JP4167137B2 - Signature generation method and data exchange system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to data exchange between computer systems connected on a communication network. In particular, it relates to a communication proxy service that performs data exchange in accordance with a specific communication protocol, and an effective application field includes inter-company electronic commerce.
[0002]
[Prior art]
When exchanging data between computer systems connected to an open communication network such as the Internet, security requirements such as security protection and tampering of communication data, authentication of the communication partner, and prevention of non-repudiation regarding transmission and reception of communication data, etc. Is important.
In particular, in the case of business-to-business electronic commerce, these security requirements are indispensable when important data is exchanged such as ordering transactions.
Generally, public key cryptography (PKI) technology is widely used as a technology for solving such security problems.
For example, as techniques used in electronic signatures, RSA encryption (for example, see Non-Patent Document 1) and DSA encryption are used as encryption algorithms, and MD5 (for example, see Non-Patent Document 2) and SHA- 1 and the like are in widespread use, and these techniques can also be applied to the present invention.
[0003]
Public key cryptography application technologies for security requirements during data exchange include security functions for communication channels such as TLS (see Non-Patent Document 3, for example) and S / MIME (for example, non-patents). There is a technique for performing digital signature and encryption on a message storing data exchanged through a communication path, such as XML reference (see Reference 4) and XML electronic signature (see Non-Patent Reference 5, for example).
In addition, there is a MIME format as a format for packaging a message (see, for example, Non-Patent Document 6).
In particular, encryption and electronic signatures for messages are characterized by the fact that security effects can be obtained not only during data exchange but also afterwards, for example, so that the trading partner cannot deny the contents of transaction documents at a later date. It is possible to do.
In recent years, inter-company electronic commerce (B2B) using the Internet, which is an open network environment, has been realized, such as RosettaNet (for example, see Non-Patent Document 7), ebXML (for example, Non-Patent Document 8), etc. Standard specifications are being developed.
These standard specifications also define standards for standard exchange protocols (message format and communication protocol) in data exchange, and further define a format for adding an electronic signature to a message as described above.
With the advent of such standard specifications, there is an increasing expectation for communication agency services that comply with the standard specifications.
Depending on the standard specifications, it may be difficult to handle such as the server computer must be operated to exchange data, or depending on the company, it is necessary to support multiple standard specifications at the same time, resulting in high operating costs. It depends.
[0004]
FIG. 1 shows an example of a system form of a communication proxy service that performs data exchange communication proxy in accordance with standard specifications.
There are sites where computers of respective companies are installed in a communication agent 0101, a communication consignor 0102 (company A) as a service user, and communication destinations (0103, 0104) (company B, company C).
At these sites, a communication proxy server 0111 (communication agent computer), a communication entrustor computer 0112, and communication destination computers (0113, 0114) are installed, and are connected by a communication network 0131.
The communication consignment company and the communication destination company exchange data via a communication agent based on standard exchange protocols (standard exchange protocol α0122 and standard exchange protocol β0123) compliant with standard specifications.
At this time, the communication agent 0102 and the communication agent 0101 exchange data in accordance with a communication proxy server-specific exchange protocol 0121 (hereinafter referred to as a unique exchange protocol) defined by the communication agent 0101, and the communication agent 0101 performs standard exchange. By converting to the protocol (0122, 0123), the communication destination (0103, 0104) (company B, company C) exchanges data with the communication consignor 0102 (company A) without being aware of the communication agent 0101. I can do it.
At this time, since the communication agent 0101 selects and converts an appropriate standard exchange protocol according to the communication destination (0103, 0104) (company B, company C), the communication consignor 0102 (company A) communicates. Data can be exchanged without being aware of the difference in exchange protocol.
In addition, there is a publicly known technique for the secret key information delegation problem (see, for example, Patent Document 1), and a publicly known technique for confirming the validity of received data using an electronic signature in data communication via an intermediary (for example, Patent Document 2).
[Non-Patent Document 1]
RFC2437: "PKCS # 1: RSA Cryptography Specifications, Version 2.0" B. Kaliski et al., 1998
[Non-Patent Document 2]
RFC1321: "The MD5 Message-Digest Algorithm", R. Rivest, 1992
[Non-Patent Document 3]
RFC2246: "The TLS Protocol Version 1.0", T. Dierks et al., IETF Network Working Group, 1999
[Non-Patent Document 4]
RFC2311: "S / MIME Version 2 Message Specification", S.Dusse et al., IETF Network Working Group, 1998
[Non-Patent Document 5]
"XML-Signature Syntax and Processing", W3C Recommendation, 2002
[Non-Patent Document 6]
RFC1521: "MIME (Multipurpose Internet Mail Extensions) Part One: Mechanisms for Specifying and Describing the Format of Internet Message Bodies", N. Borenstein et al., 1993
[Non-Patent Document 7]
"RosettaNet Implementation Framework: Core Specification, Version V02.00.01", RosettaNet, 2002
[Non-Patent Document 8]
"ebXML Message Service Specification, Version 2.0", OASIS ebXML Messaging Service Technical Committee, 2002
[Patent Document 1]
Japanese Patent Application No. 2002-311829 “IC Card”
[Patent Document 2]
JP 2002-24176 A "Data Communication System, Sender Device, Intermediary Device, Receiver Device, and Recording Medium"
[0005]
[Problems to be solved by the invention]
Such communication agency services have the following problems.
That is, when an electronic signature is added to a standard format message to be transmitted to a communication destination company, the electronic signature value is calculated by the communication proxy server, which requires the private key information of the communication consignment company. .
This is because the electronic signature for the message is generated for the purpose of preventing non-repudiation of the transaction content, for example, and must be generated and attached using the private key information of the communication consignment company that is the transaction party.
However, in the PKI technology, the secret key information corresponds to a company seal, and when the secret key information is entrusted to a communication agent, there is a risk for both the service provider and the service user.
In Patent Document 1, secret key information to be entrusted is stored in an IC card, and when performing an electronic signature, data to be signed is checked based on a restriction text stored in the IC card.
However, there is a problem that it is difficult to implement when the restriction conditions of the data to be signed are complicated.
In Patent Document 2, the validity of received data is confirmed using an electronic signature in data communication via an intermediary.
However, in Patent Document 2, the receiver needs to be aware of the presence of an intermediary, and cannot be applied to a case where data is exchanged with a service user transparently based on an exchange protocol compliant with standard specifications.
An object of the present invention is to provide an electronic signature of a communication consignor without delegating a secret key to the communication agent for the standard format message that the communication agent transfers to the communication destination at the request of the communication agent. It is to be able to grant.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a data exchange in which a communication consignor computer and a communication destination computer connected via a communication network via a communication agent computer relay each other and exchange data with each other. In the system, the message format including the exchange data used when the exchange data is transmitted and received between the communication entrustor computer and the communication agent computer is the first format, and is exchanged between the communication agent computer and the communication destination computer. The message format including the exchange data used when transmitting / receiving data is the second format,
When the exchange data transmitted as a message in the first format from the communication consignor computer to the communication agent computer is converted into a second format message in the communication agent computer and transmitted to the communication destination computer, the second format Is a signature generation method for attaching a digital signature of a communication consignor based on public key cryptography to the message of
The communication agent computer obtains a digest value for the second type message, transmits a signature request message including the digest value to the communication consignor computer, and the communication consignor computer performs the response to the digest value. Enciphering with the secret key of the communication consignor, obtaining an electronic signature value for the message of the second format, sending a signature data message including the electronic signature value to the communication agent computer,
In the communication agent computer, the electronic signature of the communication consignor is attached to the message in the second format using the electronic signature value.
In addition, a communication entrustor computer and a communication destination computer connected via a communication agent computer via a communication network relay the communication agent computer and exchange data with each other, and the communication entrustor computer and the communication agent computer A message format including the exchange data used when the exchange data is transmitted / received between the communication agent computer and the communication destination computer. The format is the second format,
When the exchange data transmitted as a message in the first format from the communication consignor computer to the communication agent computer is converted into a second format message in the communication agent computer and transmitted to the communication destination computer, the second format Is a data exchange system that gives a digital signature of a communication consignor based on public key cryptography to the message of
The communication agent computer has means for obtaining a digest value for the message of the second format, and means for transmitting a signature request message including the digest value to the communication consignor computer,
The communication entrustor computer encrypts the digest value with the secret key of the communication entrustor, obtains an electronic signature value for the second format message, and a signature data message including the electronic signature value. A means for transmitting to the communication agent computer;
The communication agent computer has means for assigning the electronic signature of the communication consignor to the message in the second format using the electronic signature value.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
First, the outline of the present invention will be described with an example.
FIG. 17 shows a schematic configuration of the above example.
Data exchange between the communication agent and the communication destination company B is performed by a standard exchange protocol using a standard format message, and data exchange between the communication agent and the communication consignor company A is data specific to the communication agent. This is done using an exchange protocol.
The communication consignor company A (hereinafter abbreviated as A) transmits the exchange data to the communication destination company B (hereinafter abbreviated as B) via a communication agent.
First, A (1) creates exchange data to be transmitted, and (2) sends a data transfer request to the communication consignor.
The communication consignor receives the data transfer request from A, (3) packages the transfer data into a standard format message, and (4) calculates the digest value of the exchange data and the standard format message. A signature request including the value is generated, and the signature request is signed with the secret key (Sc) of the communication agent. (5) A signature request including the digest value and the signature is transmitted to A.
A receives the signature request, (6) verifies the signature of the communication agent using the public key (Pc) of the communication agent, (7) calculates the digest value of the original exchange data, and sends it Compared with the digest value of the exchange data in the book title request that has been received,
(8) The signature request from the communication agent is saved, and (9) A signature value for the standard format message is calculated, that is, the digest value of the standard format message is set to A's private key (S _A ) And (10) return the signature value to the communication agent. That is, A's signature value for the standard format message is returned.
The communication agent (11) embeds A's signature value in the standard format message, and (12) transmits a standard format message including header information, exchange data, and A's signature value to B.
In B, (13) the received standard format message is sent to A's public key (P _A ) To confirm.
As described above, the exchange data is transmitted from A to B. By transmitting in this way, the communication agent does not need to hold and manage A's secret key, and the communication consignor company A does not need to pass A's secret key to the communication agent. Thereby, risks such as leakage of key information can be avoided.
For example, if this example is applied to the data exchange in the business-to-business electronic commerce (B2B), the company A that does not support the data exchange by the B2B standard exchange protocol entrusts the communication agent by the B2B standard exchange protocol. By doing so, a case may be considered when exchanging data such as business documents with the company B of the business partner supporting the B2B standard exchange protocol.
[0008]
Hereinafter, an example of an embodiment of the present invention will be described with reference to the drawings.
First, the system configuration in the present embodiment will be described with reference to FIGS.
As shown in FIG. 1, each computer of the communication entrustor computer 0112, the communication proxy server 0111, and the communication destination computer (0113, 0114) (company B, company C) includes a CPU 0141, a memory 0142, a communication device 0143, and a display device 0144. , An input device 0145, and an auxiliary storage device 0146.
The memory 0142 stores each program to be described later, and the processing of each program is executed by the CPU 0141.
The computers are connected to each other via a communication network 0131 by a communication device 0143.
The communication proxy server 0111 transfers the exchange data received from the communication entrustor computer 0112 to the communication destination computers (0113, 0114) (company B, company C). Conversely, the data transferred from the communication destination computer (0113, 0114) (company B, company C) is transmitted to the communication entrustor computer 0112.
At this time, communication between the communication consignor computer 0112 and the communication proxy server 0111 is performed according to a communication protocol specific to the communication proxy server (unique communication protocol 0121), and the communication proxy server 0111 and the communication destination computers (0113, 0114) (company B, An appropriate standard exchange protocol (0122, 0123) (α or β) corresponding to the communication destination computer is selected to communicate with the company C).
[0009]
Next, the configuration and outline of the processing program in each computer of the communication proxy server 0111 and the communication entrustor computer 0112 in this embodiment will be described with reference to FIG.
The processing program on the communication entrustor computer 0112 side includes processing programs of a business processing unit 0218, a communication entrustment control unit 0217, a unique format message processing unit 0213, a signature generation / verification processing unit 0212, and a communication processing unit 0211.
The business processing unit 0218 instructs the communication entrustment control unit 0217 to transmit the exchange data to the communication destination, and receives the exchange data received from the communication destination.
The communication processing unit 0211 performs message transmission / reception processing to other computers via the communication network 0131.
The signature generation / verification processing unit 0212 is based on a general encryption algorithm or digest value calculation algorithm, and is used for encryption calculation of an electronic signature value (generation of an electronic signature value by encryption of a digest value and reverse conversion thereof) The digest value is restored by decoding the value) and the digest value is calculated for the binary data.
The inherent format message processing unit 0213 uses the processing result of the signature generation / verification processing unit 0212 to generate and analyze various message formats to be transmitted / received in the inherent exchange protocol, and to attach and verify an electronic signature to the inherent format message and to calculate a digest value. I do.
The auxiliary storage device 0146 of the communication entrustor computer 0112 stores key information 0221 and transfer data information 0223.
[0010]
The processing program on the communication proxy server 0111 side includes processing programs of a message transfer control unit 0216, a standard format message processing unit, a specific format message processing unit 0213, a signature generation / verification processing unit 0212, and a communication processing unit 0211.
Here, the processing programs of the unique format message processing unit 0213, signature generation / verification processing unit 0212, and communication processing unit 0211 are the same as those on the communication entrustor computer 0112 side.
The standard format message processing unit 0214 generates and analyzes the exchange format message for each standard exchange protocol (α, β) of the communication destination computer (0113, 0114) (company B, company C), and assigns an electronic signature. Digest value calculation is performed.
The standard format message processing unit 0214 includes a sub-processing program for each standard format message, such as the α format message processing unit 0215.
The message transfer control unit 0216 performs overall control of the transfer process of the exchange data requested from the communication entrustor computer 0112 and the transfer process of the exchange data received from the communication destination computer (0113, 0114) to the communication entrustor computer. Do.
The auxiliary storage device 0146 of the communication proxy server 0111 stores key information 0221, transfer message information 0222, and communication entrustor management information 0224.
[0011]
5 to 8 show details of the management information stored in the auxiliary storage device 0146. FIG.
FIG. 5 shows the structure of the transfer data information table 0501.
The transfer data information table 0501 is a table for storing information (transfer data information 0223) regarding each data transfer process performed between the communication entrustor computer 0112 and the communication proxy server 0111.
The transfer identifier column 0511 stores a transfer identifier that uniquely identifies the executed transfer process.
The communication destination identifier column 0512 stores a company identifier that uniquely specifies a communication destination in each transfer process.
The transmission / reception type column 0513 indicates whether the transfer process is a transmission process to the communication destination computer (0113, 0114) or a reception process from the communication destination computer.
It takes one of the values “transmission” or “reception” depending on whether it is a transmission process or a reception process. The transfer request message column 0514, the signature request message column 0515, and the signature data message column 0516 are data exchanged between the two computers when the communication entrustor computer 0112 requests the communication proxy server 0111 to transmit the exchange data. Each of the transfer request message 0311, the signature request message 0331, and the signature data message 0341 (see FIG. 3) is stored.
Finally, the received data transfer message column 0517 stores a received data transfer message 0411 (see FIG. 4) transferred from the communication proxy server 0111 when receiving exchange data from the communication destination computers (0113, 0114).
Details regarding the data transfer request message 0311, the signature request message 0331, the signature data message 0341, and the received data transfer message 0411 will be described later.
[0012]
FIG. 6 shows the structure of the transfer message information table 0601.
The transfer message information table is a table for storing transfer message information 0222, and stores standard format messages exchanged with the communication destination computers (0113, 0114) via the communication proxy server 0111.
The transfer identifier column 0611 stores a transfer identifier that uniquely identifies each transfer process, as in the transfer data information table 0501 described above.
The communication entrustor identifier column 0612 is a column for storing the company identifier of the communication entrustor, and is used for specifying which communication entrustor is a transfer message when the communication agent has a plurality of communication entrustors. .
The communication destination identifier column 0613 is a company identifier that uniquely specifies a communication destination. The transmission / reception type column 0614 stores a value (either “transmission” or “reception”) for distinguishing whether the transfer message is transmitted to the communication destination or received from the communication destination.
Finally, the standard format message column 0615 stores the standard format message exchanged with the communication destination.
[0013]
FIG. 7 shows the structure of the communication entrustor management information table 0701.
The communication entrustor management information table 0701 is a table for storing communication entrustor management information 0224.
The communication entrustor identifier column 0711 stores a communication entrustor identifier that uniquely identifies the communication entrustor.
The communication destination identifier column 0713 stores a communication destination identifier indicating a communication destination that exchanges data with the communication entrustor (via a communication agent).
The exchange protocol column 0715 stores a standard exchange protocol used when exchanging data with the communication destination.
The communication destination network address column 0714 indicates addresses on the communication network used by the communication destination computers (0113, 0114).
The communication entrustor network address 0712 indicates a network address used by the communication entrustor computer 0112.
The communication entrustor network address 0712 is used, for example, when it is necessary to start a communication session from the communication agent server 0111 side in communication between the communication agent server 0111 and the communication agent computer 0112.
[0014]
FIG. 8 shows the structure of the key information table 0801.
The key information table is a table that stores key information 0221 of each company.
The company identifier column 0811 is a company identifier that uniquely identifies each company of a communication destination, a communication agent, and a communication consignor.
The public key column 0812 stores the public key of the company of the record.
The private key column 0813 stores the private key of the company of the record.
[0015]
Next, the procedure for actually performing the communication proxy process in the communication proxy server 0111 will be described separately for transmission and reception.
In the description of this procedure, the company identifier of the communication consignor is “A”, the company identifier of the communication destination is “B”, and the company identifier of the communication agent is “Z”.
Further, the secret key of the communication consignor A is SA0011, the public key is PA0012, the secret key of the communication destination B is SB0032, the public key is PB0031, the secret key of the communication agent Z is SZ0001, and the public key is PZ0002.
Each key information is stored in the key information table 0801 in the auxiliary storage device 0146 in each computer as shown in FIG.
[0016]
In this specification, the symbol dig (y) indicates the digest value of the data y.
The symbol sgn (x, y) represents the value of the electronic signature by x to y.
That is, the digest value dig (y) of y is encrypted using the secret key Sx of x.
In general, signature verification is performed by decrypting an electronic book name using a public key Px of x and comparing it with a digest value dig (y) of y.
A generally known algorithm can be applied to such digest value calculation and encryption processing.
The digest value calculation method for the message M depends on the individual message format, but is similarly expressed as dig (M).
Further, the value of the electronic signature for the message M is expressed as sgn (x, M), and the message digest value dig (M) is encrypted using the secret key Sx of x in the same manner as described above. Desired.
An example of a method for calculating a digest value for a message and a method for giving an electronic signature will be described in detail later.
[0017]
First, using FIG. 3 and FIG. 14, a processing procedure when a transfer request for exchange data is sent from the communication entrustor computer 0112 to the communication proxy server 0111 will be described.
FIG. 14 is a flowchart showing a processing procedure in each computer.
A portion surrounded by a broken line on the left side (1401) indicates processing steps executed by the communication proxy server 0111, and a portion surrounded by a broken line on the right side (1402) indicates processing steps executed by the communication entrustor computer 0112. Yes.
FIG. 3 is a data flow diagram showing the flow of data between the computers.
(Step 1451) The exchange data (D) (0301) and the communication destination identifier (company identifier of the communication destination) are transferred from the business processing unit 0218 to the communication entrustment control unit 0217, and a transfer is requested.
The communication entrustment control unit 0217 calls the unique format message processing unit 0213 to create a data transfer request message 0311.
[0018]
FIG. 9 shows the structure of the data transfer request message (MS1) 0311.
The data transfer request message 0311 includes a message header (HS1) 0312 and exchange data 0301.
Here, the exchange data 0301 is exchange data received from the business processing unit 0218.
In each field of the message header (HS1) 0312, a fixed value “data transfer request” is stored in the message type field 0901, and a company identifier (“A” in this example) is stored in the communication entrustor identifier field 0902. In the transfer identifier field 0903, a transfer identifier uniquely identifying this transfer request (in this example, “0001”), and in the communication destination identifier field 0904, a communication destination identifier (in this example, received from the business processing unit 0218). “B”) is set.
Here, the transfer identifier is numbered by the communication entrustment control unit 0217.
[0019]
(Step 1452): The communication entrustment control unit 0217 calls the communication processing unit 0211 and transmits the created data transfer request message 0311 to the communication proxy server 0111.
(Step 1411): In communication proxy server 0111, communication processing unit 0211 receives data transfer request message 0311 and passes it to message transfer control unit 0216.
The message transfer control unit 0216 calls the proper format message processing unit 0213, analyzes the received data transfer request message 0311, and acquires the message header (HS1) 0312 and the exchange data 0301.
Here, the message transfer control unit 0216 determines the message type from the message type field 0901 in the message header (HS1) 0312 and confirms that it is a “data transfer request”.
If the message type is “signature data” to be described later, the processing is executed from step 1418.
(Step 1412): The message transfer control unit 0216 identifies the communication consignor and the communication destination from the communication consignor identifier field 0902 and the communication destination identifier field 0904 of the message header (HS1) 0312.
Further, the exchange protocol column 0715 and the communication destination network address column 0714 are searched from the combination of the communication identifier of the communication consignor and the communication destination company identifier acquired in the communication consignee management information table 0701 of FIG. (In this example, “α” is acquired as the exchange protocol and “http://www.bbb.com/...” Is acquired as the communication destination network address.
)
(Step 1413): The message transfer control unit 0216 calls the sub-processing program 0215 of the standard format message processing unit 0214 that processes the standard format message of the standard exchange protocol specified in step 1412, and sends the standard format message (Mα) 0321. Create (here, an α-format message is generated).
[0020]
FIG. 13 shows the structure of a standard format message (Mα) 0321 (same for 0351 and 0401).
The standard format message (Mα) includes a message header (Hα) 1311 and exchange data 1312.
In each field of the message header (Hα) 1311, the exchange identifier field 1321 contains an exchange identifier for uniquely identifying each message, the sender identifier field 1322 contains the company identifier of the sender of this message, and the receiver identifier field. In 1323, the company identifier of the recipient of this message is set.
In addition, a value of the sender's electronic signature for this message is calculated and set in the sender electronic signature 1313 (sender electronic signature value 1314).
The fields of the message header (Hα) 0322 of the standard format message (Mα) 0321 are set as follows according to the values of the fields of the message header (HS1) 0312 of the data transfer request message (MS1) 0311.
First, in the sender identifier field 1322, the company identifier of the communication consignor acquired from the communication consignor identifier field 0902 is set.
In the receiver identifier field 1323, a transfer destination company identifier acquired from the communication destination identifier field 0904 is set.
Finally, the value obtained from the transfer identifier field 0903 is set in the exchange identifier field 1321 (the exchange identifier and the transfer identifier have the same contents, but the message between the communication proxy server and the communication destination computer). Is referred to as an exchange identifier, and is referred to as a transfer identifier when a message is transmitted between the communication proxy server and the communication entrustor computer).
At this time, it is noted that the sender electronic signature 1313 is not yet given to the standard format message (Mα) 0321.
In the present embodiment, the header fields of the unique format message and the standard format message are simply associated as described above, but the identifier code system and expression format do not always match between the two exchange protocols. In general, the communication proxy server 0111 may need to perform these conversion processes and association management. However, these details do not have any influence on the implementation of the present invention, and do not limit the scope of the present invention.
[0021]
(Step 1414): The message transfer control unit 0216 calls the proper format message processing unit 0213, and calculates the digest value (dig (MS1)) of the data transfer request message received in Step 1411.
(Step 1415): The message transfer control unit 0216 calls the standard format message processing unit 0214 (α format message processing unit 0215), and the digest value (dig (Mα)) of the standard format message (Mα) 1321 generated in Step 1413. ).
(Step 1416): The message transfer control unit 0216 calls the proper format message processing unit 0213, creates a signature request message (MS2) 0331, and gives the electronic signature (sgn (Z, MS2)) of the communication agent Z. .
At this time, the secret key SZ0001 of the communication agent Z stored in the key management table 0801 is used.
Also, the unique format message processing unit 0213 can perform digest value calculation and electronic signature value calculation of each data based on a general encryption algorithm by calling the signature generation / verification processing unit 0212.
[0022]
FIG. 10 shows the structure of the signature request message (MS2) 0331.
The signature request message (MS2) 0331 includes a message header (HS2) 0332, a data transfer request message digest value 0333, and a standard format message digest value 0334.
In addition, the signature request message (MS2) 0331 is assigned a communication agent electronic signature 0335.
As the data transfer request message digest value 0333, the digest value (dig (MS1)) calculated in step 1414 is set.
As the standard format message digest value 0334, the digest value (dig (Mα)) calculated in step 1415 is set.
In each field of the message header (HS2) 0332, a fixed value “signature request” is set in the message type field 1001, and the message header (HS1) of the data transfer request message (MS1) 0311 received in step 1411 is set for the other fields. ) Set the same value as each corresponding field of 0312.
[0023]
(Step 1417): The message transfer control unit 0216 calls the communication processing unit 0211 and transmits the signature request message 0331 to the communication entrustor computer 0112.
(Step 1453): In the communication entrustor computer 0112, the communication processing unit 0211 receives the signature request message 0331 and passes it to the communication entrustment control unit 0217.
The communication entrustment control unit 0217 analyzes the signature request message (MS2) 0331 received by calling the unique format message processing unit 0213, and analyzes the message header (HS2) 0332, the data transfer request message digest value 0333, and the standard format message digest value 0334. To get.
Here, the communication request source computer determines the message type from the message type field 1001 in the message header (HS2) 0332 and confirms that it is “signature request”.
(Step 1454): The communication delegation control unit 0217 calls the proper format message processing unit 0213, and uses the communication agent electronic signature 0335 given to the signature request message (MS2) 0331 received in Step 1453, for the communication agent Z. Verification is performed using the public key PZ0002.
That is, the communication agent electronic signature value 0336 is decrypted with the public key PZ0002 of the communication agent Z, and compared with the digest value of the signature request message (MS2) 0331 recalculated on the communication entrustor computer side.
At this time, the unique format message processing unit 0213 can perform the digest value calculation of each data and the calculation of decryption of the electronic signature value based on a general encryption algorithm by calling the signature generation / verification processing unit 0212. I can do it.
The public key PZ0002 of the communication agent Z is stored in the key information table 0801 of the communication entrustor computer 0112.
[0024]
(Step 1455) The communication entrustment control unit 0217 calls the specific format message processing unit 0213, and calculates the digest value of the data transfer request message (MS1) 0311 transmitted in Step 1452.
Further, the obtained digest value is compared with the data transfer request message digest value 0333 stored in the signature request message (MS2) 0331 received in step 1453.
(Step 1456): The communication entrustment control unit 0217 calls the signature generation / verification processing unit 0212 and calculates the electronic signature value of the transfer format message (Mα) 0321.
The electronic signature value is obtained by encrypting the standard format message digest value 0334 stored in the signature request message (MS2) 0331 received in step 1453 with the secret key SA0011 of the communication consignor A.
The secret key SA0011 of the communication entrustor A is stored in the key information table 0801 of the communication entrustor computer 0112.
(Step 1457): The communication entrustment control unit 0217 calls the unique message processing unit 0213 to generate a signature data message (MS3) 0341.
[0025]
FIG. 11 shows the structure of the signature data message (MS3) 0341.
The signature data message (MS3) 0341 includes a message header (HS3) 0342 and a communication entrustor electronic signature value 0343.
The communication entrustor electronic signature value 0343 is the electronic signature value of the transfer format message (Mα) 0321 generated in step 1456.
In each field of the message header (HS3) 0342, a fixed value “signature data” is set in the message type field 1101, and the other message fields of the signature request message (MS2) 0331 received in step 1453 ( HS2) Takes on the same value as each corresponding field of 0332.
[0026]
(Step 1458): The communication entrustment control unit 0217 stores the unique format messages of the data transfer request message 0311, the signature request message 0331, and the signature data message 0341 in the corresponding columns of the transfer data information table 0501.
Here, “0001” is set in the transfer identifier column 0511, “B” is set in the communication destination identifier column 0512, and “transmission” is set in the transmission / reception type column 0513 as values of other columns.
(Step 1459): The communication entrustment control unit 0217 calls the communication processing unit 0211 and transmits the signature data message 0341 created in step 1457 to the communication proxy server 0111.
[0027]
(Step 1418): In communication proxy server 0111, communication processing unit 0212 receives signature data message 0341 and passes it to message transfer control unit 0216.
The message transfer control unit 0216 calls the unique format message processing unit 0213, analyzes the received signature data message 0341, and acquires the message header (HS3) 0342 and the communication entrustor electronic signature value 0343.
Here, the message transfer control unit 0216 determines the message type from the message type field 1101 in the message header (HS3) 0342 and confirms that it is “signature data”.
(Step 1419): The message transfer control unit 0216 calls the standard format message processing unit 0214 (α format message processing unit 0215), and uses the communication entrustor electronic signature value 0343 acquired in Step 1418 to generate the standard format message (Mα ) The sender electronic signature 1313 is assigned to 0321.
(Step 1420): The standard format message with a title (Mα) 0351 to which the sender's electronic signature is assigned in Step 1419 is stored in the standard format message column 0615 of the transfer message information table.
Here, the value of each column is “0001” in the transfer identifier column 0611, “A” in the communication entrustor identifier column 0612, “B” in the communication destination identifier column 0613, and “transmission” in the transmission / reception type column 0614. Value is set.
(Step 1421): Finally, the message transfer control unit 0216 calls the communication processing unit 0211, and transmits the standard name message with a title (Mα) 0351 created in Step 1419 to the communication destination computer 0113.
[0028]
Next, a processing procedure when transferring exchange data received from the communication destination computer from the communication proxy server 0111 to the communication entrustor computer 0112 will be described with reference to FIGS.
FIG. 15 is a flowchart showing a processing procedure in each computer.
A portion (1501) surrounded by a broken line on the left side shows processing steps executed by the communication proxy server 0111, and a portion (1502) surrounded by a broken line on the right side shows processing steps executed by the communication entrustor computer 0112. Yes.
FIG. 4 is a data flow diagram showing the flow of data between the computers.
[0029]
(Step 1511): In communication proxy server 0111, communication processing unit 0211 receives standard format message (Mα) 0401 from destination computer 0113 and passes it to message transfer control unit 0216.
The message transfer control unit 0216 calls the standard format message processing unit 0214 (α format message processing unit 0215), analyzes the received standard format message (Mα) 0401, and transmits a message header (Hα) 0402 and exchange data (D) 0403. To get.
Here, it is assumed that the value of each field of the message header (Hα) 0402 is “0002” for the exchange identifier 1321, “B” for the sender identifier 1322, and “A” for the receiver identifier 1323. .
[0030]
(Step 1512): The message transfer control unit 0216 identifies the company identifier of the communication destination from the sender identifier 1322 in the message header (Hα) 0402 (here, “B”), and the public key column of the key information table 0801 The public key of the communication destination is acquired from 0812 (here, PB0031).
Further, the message transfer control unit 0216 calls the standard format message processing unit 0214 (α format message processing unit 0215), and verifies the sender electronic signature 0404 (1313) using the acquired public key PB0031.
(Step 1513): The message transfer control unit 0216 calls the proper format message processing unit 0213 to create a received data transfer message (MS4) 0411.
Further, the communication agent electronic signature 0413 is assigned to the received data transfer message (MS4) 0411 using the secret key of the communication agent (here, Z).
[0031]
FIG. 12 shows the structure of the received data transfer message (MS4) 0411.
The received data transfer message (MS4) 0411 includes a message header (HS4) 0412, exchange data (D) 0403, and a standard format message (Mα) 0401.
The received data transfer message (MS4) 0411 is given a communication agent electronic signature 0413.
Here, exchange data (D) 0403 is the exchange data acquired in step 1512.
The standard format message (Mα) 0401 is the standard format message (Mα) received in step 1511.
In each field of the message header (HS4) 0412, a fixed value “reception data transfer” is set in the message type field 1201.
Other fields are set as follows according to the values of the fields of the message header (Hα) 0402 of the standard format message (Mα) 0401.
First, the company identifier acquired from the receiver identifier field 1323 is set in the communication entrustor identifier field 1202.
In the communication destination identifier field 1204, the company identifier acquired from the sender identifier field 1322 is set.
Finally, the value acquired from the exchange identifier field 1321 is set in the transfer identifier field 1203.
Here, “A” is set in the communication entrustor identifier field 1202, “B” is set in the communication destination identifier field 1204, and “0002” is set in the transfer identifier field 1203.
[0032]
(Step 1514): The standard format message (Mα) 0401 received in Step 1511 is stored in the standard format message column 0615 of the transfer message information table 0601.
Here, the transfer identifier column 0611 is “0002”, the communication request source identifier column 0612 is “A”, the communication destination identifier column 0613 is “B”, and the transmission / reception type column 0614 is “reception”. Value is set.
(Step 1515): The message transfer control unit 0216 uses the communication processing unit 0211 to transmit the received data transfer message (MS4) 0411 to the communication entrustor computer 0112.
[0033]
(Step 1551): In communication consignor computer 0112, communication processing unit 0211 receives received data transfer message (MS4) 0411 and passes it to communication consignment control unit 0217.
The communication entrustment control unit 0217 analyzes the received data transfer message (MS4) 0411 received by calling the unique format message processing unit 0213, and determines the message header (HS4) 0412, the exchange data (D) 0403, and the standard format message (Mα ) 0401 is acquired.
Here, the communication entrustor computer 0112 acquires the message type from the message type field 1201 in the message header (HS4) 0412 and confirms that it is “transfer received data”.
[0034]
(Step 1552): The communication entrustment control unit 0217 calls the proper format message processing unit 0213, and uses the communication agent electronic signature 0413 attached to the received data transfer message (MS4) 0411 received in Step 1551 as the communication agent Z. The public key PZ0002 is verified.
That is, the communication agent electronic signature value 0414 is decrypted with the public key PZ0002 of the communication agent Z and compared with the digest value of the received data transfer message (MS4) 0411 recalculated on the communication entrustor computer side.
At this time, the unique format message processing unit 0213 can perform the digest value calculation of each data and the calculation of decryption of the electronic signature value based on a general encryption algorithm by calling the signature generation / verification processing unit 0212. I can do it.
The public key PZ0002 of the communication agent Z is stored in the key information table 0801 of the communication entrustor computer 0112.
[0035]
(Step 1553): The communication entrustment control unit 0217 stores the received data transfer message (MS4) 0411 in each corresponding column of the transfer data information table 0501. Here, the received data transfer message (MS4) 0411 is stored in the received data transfer message (MS4) when, for example, some trouble occurs between the communication consignor and the communication agent. Used to prove that it has been received.
Here, “0002” is set in the transfer identifier column 0511, “B” is set in the communication destination identifier column 0512, and “transmission” is set in the transmission / reception type column 0513 as values of other columns.
(Step 1554): The communication entrustment control unit 0217 delivers the exchange data (D) 0403 acquired in Step 1551 to the business processing unit.
Next, an example of a digest value calculation method and an electronic signature addition method for a message will be described with reference to FIG.
[0036]
FIG. 16 is an example in which the format is described more specifically using the standard format message (Mα) 1301 as an example.
In this format example, the standard format message (Mα) 1301 is packaged in the MIME format (see Non-Patent Document 6 described above).
A line indicated by a symbol 1621 indicates that the entire package is in a MIME format including a plurality of parts, and each part is delimited by a boundary character string “--boundary”.
The line indicated by the symbol 1622 indicates a boundary character string that divides each part.
The lines indicated by the symbols 1623 and 1624 are the header lines of each part, the line 1623 is a content type (Content-Type) of the part, and the line 1624 is a content identifier (Content-ID) uniquely indicating the content in the package. Show.
For example, the content type of the message header 1311 is “application / octet-stream”, and the content identifier is “header”.
In the last part, a sender electronic signature 1313 is expressed and stored in the form of an XML electronic signature.
A line indicated by a symbol 1631 indicates that the XML document is an XML digital signature (Signature element).
[0037]
A portion surrounded by a frame line indicated by a symbol 1614 represents electronic signature information, and includes reference information (Reference element) for each part to be included in the signature target.
Each reference information (a portion surrounded by a frame line indicated by symbols 1615 and 1616) includes a digest value for the reference destination data.
Incidentally, the digest value for the message header 1311 is stored in the part surrounded by the frame line indicated by the symbol 1615, and the digest value for the exchange data 1312 is stored in the part surrounded by the frame line indicated by the symbol 1616. .
The row indicated by the symbol 1633 designates the content identifier of the part to be included in the signature target. The row indicated by the symbol 1634 specifies the algorithm used in calculating the digest value.
Here, the SHA-1 algorithm is used.
The row indicated by the symbol 1635 stores the digest value calculated by the algorithm shown in the row 1644 for the part referenced by the row 1633.
Thus, the electronic signature information 1614 (the part surrounded by the frame line indicated by the symbol 1614) includes the digest values of the message header 1311 and the exchange data 1312.
Therefore, by further calculating the digest value for the electronic signature information 1614, the digest value for the standard format message (Mα) 1301 is calculated.
[0038]
In the row indicated by the symbol 1632, a set of an algorithm for calculating a digest value for the electronic signature information 1614 and an encryption algorithm for generating an electronic signature value for the obtained digest value are designated.
Here, SHA-1 is designated as the digest value calculation algorithm, and DSA is designated as the encryption algorithm.
That is, the digest value calculated by the SHA-1 algorithm for the electronic signature information 1614 becomes the digest value (dig (Mα)) for the standard format message (Mα) 1301, and the DSA algorithm is used for the obtained digest value. The result is an electronic signature value (sender electronic signature value 1314) for the standard format message (Mα) 1301 (sgn (x, Mα), where x represents the sender).
Sender electronic signature value 1314 is stored in the row indicated by symbol 1636.
Here, the digest value for the standard format message (Mα) 1301 is the same regardless of whether or not the sender electronic signature 1313 is set to the standard format message (Mα) 1301.
[0039]
As described above, the present invention enables the following.
First, according to the present invention, for a standard format message transferred by a communication agent to a communication destination at the request of the communication agent, the communication agent does not entrust a secret key to the communication agent. You can give an electronic signature.
As a result, the communication consignor can avoid the risk of consigning a private key (corresponding to the company's own seal) to a third party communication agent, and also for the communication agent, security against the private key of the communication consignor. The above management risk can be avoided.
The communication destination can transparently exchange data with the communication consignor without being aware of the communication agent.
[0040]
Secondly, by assigning an electronic signature of the communication agent to the signature request message, it is possible to prevent the communication consignor from giving an electronic signature to a standard format message or arbitrary data with inappropriate contents. Thus, a digital signature can be securely attached to a standard format message to be transferred.
For example, when a problem occurs, the scope of responsibility can be clarified between the communication agent and the communication consignor as follows.
When a standard format message with an inappropriate content to which the electronic signature of the communication consignor is attached is found, the communication consignor searches for the corresponding signature request message from the past history data stored in the transfer data management table.
This may be done by searching for a signature request message including a digest value for a standard format message with inappropriate content.
If the corresponding signature request message exists, it means that the communication agent has made an illegal signature request, and the communication requester denies the signature request message because the electronic signature of the communication agent is given to the signature request message. I can't do anything.
On the other hand, if the corresponding signature request message does not exist, there is no fact that the communication agent made an illegal signature request, and the communication requesting party managing the private key that generated the electronic signature in question is responsible. It will be.
[0041]
Thirdly, by including the digest value of the data transfer request message in the signature request message, it is possible to confirm to which data transfer request the signature request by the communication agent was made. Become.
When a problem such as finding a standard format message with an illegal content to which an electronic signature of the transfer consignment source is found, the transfer consignment source indicates a pair of a data transfer request message transmitted by itself and a signature request message corresponding thereto.
Thereby, it can be confirmed later whether or not the data transfer request message itself has an error.
Furthermore, even if the communication agent erroneously transmits a signature request message in response to an illegal data transfer request message, it is not unfairly liable.
[0042]
Fourth, the signer of the electronic signature added to the standard format message transmitted to the communication destination can be changed dynamically and flexibly by the communication entrustor computer.
For example, in inter-company electronic commerce, the person in charge who needs to give an electronic signature may differ depending on the contents of exchange data.
If these switching operations are performed by the communication proxy server, the processing of the communication proxy server may be complicated.
[0043]
Fifth, by assigning the electronic signature of the communication agent to the received data transfer message, it is possible to guarantee the transfer contents of the standard format message received by the communication agent server to the communication entrustor computer.
That is, the communication consignor can obtain a guarantee about the verification fact of the communication agent for the electronic signature of the communication destination given to the standard format message and the contents of the exchange data transferred.
[0044]
Finally, the present invention is a technique that can be generally applied not only to a communication agency service business in an inter-enterprise electronic commerce but also to data exchange via a communications agency server.
[0045]
【The invention's effect】
As described above, according to the present invention, the communication consignor can safely communicate with the communication consignor for the standard format message transferred by the communication consignor without consigning his / her private key to the communication agent. An electronic signature can be given.
[Brief description of the drawings]
FIG. 1 is a first diagram showing a system configuration in an embodiment of the present invention.
FIG. 2 is a second diagram showing a system configuration in an embodiment of the present invention.
FIG. 3 is a diagram showing a data flow during transmission of exchange data in an embodiment of the present invention.
FIG. 4 is a diagram showing a data flow when receiving exchange data in one embodiment of the present invention.
FIG. 5 is a diagram showing the structure of a transfer data information table in an embodiment of the present invention.
FIG. 6 is a diagram showing a structure of a transfer message information table in an embodiment of the present invention.
FIG. 7 is a diagram showing the structure of a communication entrustor management information table in an embodiment of the present invention.
FIG. 8 is a diagram showing the structure of a key information table in an embodiment of the present invention.
FIG. 9 is a diagram showing the structure of a data transfer request message in an embodiment of the present invention.
FIG. 10 is a diagram showing the structure of a signature request message in one embodiment of the present invention.
FIG. 11 is a diagram showing a structure of a signature data message in an embodiment of the present invention.
FIG. 12 is a diagram showing the structure of a received data transfer message in an embodiment of the present invention.
FIG. 13 is a diagram showing the structure of a standard format message in one embodiment of the present invention.
FIG. 14 is a diagram showing a flowchart of processing when exchange data is transmitted in an embodiment of the present invention.
FIG. 15 is a diagram showing a flowchart of processing when receiving exchange data in an embodiment of the present invention.
FIG. 16 is a diagram showing a method for assigning an electronic signature to a standard format message in an embodiment of the present invention.
FIG. 17 is a diagram showing a schematic configuration of an example given for explaining the outline of the present invention.
[Explanation of symbols]
0101 Communications agent
0102 Communication consignor
0103, 0104 Communication destination
0111 Communication agent server (Communication agent computer)
[0112] Communication consignor computer
0113, 0114 Destination computer
0211 Communication processing unit
0212 Signature generation / verification processor
0213 Proprietary format message processing section
0214 Standard format message processor
0216 Message transfer control unit
0217 Communication commission control unit
0218 Business Processing Department

Claims (6)

In a data exchange system in which a communication consignor computer connected to a communication network via a communication agent computer and a communication destination computer relay data to each other via the communication agent computer, the communication consignor computer and the communication agent The message format including the exchange data used when exchanging exchange data with the computer is the first format, and the exchange data used when exchanging exchange data between the communication agent computer and the communication destination computer is The message format including the second format
When the exchange data transmitted as a message in the first format from the communication consignor computer to the communication agent computer is converted into a second format message in the communication agent computer and transmitted to the communication destination computer, the second format A signature generation method for attaching an electronic signature of a communication consignor based on public key cryptography to the message of
A first step of obtaining a digest value for the second type message in the communication agent computer; a second step of transmitting a signature request message including the digest value to the communication entrustor computer;
A third step of encrypting the digest value with the secret key of the communication consignor and obtaining an electronic signature value for the message in the second format in the communication consignor computer, and including the electronic signature value A fourth step of sending the signature data message to the communication agent computer;
And a fifth step of assigning a communication consignor's electronic signature to the message in the second format using the electronic signature value in a communication agent computer. The signature generation method according to claim 1,
A signature generation method comprising: attaching a digital signature of a communication agent to a signature request message before transmitting the signature request message to a communication consignor in the second step. The signature generation method according to claim 2,
The communication agent computer obtains a digest value for the received first format message, and includes the digest value in the signature request message. The communication entrustor computer connected to the communication network via the communication agent computer and the communication destination computer relay the data on the communication agent computer and exchange data with each other, and between the communication agent computer and the communication agent computer The message format including the exchange data used when transmitting / receiving exchange data in the first format is the first format, and the message format including the exchange data used when transmitting / receiving exchange data between the communication agent computer and the communication destination computer is The second form,
When the exchange data transmitted as a message in the first format from the communication consignor computer to the communication agent computer is converted into a second format message in the communication agent computer and transmitted to the communication destination computer, the second format A data exchange system for attaching a digital signature of a communication consignor based on public key cryptography to the message of
The communication agent computer has means for obtaining a digest value for the message of the second format, and means for transmitting a signature request message including the digest value to the communication consignor computer,
The communication entrustor computer encrypts the digest value with the secret key of the communication entrustor, obtains an electronic signature value for the second format message, and a signature data message including the electronic signature value. A means for transmitting to the communication agent computer;
A data exchange system, characterized in that the communication agent computer has means for attaching the electronic signature of the communication consignor to the message in the second format using the electronic signature value. The data exchange system according to claim 4, wherein
The communication agent computer has means for giving an electronic signature of the communication agent to the signature request message before transmitting the signature request message to the communication consignor. The data exchange system according to claim 5, wherein
The data exchange system includes a means for obtaining a digest value for the received first type message and including the digest value in the signature request message.

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