JPH096237A - Filing system - Google Patents

Abstract

PURPOSE: To sign a document n a practically acceptable handling time even if the number of the document pages becomes more than 100 pages by hashing reduced data of the document and producing compressed characters. CONSTITUTION: In a sign operation, a digital sign portion 5 conducts hashing processing of reduced data of a document to produce a compressed sentence, and enciphers the same using a secret key corresponding to a signer ID so as to produce an authenticator. The reduced data is non-compressed type (not coded type) data which is produced by reducing actual data, and is stored in a document information portion 6. In verification operation, the digital sign portion 5 decodes the authenticator using an open key in response to the signer ID so as to restore the compressed sentence (a compressed sentence'). The compressed sentence is produced by conducting a hashing processing on the reduced data of the document. Comparing the compressed sentence and the compressed sentence', when these coincide with each other, it is determined that the document to be verified has not been altered.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a filing system used for digital signatures, databases, document management, image processing, etc., and particularly for high-speed digital signatures even when the amount of data is enormous. Regarding the system.

[0002]

2. Description of the Related Art Conventionally, as a method of digitally signing document data or the like, Japanese Patent Laid-Open No. 05-249892 aims at simultaneously confirming the validity of a signature and denying the signature and improving the reliability. The "digital signature system" of JP-A No. 05-333777 and the like are proposed. Also, as a method for digitizing digitized document data,
Books such as "Modern Cryptography" (Shinichi Ikeno, Kenji Koyama (The Institute of Electronics, Information and Communication Engineers)) and "The Story of Cryptography" (Hideki Imai (Japan Standards Association)) have been published. By the way, if we try to apply such technologies as "digital signature system", "modern cryptography" and "disclosure of cryptography" to filing systems used in digital signatures, databases, document management, image processing, etc. When performing the function of signing each document and the function of verifying the signature, it is necessary to scan the entire image of the entire document and process the image data obtained by this, every time signature / verification is performed. .

At this time, when signature processing is performed, first, as shown in FIG. 7, the actual data obtained by reading the image of the document to be signed is hashed to generate a compressed text, and then the signer ID is applied. Using the private key, the compressed text is encrypted to obtain an authenticator. When verifying the document to be verified, the authenticator is decrypted by using the public key corresponding to the signer ID as shown in FIG. 8, and the compressed sentence (this is called compressed sentence ') is restored. , The actual data obtained by reading the image of the document to be verified is hashed to generate a compressed sentence, and this compressed sentence and the compressed sentence 'are compared, and if they match, the verification target It is determined that the above document has not been tampered with, and if they do not match, it is determined that at least a part of the document has been tampered with.

However, in such a method, when the document standard is A4 size, even if the image data for one page is compressed, it becomes about several tens of kilobytes to several hundreds of kilobytes per page. So the number of pages is 100
When a document with more than one page is digitally signed and verified, the processing time becomes too long and it may not be possible depending on the processing system.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has a practically acceptable processing time even if the number of pages of a document to be signed exceeds 100 pages.
This document can be signed, and even if part of the document is tampered with and the characters in the reduced image data are crushed and become difficult to read, this is detected and rejected when the signature is verified. The filing system is capable of significantly improving the reliability of the signature.

[0006]

In order to achieve the above-mentioned object, claim 1
In the filing system according to the present invention described in (1), the compressed data obtained by reducing the actual data of the document to be signed when the signature is signed is generated as a compressed sentence, and then the key data corresponding to the signer ID is generated. And a signature processing unit that encrypts the compressed text to generate an authenticator, and decrypts the authenticator obtained by the signature processing unit using key data corresponding to the signer ID when performing verification. The compressed text is decompressed by hashing the reduced data obtained by reducing the actual data of the document to be verified, and the compressed text obtained by each of these processes is compared. ,
If all match, it is determined that the actual data to be verified has not been tampered with.
And a verification processing unit that determines that at least a part of the actual data to be verified has been tampered with.

Further, in the filing system according to the present invention as defined in claim 2, after the actual data of the document to be signed is reduced when the signature is performed, the reduced data obtained by hashing the compressed data to generate a compressed sentence, A signature processing unit that encrypts the compressed text by using the key data corresponding to the signer ID to generate an authenticator, and expands and reduces the actual data of the document to be verified at the time of verification for each page. After generating the verification reduced data, among the registered reduced data, the reduced data corresponding to the actual data of the document to be verified is compared with the verification reduced data, and if all match, verification is performed. Pre-verification process that tentatively determines that the target actual data has not been tampered with, and determines that at least part of the actual data subject to verification has been tampered with if it does not match After the processing by the pre-verification processing unit is completed, the authenticator obtained by the signature processing unit is decrypted by using the key data corresponding to the signer ID to restore the compressed text, and the pre-verification processing is performed. After generating the compressed sentence by hashing the verification reduced data of the document to be verified that is tentatively determined not to have been tampered with by the processing unit, the compressed sentence obtained by each of these processes is compared and If you do,
It has a post-verification processing unit that determines that the actual data to be verified has not been tampered with, and if even part of it does not match, determines that at least part of the actual data to be verified has been tampered with. It is characterized by that.

[0008]

In the above-mentioned structure, according to the invention of claim 1, after the signature processing unit reduces the actual data of the document to be signed by the signature processing unit, the reduced data obtained is hashed to generate a compressed sentence. , The signature processing unit uses the key data corresponding to the signer ID when performing verification by encrypting the compressed text using the key data corresponding to the signer ID and performing verification. After decompressing the authenticator obtained in step 1 to restore the compressed sentence, and reducing the actual data of the document to be verified to hash the reduced data obtained to generate the compressed sentence, The obtained compressed sentences are compared, and if all of them match, it is determined that the actual data to be verified has not been tampered with. If they do not match at least, at least one of the actual data to be verified is verified. Department changed By determined to be,
Even if the number of pages of the document to be signed is 100 or more, the document is signed in a processing time that is practically acceptable.

According to the second aspect of the present invention, when the signature is signed, the signature processing unit reduces the actual data of the document to be signed and hashes the reduced data to generate a compressed text, and then the signer When the verification is performed by encrypting the compressed text using the key data corresponding to the ID and performing verification, the verification preprocessing unit expands and reduces the actual data of the document to be verified for each page and verifies the data. After generating the reduced data, of the already registered reduced data, the reduced data corresponding to the actual data of the document to be verified is compared with the verified reduced data, and if all match, the verification target Tentatively determines that the actual data that is
If some of them do not match, it is determined that at least a part of the actual data to be verified has been tampered with, and after the processing of this pre-verification processing unit ends, the post-verification processing unit handles the signer ID. Using the key data to decrypt the authenticator obtained in the signature processing unit to restore the compressed text, the verification target document that has been tentatively determined not to be tampered with in the verification preprocessing unit After hashing the verification reduced data to generate a compressed text, the compressed texts obtained by each of these processes are compared, and if all match, it is determined that the actual data to be verified has not been tampered with. , Even if some of them do not match, by determining that at least a part of the actual data to be verified has been tampered with,
Even if part of the document is tampered with and the characters in the reduced image data are crushed and become difficult to read, this is detected and rejected when verifying the signature, thereby significantly improving the reliability of the signature. Improve to.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described in detail with reference to the embodiments shown in the accompanying drawings. FIG. 1 is a block diagram showing an embodiment of a filing system according to the present invention. The filing system shown in this figure has a keyboard and the like, which is operated by a signer to input document data and various commands, and a filing system, which has a mouse and the like to input pointing data and the like by a signer. A mouse input unit 2 that is operated when inputting, an operation unit 3 that takes in the operation contents of the mouse input unit 2 and the key input unit 1 and generates data and commands necessary for computer processing, and this operation A control unit 4 is provided for performing various data processing and controlling the entire apparatus based on data and commands output from the unit 3.

Further, under the control of the control unit 4, this filing system uses document data, for example, as shown in FIG. 2, reference to document name, actual data, etc., signer ID, authenticator, and other data. A document ledger,
Hashing of the data stored in the document information unit 6 under the control of the document information unit 6 in which the actual data of the document, reduced data, etc. are stored,
A digital signature unit 5 that manages the signer ID, secret key / public key, signs, and decrypts, and a document to be processed, a processed document, and an operation screen under the control of the control unit 4. A display unit 7 for displaying and a printing unit 8 for fetching the content of a document to be printed and printing it out under the control of the control unit 4 are provided. In this case, the reduced data stored in the document information section 6 is data in a non-compressed format (uncoded format) created by reducing the actual data, and the document information section 6 is replaced or edited. Each time the content of the actual data stored in is changed, the control section 4 automatically creates the content and updates the registered content up to that point.

Next, the operation of this embodiment will be described with reference to the block diagram shown in FIG. 1, the schematic diagram shown in FIG. 2, and the schematic diagrams shown in FIGS. <Signing Operation> First, in the signing operation, the signer operates the key input unit 1 and the mouse input unit 2 to instruct a document name to be signed, and the operation unit 3 outputs the data suitable for computer processing. When converted into a command or a command, the control unit 4 reads out the reduced data and the signer ID of the designated document data among the document data stored based on the contents of the document ledger stored in the document information unit 6. It is then transferred to the digital signature unit 5.

Thereafter, the digital signature unit 5 starts the signature process under the control of the control unit 4, and after the reduced data of the document is hashed to generate a compressed sentence as shown in FIG. The compressed text is encrypted using the private key corresponding to the signer ID, and the authenticator is generated. Then, under the control of the control unit 4, the authenticator obtained by this processing is transferred to the document information unit 6 and registered in the document ledger stored in the document information unit 6.

<Verification Operation> After that, the signer operates the key input unit 1 and the mouse input unit 2 to instruct a document name to be verified, and the operation unit 3 outputs the data suitable for computer processing. When converted into a command, the authenticator of the specified document name among the authenticators stored based on the contents of the document ledger stored in the document information unit 6 by the control unit 4 and the signer ID, The reduced data and the data are read out and transferred to the digital signature unit 5. Then, under the control of the control unit 4, the digital signature unit 5 starts the verification process, the public key corresponding to the signer ID is used as shown in FIG. (This is called a compressed sentence ') is restored, and the reduced data of the document is hashed to generate a compressed sentence.

Next, the digital signature unit 5 compares the compressed text with the compressed text ', and if they match, it is determined that the document to be verified has not been tampered with, and they also match. If not, it is determined that at least a part of the document to be verified has been tampered with, and the determination result is supplied to the control unit 4 and displayed on the display unit 7. As described above, in this embodiment, when the signature is performed, the image data (actual data) obtained by reading the image of the document to be signed is reduced, and the reduced data obtained by the hashing process is used for the reduced data. When the verification is performed, the verifier of the document to be verified is decrypted using the public key to reproduce the compressed text ', and the compressed text' is reproduced. , The compressed data of the document to be verified is compared with the compressed text obtained by hashing, and it is determined based on the comparison result whether the document to be verified has not been tampered with. The number of pages of the target document is 100
This document can be signed in a processing time that is practically acceptable even if the number of pages exceeds the limit.

Further, in the above-described embodiment, the signature operation and the verification operation are performed to sign and verify the document in the procedure shown in the schematic diagrams of FIGS. 3 and 4. For example, when the correspondence between the actual data of the document to be signed and verified and the reduced data is not guaranteed, the document may be signed and verified according to the procedure shown in FIGS.

<Signing Operation> In this case, when a signature is made, as shown in FIG. 5, the signer operates the key input unit 1 or the mouse input unit 2 to instruct the name of the document to be signed, and the operation unit. When this is converted into data or instructions suitable for computer processing by 3, the control unit 4 selects the specified document data among the document data stored based on the contents of the document ledger stored in the document information unit 6. The actual data, the reduced data, and the signer ID are read out and transferred to the digital signature unit 5. Thereafter, the digital signature unit 5 starts the signature process under the control of the control unit 4, and if there is reduced data of the actual data as shown in FIG. 5, the reduced data is hashed to generate a compressed sentence. Is
If there is no reduced data of the actual data, reduction processing is performed on the actual data, the reduced data obtained by this is subjected to hashing processing to generate a compressed sentence, and then the private key corresponding to the signer ID is used. Then, the compressed text is encrypted and an authenticator is generated. Then, under the control of the control unit 4, the authenticator obtained by this processing is transferred to the document information unit 6 and registered in the document ledger stored in the document information unit 6.

<Verification Operation> When performing verification, the signer operates the key input unit 1 or the mouse input unit 2 to instruct a document name to be verified, and the operation unit 3 is suitable for computer processing. Of the document to be verified among the actual data of the document stored based on the contents of the document ledger stored in the document storage unit by the control unit 4 and this document, The reduced data of the document used at the time of signature corresponding to is read and transferred to the digital signature unit 5.

Then, under the control of the control unit 4, the digital signature unit 5 starts the verification process, and as shown in FIG. 6, the actual data is expanded for each page and then reduced to create reduced data '. Then, the reduced data 'is compared with the original reduced data corresponding to the document to be verified transferred from the document information section 6, and if they do not match, the unmatched page is tampered with. It is determined that the control is performed and the determination result is passed to the control unit 4 and displayed on the display unit 7.

Further, the comparison and collation are performed up to the last page, and if the reduced data 'and the reduced data match on all pages, the control unit 4 stores the document ledger stored in the document information unit 6. Of the stored authenticators, the authenticator obtained by the signature processing corresponding to the document to be verified and the signer ID are read out and transferred to the digital signature unit 5. .

Then, under the control of the control unit 4, the digital signature unit 5 uses the public key corresponding to the signer ID to decrypt the authenticator, and the compressed text (this compressed text
The compressed data of the document to be verified is hashed to generate a compressed sentence, and the compressed sentence and the compressed sentence 'are compared, and they are matched. If so, it is determined that the document to be verified has not been tampered with, and if they do not match, it is determined that at least a part of the document to be verified has been tampered with, and the determination result is sent to the control unit 4. Supplied,
It is displayed on the display unit 7.

Thus, even if the correspondence between the actual data and the reduced data is not guaranteed, the document to be verified can be verified and a part of the document is tampered with. For example, in the document
After the signer signed a document "¥ 110,000",
The tamperer can only check the relevant part of the actual data with the "budget \ 17
Even if the characters in the reduced image data are crushed and it is difficult to distinguish between "1" and "7" when the document data is falsified to "0000" and the document data after falsification is reduced, this is detected. You can find out illegal tampering.

As described above, in this embodiment, when the signature is applied, the image data (actual data) obtained by reading the image of the document to be signed is reduced, and the reduced data is compressed by the hashing process and the secret key is used. Reduced data 'that is the actual data of the document to be verified when it is verified by generating an authenticator by performing encryption using
And the reduced data already registered are compared, and if they match, the verifier corresponding to the document to be verified is decrypted using the public key and the compressed sentence 'is reproduced. Then, compare this compressed sentence 'with the compressed sentence obtained by hashing the reduced data of the document to be verified,
Since it is determined whether the document to be verified has been tampered with based on the result of this comparison, even if the number of pages of the document to be signed exceeds 100 pages,
This document can be signed in a practically acceptable processing time, and even if part of the document is tampered with and the characters in the reduced image data are crushed and become difficult to read, the signature This can be detected and rejected when performing verification of the, which can greatly improve the reliability of the signature.

Further, in this embodiment, the processing speed of the verification becomes slower than the signature procedure and the verification procedure shown in FIGS. 3 and 4, but the normal verification processing, for example, only one department in the company. If the user does not have to doubt the user, such as when using the filing system according to the present invention, the number of verification processes is sufficiently smaller than the number of signatures.
In practice, no problem will occur.

[0025]

As described above, according to the present invention, in claim 1, even if the number of pages of the document to be signed is 100 pages or more, the processing time is practically sufficient. Documents can be signed. Also,
According to the second aspect, even if a part of the document is tampered with and the characters in the reduced image data are crushed and become difficult to read,
This can be detected and rejected when performing signature verification, which can greatly improve the authenticity of the signature.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a filing system according to the present invention.

FIG. 2 is a schematic diagram showing an example of a document ledger or the like stored in a document information section shown in FIG.

FIG. 3 is a schematic diagram showing an example of a signature operation of the filing system shown in FIG.

FIG. 4 is a schematic diagram showing an example of a verification operation of the filing system shown in FIG.

FIG. 5 is a schematic view showing an example of a signature operation used in another embodiment of the filing system according to the present invention.

FIG. 6 is a schematic diagram showing a verification operation example used in another embodiment of the filing system according to the present invention.

FIG. 7 is a schematic diagram showing an example of signature processing of a document using a conventionally known signature technique.

FIG. 8 is a schematic diagram showing an example of a document verification process using a conventionally known signature technique.

[Explanation of symbols]

1 key input part, 2 mouse input part, 3 operation part,
4 control section, 5 digital signature section (signature processing section, verification processing section, pre-verification processing section, post-verification processing section), 6 document information section, 7 display section, 8 printing section

Claims (2)

[Claims] 1. When a signature is signed, compressed data is generated by hashing the reduced data obtained by reducing the actual data of the document to be signed, and then the key data corresponding to the signer ID is used. A signature processing unit that encrypts the compressed text to generate an authenticator, and, when performing verification, uses the key data corresponding to the signer ID to decrypt the authenticator obtained by the signature processing unit and compress the compressed text. After compressing the actual data of the document to be verified and hashing the reduced data obtained to generate a compressed sentence, the compressed sentences obtained by each of these processes are compared and all match. If so, it is determined that the actual data to be verified has not been tampered with, and if even part of them does not match, it is determined that at least a part of the actual data to be verified has been tampered with, It is equipped with Filing system to be. 2. When a signature is signed, compressed data is generated by hashing the reduced data obtained by reducing the actual data of the document to be signed, and then the key data corresponding to the signer ID is used. A signature processing unit that encrypts the compressed text and generates an authenticator, and when performing verification, after expanding and reducing the actual data of the document to be verified for each page to generate verification reduced data,
Of the registered reduced data, the reduced data corresponding to the actual data of the document to be verified is compared with the verified reduced data, and if all match, the actual data to be verified has not been tampered with. The pre-verification processing unit that determines that at least a part of the actual data to be verified has been tampered with if it does not match even partially, and the signature A verification object that is tentatively determined not to be tampered with by the verification preprocessing unit while decrypting the authenticator obtained by the signature processing unit using the key data corresponding to the person ID to restore the compressed text. After generating the compressed sentence by hashing the verification reduced data of the document, the compressed sentences obtained by each of these processes are compared, and if all match, the actual data to be verified has not been tampered with. And a post-verification processing unit that determines that at least a part of the actual data to be verified has been tampered with even if a part of them does not match, and a filing system.