JP2003309546A - Method for transferring information - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an information transfer method capable of assuring its own authenticity of a computer on the information transmission side and protecting information from an illegal act such as eavesdropping by a third party. <P>SOLUTION: A first computer has steps of 1) obtaining a public key of a second computer from a public key authentication office, 2) encrypting information to be transmitted to the second computer using its own private key, wherein the information has been encrypted using the obtained second public key, 3) transmitting two information, one is the information encrypted by the step 2) and the other is information indicative of the first computer, to the second computer. The second computer has steps of 1) confirming the first computer, 2) obtaining a public key of the first computer from the public key authentication office, 3) decoding the encrypted information by the public key of the first computer and then decoding it by its own private key. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of exchanging information between two computers, and more particularly to a technique effectively applied to a method of exchanging information between two different servers in WWW.

[0002]

2. Description of the Related Art Conventionally, two different servers α and β
Then, the following method is known as a method of transmitting and receiving information by encrypting. In the first method, a common key Kαβ of a common key encryption method used only when information is exchanged between two different servers α and β is determined, X is the information to be exchanged from the server α to the server β, and K to encrypt the information X with the encryption key K in the encryption method of
When described as (X), the server α designates the server β from the server α and the information indicating the server α and the information (Kαβ (X)) obtained by encrypting the information X with the common key Kαβ. By adding it as a parameter of the URL to be transmitted, the server β can confirm the server α of the transmission source from these parameters and the encrypted information K
This is a method of protecting the information X from a fraudulent act of a third party by decrypting αβ (X) with the common key Kαβ.

The second method is to use two different servers α and β, and a public key certification authority CAβ for the server β.
In a system formed by terminals used by service users, the public key given from the public key certification authority CAβ to the server β is Kβp, the secret key is Kβs, and the information to be exchanged from the server α to the server β is X, and K to encrypt the information X with the encryption key K in the encryption method of
When described as (X), the server α has two pieces of information, information indicating the server α and information (Kβp (X)) encrypted with the public key Kβp of the server β obtained from the public key certification authority CAβ. Is added as a parameter of the URL for specifying the server β from the server α, the server β of the sender is confirmed from these parameters in the server β, and the encrypted information Kβp (X) is secret key. K
This is a method of protecting the information X from a fraudulent act of a third party by decrypting it with βs.

The third method is to use two different servers α and β, and a public key certification authority CAα for the server α.
In a system formed by terminals used by service users, a public key given from the public key certification authority CAα to the server α is Kαp, a secret key is Kαs, and information to be exchanged from the server α to the server β is X. K (X) means that the information X is encrypted with the encryption key K in the encryption method of
, The information indicating the server α,
And two pieces of information (Kαs (X)) obtained by encrypting the information X with the secret key Kαs of the server α are added as parameters of the URL that specifies the server β from the server α. From the parameters,
The authenticity of the server α is confirmed by confirming the sender server α and decrypting the encrypted information Kαs (X) with the public key Kαp of the server α obtained from the public key certification authority CAβ. Is the way to do it.

[0005]

However, the above-mentioned first method, that is, the method of using the encryption key of the common key encryption method, creates a new encryption key with the existing server every time a new server is introduced. There was a problem that it was necessary to define. In the second method, which uses the public key of the public key cryptosystem on the side of receiving information, the existing public key certification authority is used, so that the labor for the encryption key can be saved, but unauthorized use such as eavesdropping is prevented. There is a problem that a third party who obtains the information encrypted by various means may impersonate as an appropriate sender. Furthermore, in the third method, which uses the private key of the public key cryptosystem of the information sending side,
By using the existing public key certificate authority, you can save time and effort regarding the encryption key, but a third party who obtains the information encrypted by unauthorized means such as wiretapping can obtain the public key of the sender of the information. By inserting it, there was a possibility that the information would be decrypted.

The present invention has been made in order to solve the above-mentioned problems of the prior art, and an object of the present invention is to ensure the correctness of the information transmitting computer itself in the information transfer method, and It is to provide a technology capable of protecting information from illegal acts such as wiretapping. The above and other objects and novel features of the present invention will become apparent from the description of this specification and the accompanying drawings.

[0007]

Among the inventions disclosed in the present application, a brief description will be given to the outline of typical ones.
It is as follows. That is, the present invention provides an information transmission source computer (α), an information transmission destination computer (β), a public key (Kαp) and a secret key (Kαs) of the information transmission source computer (α), and an information transmission destination computer ( When the information transmission source computer (α) transfers information (X) to and from the information transmission destination computer (β) using the public key (Kβp) and the secret key (Kβs) of β), the information transmission source computer (α) ) Is the information transmission source computer (α), and the information (X) encrypted with the public key (Kβp) and the information encrypted with the private key (Kαs) of the information transmission destination computer (β). ), The information transmission destination computer (β) confirms the information transmission source computer (α), decrypts the encrypted information with the public key (Kαp), and further, its own secret key (Kβ
The information (X) is obtained by decoding with (s).

In the present invention, the information transmission source computer is a WWW portal site server, the information transmission destination computer is an application server, and the portal site server (α) is the portal site server (α). ), And the public key (K
Information (X) encrypted with βp) is stored in the private key (Kα
The information encrypted in s) is added as a parameter of the URL designating the application server (β) from the portal site server (α) and transmitted to the application server (β) by the access from the user terminal. . In the present invention, the information transmitted from the portal site server to the application server is
This is information that identifies the user. According to the above-mentioned means, the legitimacy of the server itself which has sent the information is guaranteed, and the information can be protected from the illegal acts of the third party such as wiretapping.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In all the drawings for explaining the embodiments, the same reference numerals are given to those having the same function, and the repeated description thereof will be omitted. [First Embodiment] FIG. 1 is a diagram showing an information transfer procedure in an information transfer method according to a first embodiment of the present invention. Hereinafter, the information transfer method according to the present embodiment will be described. First, the server α (30) uses the public key certification authority CAβ to obtain the public key of the public key authentication scheme of the server β (40).
The public key request of the server β (40) is made to (60) (step 101). The public key certification authority CAβ (60)
The public key of the server β (40) is passed to the server α (30) (step 102). The server α (30), which has obtained the public key of the server β (40), encrypts the information X using the public key of the server β (40), and further, the server α (3
0) Encryption is performed by the private key of the public key authentication method held by itself (step 103).

The encrypted information includes the URL (Unif indicating the server β (40) together with the information indicating the server α (30).
orm Resource Locators) parameter,
It becomes one of the link destinations in the Web page displayed on the user terminal 20 (step 104). The user 10 clicks the link destination (step 105), and the server β (4
By accessing (0) (step 105), the server β (40) encrypts the information X using the public key of the server β (40) as a URL parameter, and the server α (30) itself retains it. It is possible to obtain two pieces of information, that is, the information encrypted by the secret key of the public key authentication method and the information representing the server α (30). The server β (40) that has obtained this information is the server α that has transmitted the information.
It is confirmed that it is (30) (step 107), and in order to obtain the public key of the public key authentication method of the server α (30)
Public key certificate authority CA α (50) to server α (30)
Requesting the public key (step 108). The public key certificate authority CAα (50) sends the server α to the server β (40).
The public key of (30) is passed (step 109).

The server β (40), which has obtained the public key of the server α (30), decrypts the encrypted information using the public key of the server α (30), and further, the server β (40).
Decryption is carried out by the private key of the public key authentication system held by itself (step 110). The decrypted information becomes the information X itself that the server α (30) intended to send to the server β (40). In the present embodiment, the information X is encrypted by using the public key of the server β (40), and the information encrypted by the secret key of the public key authentication method held by the server α (30) itself. If two pieces of information representing the server α (30) are wiretapped by an unauthorized third party, the server α (30) may be spoofed. To prevent this, the server α (3
0), when encrypting the information X using the public key of the server β (40), encrypts the time at which the information is encrypted, the expiration time of the encrypted data, etc. together with the information X. The server β (4
In 0), it becomes possible to confirm the elapsed time from the encrypted time or the expiration time. In the present embodiment, the public key certification authority CAα (50) of the server 30 and the public key certification authority CAβ of the server 30.
Although the case where two public key certification authorities of (60) are provided has been described, the public key certification authority CAα (50) and the public key certification authority CAβ (60) may be the same public key certification authority. .

[Second Embodiment] In the present embodiment, the server α (30) shown in FIG. 1 is positioned as a portal site for the WWW service so that the user 10 who is authenticated by the portal site server 30 can use it. This is an embodiment in which a service can be received without inputting information for identifying the user 10 to the application server 40 when accessing the possible application server 40. FIG. 2 is a diagram showing an information transfer procedure in the information transfer method according to the second embodiment of the present invention. Less than,
The information transfer method according to the present embodiment will be described. When the user 10 inputs the URL of the portal site server 30 or clicks the link provided for the portal site server 30, the user 10
From the user terminal 20, the portal site server 3
0 is requested (step 111), and as a result, the user terminal 20 accesses the portal site server 30 (step 112). Portal site server 3
0 displays a page for user authentication on the user terminal 20 in order to perform user authentication of the user 10 (step 113).

On the page, the user 10 authenticates the information for identifying the user 10, for example, the user identifier and that the user 10 who uses the user identifier is the correct user 10. Authentication information corresponding to the user authentication required by the portal site server 30, such as information (for example, password), is input (step 11).
4). The authentication information is sent from the user terminal 20 to the portal site server 30 (step 115). The portal site server 30 accesses the user information DB (70) based on the acquired information for identifying the user (step 1
16) Obtain data necessary for user 10 authentication and accessible application server 40 information (step 117). The portal site server 30 authenticates the user 10 from these pieces of information (step 11
8) As a result of the authentication, if it is confirmed that the user 10 is a correct user, the portal site server 30
Requests the public key of the application server 40 to the public key certification authority CAβ (60) in order to obtain the public key of the public key authentication method of the application server 40 that the user 10 can access (step 119).

The public key certificate authority CAβ (60) sends an application server 40 to the portal site server 30.
Pass the public key of (step 120). Portal site server 3 that has obtained the public key of the application server 40
0 uses the public key of the application server 40 to encrypt the information for identifying the user 10, and further encrypts it with the private key of the public key authentication method held by the portal site server 30 itself (step 121). The encrypted information is embedded in the parameter of the URL indicating the application server 40 together with the information indicating the portal site server 30 and displayed on the user terminal 20.
It becomes one of the links in the page (step 12
2). When the user 10 clicks the link destination (step 123) and accesses the application server 40 (step 124), the application server 40 uses the public key of the application server 40 as a parameter of the URL, and the user The information for identifying 10 is encrypted, and further the portal site server 3
It is possible to obtain two pieces of information encrypted by the secret key of the public key authentication scheme held by 0 itself and information representing the portal site server 30.

The application server 40 which has obtained these pieces of information confirms that the server that has transmitted the information is the portal site server 30 (step 125) and obtains the public key of the public key authentication method of the portal site server 30. In order to do so, a public key request for the portal site server 30 is made to the public key certification authority CAα (50) (step 12).
6). The public key certificate authority CAα (50) passes the public key of the portal site server 30 to the application server 40 (step 127). Portal site server 3
The application server 40 that has obtained the public key of 0
The encrypted information is decrypted using the public key of the portal site server 30, and further decrypted by the private key of the public key authentication method held by the application server 40 itself (step 128). The decrypted information serves as information that identifies the user 10 who the portal site server 30 intended to send to the application server 40. Therefore, in the application server 40,
The user 10 does not need to input information for identifying himself again.

In the above embodiment, the public key of the application server 40 is used to encrypt the information for identifying the user 10, and the portal site server 3
When two pieces of information, that is, the information encrypted by the secret key of the public key authentication method held by 0 itself and the information representing the portal site server 30, are intercepted by an unauthorized third party, the information is sent to the portal site server 30. Impersonation may occur. To prevent this, the portal site server 30
When encrypting the information for identifying the user 10 by using the public key of the application server 40, the user 10 specifies the time of encryption or the expiration time of the encrypted data. By encrypting the information together with the information for specifying, the application server 40 that has obtained the information can check the elapsed time from the encrypted time or the expiration time. As described above, the invention made by the present inventor
Although the specific description has been given based on the above-described embodiment, the present invention is not limited to the above-described embodiment, and needless to say, various modifications can be made without departing from the scope of the invention.

[0017]

The effects obtained by the typical ones of the inventions disclosed in the present application will be briefly described as follows. According to the information transfer method of the present invention, the legitimacy of the sending computer itself can be assured and the information can be protected from illegal acts of a third party such as wiretapping.

[Brief description of drawings]

FIG. 1 is a diagram showing an information transfer procedure in an information transfer method according to a first embodiment of the present invention.

FIG. 2 is a diagram showing an information transfer procedure in an information transfer method according to a second embodiment of the present invention.

[Explanation of symbols]

10 ... User, 20 ... User terminal, 30, 40 ... Server, 50, 60 ... Public key certificate authority, 70 ... User information D
B.

Claims (5)

[Claims] 1. A method for exchanging information between a first computer that is an information transmission source and a second computer that is an information transmission destination, wherein the first computer is a public key certificate authority to the second computer. First step of obtaining the public key of the above, and information obtained by encrypting the information to be transmitted to the second computer using the obtained second public key, and further encrypting the information with its own private key. A second step, and a third step of transmitting two pieces of information, the information encrypted in the second step and the information indicating the first computer, to the second computer, The second computer includes a fourth step of confirming the first computer as a computer to which information is transmitted, and a fifth step of acquiring the public key of the first computer from a public key certificate authority. Step a, the encrypted information, decrypted with the public key of the first computer with the acquired further information transfer method characterized by having a sixth step of decoding by a secret key of itself. 2. The second step in the second step
When the information to be transmitted to the computer is encrypted by using the acquired second public key, the information regarding the encrypted time or the period until the information to be transmitted to the second computer is valid The information transfer method according to claim 1, characterized in that the information indicating the is also encrypted together. 3. A first public key certificate authority of a first computer and a second public key certificate authority of a second computer.
One public key certificate authority, the first step is a step of obtaining the public key of the second computer from the second public key certificate authority, and the fifth step is the first step. 3. The method for exchanging information according to claim 1 or 2, further comprising the step of obtaining the public key of the first computer from the public key certification authority of. 4. The first computer is a portal site server in WWW, the second computer is an application server, and the third step includes the information encrypted in the second step. , The information indicating the first computer is added as a parameter of the URL designating the application server from the portal site server, and transmitted to the application server by access from the user terminal. The method of exchanging information according to any one of claims 1 to 3, characterized in that there is. 5. The method of exchanging information according to claim 4, wherein the information transmitted from the portal site server to the application server is information identifying a user.