposed on the display unit 32 of the liquid crystal monitor 8, and the signer can sign on this.

It is also possible to provide a password input means such as a keyboard, and compare the input password with a pre-registered password by, for example, the CPU 14 as a verification means to perform authentication. . It is also effective to use not only a single authentication unit but also a combination of a plurality of authentication units.

In this embodiment, the liquid crystal monitor 8 is used as the information output means. However, a configuration may be adopted in which the contents of the document are read out and notified to the signer. FIG. 4 is an external view showing another embodiment of such a configuration. In the electronic signature device 36 shown in FIG. 4, a speaker 38 is provided instead of the liquid crystal monitor 8, and the contents of the document to be signed are output as audio information through the speaker 38. The signer can listen to this sound, confirm the contents of the document, and sign. Note that it is of course possible to use an earphone instead of the speaker 38.

Further, an output terminal for outputting document data to be signed as a video signal and an output terminal for outputting document data as an audio signal are provided as information output means.
A device that actually displays an image or emits sound can be connected to the outside. In the electronic signature device 2, the connection with an external device such as a personal computer is performed by the USB system. However, it is of course possible to use an interface based on the RS232C standard.

[0024]

As described above, in the electronic signature apparatus of the present invention, the information output means outputs information representing data to be electronically signed, and the signer performs the electronic signature based on the output result. You can check the contents of the data you need. Then, the hash value generation means generates a hash value based on the data to be digitally signed. Thereafter, the hash value encryption unit encrypts the hash value generated by the hash value generation unit using the secret key generated by the encryption key generation unit, and the hash value output unit authenticates that the signer is a specific person. If the means determines,
The hash value encrypted by the hash value encryption means is output. As described above, in the present invention, the data from which the information output means outputs information for content confirmation and the data used by the hash value generation means for generating the hash value are always the same, and therefore, the signer must always confirm the data. An electronic signature is performed only on data.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an example of an electronic signature device according to the present invention.

FIG. 2A is an external view showing an electronic signature device according to an embodiment, and FIG. 2B is a plan view showing a check displayed on a liquid crystal monitor.

FIG. 3 is an external view showing an embodiment using a pen pressure sensor.

FIG. 4 is an external view showing an embodiment using a speaker.

FIG. 5 is a configuration diagram illustrating an example of a conventional digital signature device.

[Explanation of symbols]

2 ... Electronic signature device, 4 ... Device housing, 6 ... Fingerprint collation sensor, 8 ... LCD monitor, 10 ... USB cable, 12 ... Bus line, 14 ... CPU, 16 ...
Program memory, 18 ... fingerprint matching circuit, 20 ...
Encryption processing circuit, 22 image memory, 24 liquid crystal controller, 26 USB controller, 28
... finger, 30 ... electronic signature device, 32 ... display unit, 34 ...
... pen pressure sensor, 36 ... electronic signature device, 38 ... speaker, 102 ... electronic signature device, 104 ... fingerprint collator, 106 ... personal computer (personal computer),
108 ... Check, 110 ... Fingerprint collation sensor, 11
2. Cable.

Claims (11)

[Claims] An authentication unit configured to determine whether a signer is a specific person registered in advance; an information output unit configured to output information representing data to be subjected to an electronic signature; Hash value generation means for generating a hash value from power data, encryption key generation means for generating a public key and a secret key based on a public key cryptosystem, and using the secret key generated by the encryption key generation means, A hash value encryption unit that encrypts the hash value generated by the hash value generation unit; and, if the authentication unit determines that the signer is a registered specific person, the hash value encryption unit An electronic signature device comprising: a hash value output unit that outputs the encrypted hash value. 2. The electronic signature apparatus according to claim 1, wherein the authentication unit determines whether the signer is a specific person registered in advance based on the signer's biometrics. 3. The method according to claim 1, wherein the authentication unit reads a fingerprint from the signer's finger and determines whether the read fingerprint is a pre-registered fingerprint. The electronic signature device according to claim 1. 4. The electronic signature device according to claim 1, wherein the authentication unit determines whether the signer is a specific person registered in advance based on a voiceprint of the signer. 5. The method according to claim 1, wherein the authentication unit determines whether the signer is a specific person registered in advance based on a change in pen pressure when the signer writes a character. Item 2. The electronic signature device according to Item 1. 6. A password input means for inputting a password by a signer, and a collation means for judging whether or not a password input through the password input means matches a password registered in advance. 2. The electronic signature device according to claim 1, comprising: 7. The liquid crystal display device according to claim 1, wherein the information output unit includes a liquid crystal display device, and displays the data to be subjected to the electronic signature as character information on the liquid crystal display device.
Electronic signature device as described. 8. The electronic signature device according to claim 1, wherein the information output means includes a speaker or an earphone, and outputs the data to be subjected to the electronic signature as audio information through the speaker or the earphone. 9. An electronic signature apparatus according to claim 1, wherein said information output means includes an output terminal for outputting data to be digitally signed as a video signal. 10. The electronic signature device according to claim 1, wherein said information output means includes an output terminal for outputting data to be subjected to said electronic signature as an audio signal. 11. The information output means includes a liquid crystal display device, displays the data to be subjected to the electronic signature on the liquid crystal display device as character information, and the authentication means arranges the data on a display unit of the liquid crystal display device. Including a pen pressure sensor installed,
2. The method according to claim 1, wherein the signer determines whether the signer is a specific person registered in advance based on a change in writing pressure when the signer writes a character on the writing pressure sensor.
Electronic signature device as described.