JP2003309557A - Electronic signature method - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To reduce the communication time required for digitally signing a message used in electronic commerce performed through a center. A terminal causes a center to create a transmission message. The center 10 stores the created transmission message, and when receiving the electronic signature command, creates a summary of the message and transmits only the summary to the terminal 20. The terminal 20 digitally signs the received summary and sends it back to the center 10 together with the digital certificate. The center 10 adds a digital signature and a digital certificate from the terminal 20 to the transmission message to create a transmission message with an electronic signature.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic signature method, and more particularly to an electronic signature method used in a commercial transaction performed via an electronic commercial transaction apparatus (center) existing on a network.

[0002]

2. Description of the Related Art In electronic commerce carried out via a network such as the Internet, it is essential for a recipient to perform authentication for confirming the validity of a message received via the network.

Generally, in the above-mentioned authentication, a private key known only to the sender, a public key forming a pair with this private key, and an electronic certificate issued by a certificate authority which is a third party (public key certification). Calligraphy) and. The authentication method will be briefly described below.

In advance, sender A creates a private key and a public key paired with it. Then, the sender A stores the private key, while sending the public key to the certificate authority via the network to apply for issuance of the electronic certificate. The certificate authority issues a digital certificate including predetermined information about the sender A, an encryption method, a public key of the sender A, an expiration date, and certificate of the certificate authority. The sender A receives the electronic certificate issued by the certificate authority via the network.

When the sender A sends a message, the sender A encrypts the message using his / her private key. And sender A
Combines the encrypted electronic text with the electronic certificate to form a signed electronic text, which is sent to the recipient B via the network.

When the receiver B receives the electronic message with the signature from the sender A, the receiver B requests the certificate authority to provide the certificate of the certificate authority. Recipient B, upon obtaining the certificate of the certificate authority, compares it with the certificate information of the certificate authority included in the electronic certificate sent from sender A. If the certificate authority certificate information of the electronic certificate and the content of the certificate of the certificate authority match, the recipient B regards the electronic certificate as a valid one issued by the certificate authority, and It is assumed that the public key included in the digital certificate belongs to sender A.

Recipient B uses the public key of sender A extracted from the electronic certificate to decrypt the encrypted electronic message included in the received electronic message with a signature. At this time, if the encrypted message is a legitimate one encrypted with the secret key of the sender A, it can be decrypted with the common key of the sender A, but if it is improper, it cannot be decrypted correctly. . Therefore, it is possible to determine that the encrypted telegram that could be decrypted using the public key of the sender A was sent from the sender A.

In the above description, the case where the electronic message itself is encrypted and transmitted is described, but the electronic message remains as plain text and its summary (message digest: a result obtained by performing a specific arithmetic process on the electronic message) Therefore, it is possible to detect tampering with a telegram.) Is often encrypted. This is because the process can be simplified by encrypting / decrypting the abstract rather than encrypting / decrypting the message itself.

In the above description, the sender A and the sender B have been described to perform encryption and decryption, respectively. However, in reality, an authentication program incorporated in a web browser or an electronic mail program is used. , Run automatically.

In the above description, the case of directly transmitting a message from the sender A to the recipient B has been described. However, in actual electronic commerce, an intermediary may exist between the sender and the recipient. is there. For example, in an Internet auction or the like, there are cases where the organizer employs a system that mediates between the seller and the purchaser in order to guarantee the safety of the transaction.

Conventionally, transmission of a telegram relating to a commercial transaction performed through an intermediary (electronic commerce center, hereinafter simply referred to as center) is performed as follows.

First, the sender A creates a message to be sent to the recipient B by using the input format provided by the center. That is, the sender sends the information necessary for creating the electronic message to the center, and the center creates the electronic message including the received information. Then, the center stores the created electronic message in the storage unit and transmits it to the sender.

The sender electronically signs the electronic message sent from the center. That is, the sender creates a summary of the received electronic message, encrypts the created abstract with his / her own private key to obtain a digital signature, and combines the electronic signature with the received electronic message. The sender further combines the received electronic message and electronic signature with an electronic certificate, and sends it back to the center as a signed electronic message.

The center transmits the received electronic message with signature to the recipient designated by the sender.

The receiver authenticates the received electronic message in the same manner as described above.

[0016]

In electronic commerce conducted through the electronic commerce center, a message is sent from the center to the sender, and then a message with a signature is sent from the sender to the center. For this reason, the larger the size of the message, the longer the communication time required for the electronic signature.

An object of the present invention is to provide an electronic signature method capable of reducing the communication time required for an electronic signature without lowering the security level in the electronic commerce performed through the electronic commerce center.

[0018]

According to the present invention, in a digital signature method used for electronic commerce performed by mediation of an electronic commerce device existing on a network, a sender is a terminal device connected to the network. Using the above, the electronic commerce device is made to create a transmission message specifying a recipient, the electronic commerce device stores the created transmission message in a storage unit, and receives an electronic signature command for the transmission message from the terminal device. When the transmission electronic message is read from the storage unit, a summary of the transmission electronic message is created and transmitted to the terminal device, the terminal device transmits the electronic signature command to the electronic commerce device, and then, from the electronic commerce device. When the summary is received, the summary is encrypted using a secret key stored in advance to obtain a digital signature, and the digital signature and the signature stored in advance are stored. A certificate and the electronic commerce device, and the electronic commerce device receives the electronic signature and the electronic certificate from the terminal device, adds the electronic signature and the electronic certificate to the transmission message, and electronically An electronic signature method is obtained which is characterized by creating a transmission message with a signature.

Further, according to the present invention, a program installed in a web browser operating on a computer, having a function of causing an electronic commerce device connected via a network to create a transmission message, and the electronic commerce device A function for issuing an electronic signature command to the electronic commerce device, and a summary of the transmission message is sent from the electronic commerce device,
A function of encrypting the abstract using a secret key stored in advance to generate a digital signature, and a function of transmitting the digital signature and a digital certificate stored in advance to the electronic commerce device. A program for achieving it is obtained.

Further, according to the present invention, there is provided a telegram creating program which operates on a computer for realizing electronic transactions, and has a function of creating a transmission telegram based on an instruction from a terminal device and storing it in a storage unit. A function of receiving the electronic signature command from the terminal device, reading the transmission message from the storage unit to create a summary thereof, and transmitting the summary to the terminal device; and a digital signature transmitted from the terminal device. And a message creating program for realizing a function of adding an electronic certificate to the transmission message and creating a transmission message with an electronic signature is obtained.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings.

Referring to FIG. 1, an electronic commerce system to which an electronic authentication method according to an embodiment of the present invention is applied includes an electronic commerce device (center) 10 provided on a communication network (Internet) 100. It has a plurality of trader terminals 20 and 30 connected to the center 10 via a communication network 100.

The center 10 is constituted by an information processing device (computer) such as a workstation and a server, and realizes electronic commerce between the trader terminals 20 and 30. Specifically, the center 10 manages the login names and passwords of the trader terminals 20 and 30 that are allowed to participate in the commercial transaction group, and determines whether the login to the center 10 is permitted or not permitted. Also, center 1
0 creates a telegram to be transmitted to the receiving side trader terminal according to the instruction from the transmitting side trader terminal. In addition, when the center 10 receives the electronic signature command from the sending side trader terminal, it creates a summary of the created electronic message and sends it to the sending side trader terminal. Further, the center 10 combines the electronic signature and the electronic certificate transmitted from the sender's terminal with the created electronic message to create a signed electronic message and stores the created electronic message with a signature, or the transaction on the receiving side. Send to the vendor terminal. The functions of creating a message, a summary, and a message with a signature in the center 10 are realized by a message creating program running on the center 10. The electronic message creating program includes a center digital signature program that cooperates with a terminal digital signature program described later.

Each of the trader terminals 20 and 30 is an information processing device such as a personal computer. Trader terminal 2
0 and 30 can access the center 10 via the communication network 100. In addition, each of the trader terminals 20 and 30 can acquire and store the electronic certificate and can electronically sign the abstract transmitted from the center. These functions are provided by each trader terminal 20, 30.
It is realized by a digital signature program for a terminal incorporated in a web browser that operates above.

The electronic authentication method according to this embodiment, which is executed in the electronic commerce system shown in FIG. 1, will be described below with reference to FIG.

The center 10 stores in advance the login names and passwords of the trader terminals 20 and 30 that have joined the electronic commerce group. Further, each of the trader terminals 20 and 30 stores in advance a private key of itself and an electronic certificate that certifies a public key forming a pair with the private key.

The user of the transaction terminal 20 on the transmitting side accesses the center 10 via the communication network 100 using a web browser operating on the transaction terminal 20.

The center 10 requests a login name and password in order to confirm that the trading terminal 20 that has been accessed is a subscriber to the electronic commerce group.
When the login name and the password are transmitted from the trader terminal 20, the center 10 determines whether the trader terminal 20 is a subscriber. Then, when the trader terminal 20 determines that it is a subscriber, the center 10 causes the web browser to display a document form for conducting electronic commerce.

The user of the trader terminal 20 inputs a telegram to be transmitted, destination information of the transaction partner on the receiving side, and the like using a web browser. Then, when the user clicks the button for instructing the message creation, the information necessary for the message creation is sent from the trader terminal 20 to the center 10.

The center 10, which has received the information necessary for creating the electronic message, creates a transmission electronic message X using the received information and stores it in a storage unit (not shown).

Next, the user of the trader terminal 20 clicks the electronic signature command button on the web browser to instruct the center 10 to execute an electronic signature. The electronic signature program A-1 of the center 10 which has received the execution instruction of the electronic signature performs a predetermined calculation process on the stored transmission electronic message X to create a summary (message digest) X-1. 20 to the electronic signature program A-2.

The electronic signature program A-2 for the terminal operating on the trader terminal 20 stores the summary X-1 in advance when the summary X-1 of the transmission message is sent from the center 10. An electronic signature Y is created by encryption using the private key. Further, the terminal electronic signature program transmits the created electronic signature Y and the electronic certificate stored in advance to the center 10.

Digital signature program A-1 of the center 10
Creates (adds (combines)) the received electronic signature Y and electronic certificate to the stored electronic message X to create a transmission electronic message Z with an electronic signature. Then, the electronic signature program A-1 stores the created electronic message with electronic signature Z in the storage unit. After this, when the center 10 receives another transmission command for the electronic signature-attached transmission message Z from the trader terminal 20, the center 10 reads the electronic signature-attached transmission message Z from the storage unit and transmits it to the trader terminal 30. Alternatively, when the center 10 receives a command from the trader terminal 30 to transmit a message addressed to itself, the center 10 reads out the transmission message Z with electronic signature from the storage unit and transmits it to the trader terminal 30.

The trader terminal 30 performs the authentication operation of the transmission message Z with the electronic signature transmitted from the center 10.

The trader terminal 20 in the above description
Among the operations of the above, the reception of the abstract, the encryption of the abstract, the transmission of the electronic signature and the electronic certificate are automatically executed by the electronic signature program for the terminal, and therefore, the user has the terminal 2 of the trader.
It is not necessary to manipulate 0.

Among the operations in the electronic commerce device,
After receiving the electronic signature command, read the transmission message from the storage unit, create a summary and send it to the trader terminal, receive the electronic signature and electronic certificate from the terminal device, and create the transmission message with the electronic signature. , Is automatically executed by an electronic signature program for an electronic commerce device.

As described above, according to the present embodiment, only the summary X-1 of the message X to be transmitted is sent to the center 10.
From sending to the sending side trader terminal 20,
An electronic signature on the electronic message X to be transmitted without transmitting the electronic message X to be transmitted from the center 10 to the transmitting side transaction terminal 20 and without transmitting an electronic message with an electronic signature Z from the transmitting side transaction terminal 20 to the center 10. Can be executed. As a result, the communication time required for the digital signature can be significantly reduced, and the convenience of the user is greatly improved. This is particularly noticeable in the case of adding a related document or the like to a transmission electronic message and transmitting it.

Further, according to the present embodiment, the center 1
In order to prevent the transmission of the electronic message X from 0 to the transmitting side trader terminal 20, the method of transmitting the secret key of the transmitting side trader terminal 20 to the center 10 is not adopted. It can be kept the same as before.

Although the electronic signature method according to one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment. For example, in the above embodiment, when the center receives a transmission command from the sender or receiver transaction terminal, it sends the electronic signature-added message to the receiver transaction terminal. You may make it transmit immediately after creating a message.

[0040]

As described above, according to the present invention, only the summary of the electronic message is transmitted from the intermediary to the sender, and it is not necessary to transmit the electronic message itself. Therefore, it is not necessary to transmit the electronic message from the sender to the intermediary. The communication time required for the electronic signature can be significantly reduced without lowering the security level.

[Brief description of drawings]

FIG. 1 is a configuration diagram of an electronic commerce system to which an electronic signature method of the present invention is applied.

FIG. 2 is a diagram illustrating an electronic signature method to which an electronic signature method according to an exemplary embodiment of the present invention is applied.

[Explanation of symbols]

10 Center 20,30 Trading terminal 100 communication network (Internet)

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI Theme Coat (reference) G06F 17/60 ZEC H04L 9/00 675B 675Z (71) Applicant 302060926 Fujita, Tokyo Shigaya-ku 4-chome 25-2 (72) Inventor Haruhiko Yamazaki 1-18-6 Shinkiba, Koto-ku, Tokyo N.C. Soft Co., Ltd. (72) Inventor Junichi Yamashita 4-25-2 Sendagaya, Shibuya-ku, Tokyo Fujita Co., Ltd. In the business system (72) Inventor Toshinori Tamaki 4-25-2 Sendagaya, Shibuya-ku, Tokyo Fujita Co., Ltd. (72) Inventor Hiroshi Koki, 16-1 Yatsu, Narashino, Chiba Prefecture Core Systems Co., Ltd. F term in design (reference) 5B085 AA08 AE15 AE29 BA07 BG01 5J104 AA09 LA06 MA01 PA07 PA10

Claims (7)

[Claims] 1. A digital signature method used for electronic commerce performed by intermediary of an electronic commerce device existing on a network, wherein a sender receives the electronic commerce device by using a terminal device connected to the network. The electronic commerce device stores the created transmission message in a storage unit, and when receiving an electronic signature command for the transmission message from the terminal device, transmits the transmission message from the storage unit. When a summary is read from the electronic message and transmitted to the terminal device, and the terminal device receives the abstract from the electronic commerce device after transmitting the electronic signature command to the electronic commerce device, the terminal device stores it in advance. The abstract is encrypted by using the private key that has been set to form an electronic signature, and the electronic signature and the electronic certificate stored in advance are used in the electronic commerce device. When the electronic commerce device receives the electronic signature and the electronic certificate from the terminal device, the electronic commerce device adds the electronic signature and the electronic certificate to the transmission message to create a transmission message with an electronic signature, An electronic signature method characterized by the above. 2. The electronic signature method according to claim 1, wherein the function of the terminal device is provided by a web browser operating on the terminal device. 3. The electronic signature method according to claim 2, wherein the abstract is received by the terminal device after the electronic signature command is transmitted, the electronic signature is generated by encrypting the abstract, and the electronic signature is generated. An electronic signature method, wherein the electronic signature and the transmission of the electronic certificate to the electronic commerce device are automatically executed by an electronic signature program for a terminal incorporated in the web browser. 4. The electronic signature method according to claim 2, wherein the function of the electronic commerce device is provided by a message creating program which operates on the electronic commerce device and cooperates with the web browser. Characteristic digital signature method. 5. The electronic signature method according to claim 4, wherein the transmission electronic message is read from the storage unit and is transmitted by the electronic commerce device after receiving the electronic signature command from the terminal device. An electronic commercial transaction in which the creation of an electronic message summary and transmission to the terminal device, the reception of the electronic signature and the electronic certificate from the terminal device, and the creation of the electronic message with the electronic signature are incorporated in the electronic message creation program. An electronic signature method, which is automatically executed by an electronic signature program for a device. 6. A program installed in a web browser operating on a computer, the function of causing an electronic commerce device connected via a network to create a transmission message, and an electronic signature command to the electronic commerce device. A function for issuing, when a summary of the transmission message is sent from the electronic commerce device, a function of encrypting the summary using a secret key stored in advance to generate an electronic signature, A program for realizing a function of transmitting an electronic signature and an electronic certificate stored in advance to the electronic commerce device. 7. A telegram creation program that operates on a computer that realizes electronic transactions, and has a function of creating a transmission telegram based on an instruction from a terminal device and storing it in a storage unit. A function of receiving the electronic signature command, reading the transmission message from the storage unit, creating a summary of the transmission message, and transmitting the summary to the terminal device; and an electronic signature and an electronic certificate transmitted from the terminal device, A function to create a transmission message with a digital signature by adding it to a transmission message, and a message generation program that realizes the function.