KR101018924B1 - Data access method in cross-domain, system performing the same and storage medium of storing program for executing the same - Google Patents

Abstract

Disclosed are a data access method on a cross domain using data security level negotiation, a system for performing the same, and a recording medium recording a program for performing the same. A data access method on a cross domain includes (a) normalizing the data security level of the data of the domain and (b) determining whether to allow according to the normalized data security level and user privilege level when accessing the data of the domain. Steps. Therefore, when information is transmitted between domains having different security policies, only information allowed according to the data security level and the user's permission level can be safely transmitted, thereby ensuring compatibility on cross domains.

Cross domain, security level, negotiation, data access, attribute certificate

Description

DATA ACCESS METHOD IN CROSS-DOMAIN, SYSTEM PERFORMING THE SAME AND STORAGE MEDIUM OF STORING PROGRAM FOR EXECUTING THE SAME}

The present invention relates to network security, and more particularly, to a method of accessing data on a cross domain, a system for performing the same, and a recording medium recording a program for performing the same.

As the Internet has become a new medium for smooth communication, the amount of Internet demand by domestic and foreign institutions, companies, and individual users has exploded every year. Recently, the Internet has developed into a combination of a plurality of networks having different access rights or security rights, in addition to the existing client-server communication. In this situation, user access and data transfer between domains of different security levels, that is, cross-domain, are frequently occurring.

In the cross domain, various kinds of information exchange such as personal information, internet page, email, and large files occur. In order to exchange such information, data security level between domains must be negotiated or matched. Therefore, the most important thing in the cross domain is to exchange data according to the security level of the data and the user's permission level. In a dynamic network environment such as a mobile environment or an All IP network environment, it is virtually impossible to negotiate by data.

Conventional information exchange between domains does not provide a general solution in cross domains where domains of various security levels exist. If a trust relationship between domains exchanging information is not established, the ripple effect of network attack is great. Therefore, there is a demand for a method for secure information exchange while maintaining compatibility between domains having different security levels or security policies.

Accordingly, a first object of the present invention is to provide a data access method on a cross domain in which security policies can be compatible with data security grades on different cross domains.

And a second object of the present invention is to provide a data access system for performing the above method.

A third object of the present invention is to provide a recording medium on which a program of instructions that can be executed by a digital processing apparatus that performs the above method is tangibly embodied, and which records a program that can be read by the digital processing apparatus. It is.

A data access method on a cross domain according to an embodiment of the present invention for achieving the first object of the present invention described above comprises the steps of (a) normalizing a data security level of data of a domain and (b) When accessing the data includes determining whether to allow according to the normalized data security level and user privilege level.

In step (a), the data security level may be normalized by using a clustering technique.

In step (a), after k (k is the number of clusters) is agreed between different domains, the data security level may be normalized using a k-means clustering technique.

Step (a) may normalize the data security level in consideration of the domain trust level.

In step (a), the data security level may be normalized based on a product of the data security level and the domain trust level.

The domain trust level may be determined by a Web of Trust technique.

The data security level may include information on at least one of an authentication method, an access authority check level, a key distribution method, and an encryption method required to access data.

In step (b), the attribute certificate may be presented, and whether to permit access to the data of the domain may be determined according to the user right level included in the attribute certificate and the normalized data security level of the data of the domain.

Step (b) controls access to data of the domain by using an attribute certificate including information on a user privilege level, wherein the attribute certificate includes an attribute certificate issuer identifier, an attribute certificate validity period, and a user privilege level. It may include information about.

The data access system on the cross domain according to an embodiment of the present invention for achieving the above-described second object of the present invention, normalizes the data security level of the data of the own domain corresponding to the data security level of the data of the other domain Issuing an attribute certificate to a user or network node of his domain, comparing the attribute certificate presented by the host of the other domain and the normalized data security level of the data of the own domain that the host of the other domain is trying to access Present the property certificate issuer controlling the data access of the host of the other domain and the property certificate issued from the property certificate issuer of the own domain to another domain, and access the data of the other domain according to the user authority level included in the property certificate. It may include a host.

The attribute certificate issuer can normalize the data security level using a clustering technique.

After the attribute certificate issuer agrees k with the attribute certificate issuer of another domain through a certification authority, the data security level can be normalized using a k-means clustering technique.

The issuer of the attribute certificate may normalize the data security level in consideration of the domain trust level.

The attribute certificate issuer may normalize the data security rating based on the product of the data security rating and the domain trust rating.

The attribute certificate issuer may determine the domain trust level using a Web of Trust technique.

The data security level may include information on at least one of an authentication method, an access authority check level, a key distribution method, and an encryption method required to access data.

The attribute certificate may include information about an attribute certificate issuer identifier, an attribute certificate validity period, and a user privilege level.

Data access system on the cross domain according to another embodiment of the present invention for achieving the second object of the present invention described above, the data security level of the data of the own domain corresponding to the data security level of the data of the other domain By normalizing, issuing attribute certificates to users or network nodes in other domains, comparing attribute certificates presented by hosts in other domains with normalized data security levels of data in their domains to which hosts in other domains attempt to access Present the property certificate issuer controlling the data access of the host of the other domain and the property certificate issued from the property certificate issuer of the other domain to another domain, and access the data of the other domain according to the user authority level included in the property certificate. It contains the host.

In order to achieve the above-described third object of the present invention, a program of instructions that can be executed by a digital processing apparatus that performs a data access method on a cross domain according to an embodiment of the present invention is tangibly implemented. The recording medium which records the program which can be read by the processing apparatus includes (a) normalizing the data security level of the data of the domain and (b) normalizing the data security level and the user right when accessing the data of the domain. Record a program that performs the steps of determining acceptance based on the grade.

According to the data access method on the cross-domain as described above, the recording medium recording the system and the program for performing the same, information that is allowed according to the data security level and the authority level of the user when the information transfer between domains with different security policies Only can be transmitted securely, ensuring compatibility on cross domains.

And since the security level can be set dynamically, it is possible to perform secure data transmission through mutual agreement between data and users in a situation where the network security environment such as All IP network environment or mobile environment is dynamically changed.

As the invention allows for various changes and numerous embodiments, particular embodiments will be illustrated in the drawings and described in detail in the written description. However, this is not intended to limit the present invention to specific embodiments, it should be understood to include all modifications, equivalents, and substitutes included in the spirit and scope of the present invention. Like reference numerals are used for like elements in describing each drawing.

The terms first, second, A, B, etc. may be used to describe various elements, but the elements should not be limited by the terms. The terms are used only for the purpose of distinguishing one component from another. For example, without departing from the scope of the present invention, the first component may be referred to as the second component, and similarly, the second component may also be referred to as the first component. The term and / or includes a combination of a plurality of related items or any item of a plurality of related items.

When a component is referred to as being "connected" or "connected" to another component, it may be directly connected to or connected to that other component, but it may be understood that other components may be present in between. Should be. On the other hand, when a component is said to be "directly connected" or "directly connected" to another component, it should be understood that there is no other component in between.

The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting of the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, the terms "comprise" or "have" are intended to indicate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, and one or more other features. It is to be understood that the present invention does not exclude the possibility of the presence or the addition of numbers, steps, operations, components, components, or a combination thereof.

Unless defined otherwise, all terms used herein, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art. Terms such as those defined in the commonly used dictionaries should be construed as having meanings consistent with the meanings in the context of the related art, and, unless expressly defined in this application, are construed in ideal or excessively formal meanings. It doesn't work.

Hereinafter, with reference to the accompanying drawings, it will be described in detail a preferred embodiment of the present invention. Hereinafter, the same reference numerals are used for the same components in the drawings, and duplicate descriptions of the same components are omitted.

Prior to describing an embodiment of the present invention, terms used in the present invention will first be described.

"Data security level" is a value assigned to each data in the domain, and means a result of quantifying the security policy required for access to specific data within the management scope of the domain. For example, the security policy for data in a domain may include policies for authentication methods, access authorization check levels, key distribution methods, and encryption methods.

Authentication methods include user passwords, symmetric keys, public keys, one time passwords, graphical passwords, and biometrics, which are more secure.

The access authority check level includes session-specific verification, connection-specific verification, packet-specific verification, log or reviewing support, and the latter corresponds to a higher security level.

Key distribution methods include authentication server key forwarding, cross domain key exchange, real-time key forwarding, freshness per session, freshness per connection, freshness per packet, and more. do.

Encryption methods include symmetric key encryption such as DES (Data Encryption Standard), asymmetric key encryption such as RSA, support for watermarking, nonrepudiation support, and privacy protection. do.

The security scheme of each security policy as described above may be graded differently according to the security level.

1 is an exemplary diagram for explaining an example of data security level scoring used in a data access method on a cross domain according to an embodiment of the present invention.

Referring to FIG. 1, in the authentication method, a method such as 0.1 for a user password scheme, 0.2 for a symmetric key scheme, 0.4 for a public key scheme, 0.5 for a one-time cipher scheme, 0.7 for a graphical cipher technique, and 1.0 for a biometric scheme You can assign a score. In this case, you will receive a score corresponding to the highest security level you support. In other words, in the authentication method, if the user password method, symmetric key method, public key method, One Time password method, graphic password method, and biometrics method are all supported, 1.0 is given and only One Time password method is supported. In this case, 0.5 point is awarded.

Similarly to the foregoing, scores may be assigned to each security scheme belonging to an access right check level, a key distribution method, and an encryption method. Thus, if the security policy for data of a specific domain is composed of the four security policies, the data security level for data belonging to the domain is in the form of a vector consisting of four values. That is, the data security level vector D _S = (x, y, z, u) = (authentication method score, access authority check level score, key distribution method score, encryption method score).

The "domain trust rating" is a measure of the trust level of the domain itself. Each domain in the Web of Trust structure can obtain its own domain trust rating from a Certificate Authority (CA). The domain confidence level usually has a value in the range of 0.1 to 1.0, and in particular, may be set as 0.1, 0.5, 1.0. A domain trust level of 0 is set for untrusted domains, in which case the security level negotiation or data transmission to the domain is rejected.

Web of Trust is a technique for measuring the level of trust between users and issuing certificates. Each user can determine the trust level for another user's certificate or key, which can be derived to create another trust relationship. In Web of Trust, the overall trust level can be determined by considering the introducer trust level, certificate trust level, and key suitability trust level. The trust level of the certificate introduced by the introducer is usually set equal to the trust level of the introducer. For example, if domain B is signed by a certificate authority that is fully trusted by domain A, then domain A can fully trust domain B, so the certificate trust level or key suitability trust level for domain B is set to 1 point. Will decide. Details of the Web of Trust can be easily grasped from related publicly known technologies and technical literature, so the following description is omitted.

The "data access level" means a level of access or a level of authority required by the domain when accessing specific data in the domain, and may be calculated particularly from a combination of a data security level and a domain trust level. For example, the data access class can be defined as a scalar product of the data security class vector and the domain trust class number. That is, the data access class vector D _A = tD _S = (tx, ty, tz, tu) for the data security class vector D _S = (x, y, z, u) and the domain trust class t.

"User privilege level" means a level of authority for a user or a network node to access data in a specific domain. The user permission level corresponds to a data access level to allow a user to access data in a specific domain. Limit level. In other words, a user with a given user privilege level can access all data below the data access level equal to or lower than that user level in a particular domain, but access data with a data access level higher than that user level. Can not.

The user privilege level may take the form of a user privilege level vector or one numerical value corresponding to the data access level. The value of the user privilege level may be determined in detail by a specific combination of security policies such as an authentication method constituting the data access level, or when the data access level is evaluated as a whole, unclassified, confidential, and confidential ( Depending on the level of Secret or Top Secret, it may be decided from several predetermined values corresponding to it. For example, for users who can only access unsecured data, the user privilege level vector U _A = (a, b, c, d) = (0, 0, 0, 0), users with access to secret data In case of, the user authority class vector U _A = (a, b, c, d) = (0.2, 0.3, 0.4, 0.1) can be determined. The user privilege level can be freely determined by each domain without agreement with other domains.

Hereinafter, the data security level, the data access level, and the user permission level have a vector form, and the domain trust level has a scalar form.

2 is a flowchart illustrating a data access method on a cross domain according to an embodiment of the present invention.

Referring to FIG. 2, the data access method on the cross-domain according to an embodiment of the present invention is largely normalized with the data security level of the data of the domain (S110), and the data access level when accessing the data of the domain ( Determining whether to allow according to the normalized data security level) and the user right level (S120).

First, the step (S110) of normalizing the data security level of the data of the domain will be described.

In a cross-domain environment, the security policy of each domain may be different, and the security level required by "security level 1" in one domain may not match the security level required by "security level 1" in another domain. . For example, domain A divides the data security rating into 26 grades of A ~ Z, while domain B divides the data security grade into 14 grades of temporary ~ low grade. The provisional ratings of A and domain B are not exactly equivalent security levels. Therefore, a normalization process is needed to match domain A's data security level with domain B's data security level in order to ensure that a user in domain A has access to data in domain B or vice versa. Hereinafter, a case in which different domains A and B exist as an example of a cross domain environment will be described.

Clustering Algorithm may be used as a method of normalizing the data security level of data of a domain in a cross domain environment. The method of normalizing the data security level is not limited to a specific method, and may be any possible method capable of mapping the data security level defined by the domain A to the data security level defined by the domain B. Hereinafter, a clustering technique will be described as an example of a method of normalizing the data security level.

In using the clustering technique, domain A and domain B may perform a clustering process on data of each domain after agreeing the number k of clusters. The k-means technique is an example of this. The consensus process can be made through a certification authority (CA). The clustering technique is not limited to a specific technique, and may be any possible type of technique capable of mapping a group of data security classes defined by domain A to a group of data security classes defined by domain B. Hereinafter, the k-means technique will be described as an example of the clustering technique.

In k-means technique, k is selected by random selection technique, Furthest First technique (D. Hochbaum, D. Shmoys, A best possible heuristic for the k-center problem, Mathematics of Operations Research, 10 (2): 180 -184, 1985), etc., and k-means for several k-values can be used to select k with the best clustering results.

The k-means clustering technique is described below. The k-means clustering technique reconstructs n data into k clusters smaller than n. The detailed process is as follows.

(Step 1) Choose a total of k medians representing each cluster.

(Step 2) The median of the closest distances is found for n data and assigned to the cluster of the median.

(Step 3) Calculate a total of k medians from the data assigned to each cluster.

(Step 4) Steps 2 and 3 are repeated until the median meets a predetermined criterion.

The distance in step 2 may be the Euclidean divergence, and the predetermined criterion in step 4 may be the case where it no longer converges without a change in the median.

3 is a conceptual diagram illustrating a k-means technique in a data access method on a cross domain according to an embodiment of the present invention. Where k is assumed to be 3.

Referring to (a) of FIG. 3, a total of twelve data shown by white circles and three median values shown by gray circles are shown. The number i in the gray circle indicates that the median value shown by the gray circle is the median of cluster i. As such, the process of selecting three intermediate values representing three clusters corresponds to step 1.

Referring to FIG. 3B, a process of finding the median of the closest distances for each of the 12 data and assigning the median to the cluster represented by the median is shown. The number i in the white circle indicates that the data represented by the white circle is the data assigned to cluster i. As such, the process of allocating 12 data to three clusters corresponds to step 2.

Referring to FIG. 3C, a process of calculating k median values by calculating median values of data allocated to each cluster is shown. Gray circles with dotted outlines represent the current median, and gray circles with solid outlines represent the newly calculated median. In the case of cluster 1, since there was only one assigned data, the data value itself is the median of cluster 1. In FIG. 2C, although the data of cluster 1 is not separately illustrated, the same data as the median of cluster 1 exists. Similarly, in the case of cluster 2 and cluster 3, the median value is calculated from the data values belonging to each cluster. In this way, the process of calculating three median values from a total of twelve data assigned to three clusters corresponds to step 3.

Referring to FIG. 3 (d), the median value newly calculated through step 3 is shown. If it is determined that the clustering process is continued until the median no longer fluctuates, step 2 and step 3 are added since the median fluctuation has occurred as shown in (b) and (d) of FIG. 2. Will be repeated more. This process corresponds to step 4 above.

The data security level may have one numeric form or a vector form consisting of a plurality of numerical values. Therefore, the above-described clustering technique or k-means technique may be performed according to the distance criteria such as Euclidean distance regardless of the data security level.

After performing clustering on the data security level as described above, the normalized data security level, that is, the final data access level is calculated by combining the clustered data security level with the domain trust level. For example, the product of the clustered data security level and domain trust level may be defined as the data access level. When the clustered data security degree for each data is a vector form, it may be defined as a scalar product with a domain trust level.

4 is a conceptual diagram illustrating a data access level in a data access method on a cross domain according to an embodiment of the present invention.

Referring to FIG. 4, it can be seen that domain A and domain B have agreed the number of clusters to 2, and data access classes for data belonging to each domain are shown. Data a and b of domain A were assigned to cluster 1 and data c to cluster 2. All data in domain B were assigned to cluster 2, i, c, and so on. Data c and data have an equivalent data access class, but data a and data have no equivalent data access class. For example, a user with access to data a can access data A, B, D, and D, but a user with access to data A can only access data c. You cannot access a and b.

Referring back to Figure 2, after completing the step of normalizing the data security level of the data of the domain (S110), when accessing the data of the domain allowed according to the data access level (normalized data security level) and the user permission level In operation S120, a determination is made.

Unlike public domains where anyone can access data without any restrictions, there is an Attribute Certificate Issuer network node in the protected domain that controls data access according to certain security policies.

The issuer of an attribute certificate issues an attribute certificate containing information on data access authority to all users or network nodes in its domain. Alternatively, the property certificate issuer may issue a property certificate including information on data access authority to a user of another domain or a network node of the other domain when a user of another domain wants to access data of a domain to which the property certificate belongs. . In other words, the user or network node issues an attribute certificate directly from the issuer of the attribute certificate of the domain to which it is trying to access, or from the issuer of the attribute certificate of its own domain, which has established a trust relationship with the issuer of the attribute certificate of the domain to which it is accessing. I can receive it.

5 is a conceptual diagram illustrating an attribute certificate used in a data access method on a cross domain according to an embodiment of the present invention.

Referring to FIG. 5, an attribute certificate may include an attribute certificate version, a user identifier to access data, a domain to which data to be accessed belongs, or an attribute certificate issuer identifier, an encryption or integrity algorithm identifier of a domain to which a user belongs to data, It may include information about the certificate serial number, the attribute certificate validity period, and the user privilege level.

The user presents the issued attribute certificate to the domain to which the data he wishes to access belongs. In particular, the guard of the domain compares the user authority level described in the attribute certificate with the data access class of the data to be accessed. To determine access. In this case, the user can access data of a level equal to or lower than a user privilege level described in the issued attribute certificate.

The domain or domain's guard is the attribute specified in the data access class vector D _A = (tx, ty, tz, tu) of the data requested by the user and the attribute certificate presented by the user, that is, the user privilege class vector U _A = ( a, b, c, d) is checked to determine whether access is allowed. In this case, you define difference = min (a tx, b ty, c tz, d tu), and if difference <0, you can disallow access. That is, if any element of the user privilege class vector does not meet the security level of the corresponding element of the data access class, data access is denied. For example, if the data access class vector of data requested by the user is D _A = (0.5, 0.5, 0.5, 0.5), the user privilege class vector U _A = (0.4, 0.6, 0.7, 0.5), difference = -0.1, so that the user is not allowed to access the data.

6 is a flowchart illustrating a data access method on a cross domain using the k-means technique according to an embodiment of the present invention.

As described with reference to FIG. 2, the data access method on the cross-domain according to an embodiment of the present invention largely normalizes the data security level of the data of the domain (S110) and the user when accessing the data of the domain. And determining whether to allow according to the permission level (S120).

Referring to FIG. 6, the data security level normalization step (S110) of the data of the domains may include agreeing the number of clusters k between domains (S111), and performing k clustering on the basis of the data security level of data of each domain. And a step S115 of calculating a data access level from a combination of a data security level and a domain trust level for data of each domain.

In the case of accessing the data of the domain, determining whether to allow according to the user privilege level (S120) issuing an attribute certificate specifying the user privilege level (S121), an attribute issued from a user accessing the data of the domain. It may include the step of presenting the certificate (S123), determining whether the user permission level specified in the attribute certificate is equal to or higher than the data access level of the data (S125) and allowing access to the data of the domain (S127). .

The cluster number agreement step (S111), clustering step (S113), data access level calculation step (S115), property certificate issuance step (S121), property certificate presentation step (S123), user authority level and data access level check For step S125 and the step of allowing access to domain data (S127), the data security level normalization step (S110) of the data of the domain and the data of the domain in the data access method on the cross domain according to the embodiment of the present invention. In the case of accessing to the step S120 of determining whether to allow according to the user permission level can be understood as described with reference to Figs. 1 to 5, the description thereof will be omitted.

7 is a block diagram illustrating a configuration of a data access system on a cross domain according to an embodiment of the present invention.

Referring to FIG. 7, a data access system on a cross domain according to an embodiment of the present invention includes an attribute certificate issuer 210, a host 220, and a guard 230. The protected domain may be via an edge router 240 in connection with another public domain or another protected domain. Other protected domains, such as Protected domain B shown in FIG. 7, may likewise include attribute certificate issuer 310, host 320, and guard 330.

Specifically, the Attribute Certificate Issuer 210 normalizes the data security level of data of its own domain corresponding to the data security level of data of another domain, and the user or host 220 or 320 belonging to another domain or own domain. Issue a certificate to the network node.

The attribute certificate issuer 210 may use a clustering technique in normalizing the data security level. In this case, if the k-means technique is used as the clustering technique, the number k of clusters can be agreed through a certificate authority (CA, 250).

The attribute certificate issuer 210 may normalize the data security level in consideration of the domain trust level, where the domain trust level has a meaning of adding a kind of weight to the clustered data security level. In this case, for example, the attribute certificate issuer 210 may define a product of the data security level and the domain trust level as the data access level.

The attribute certificate issuer 210 may obtain its domain trust rating from a Certificate Authority (CA), which is the highest authority of the Web of Trust structure, in determining the domain trust rating.

The host 220 presents the property certificate issued from the property certificate issuer 310 of another domain or the property certificate issuer 210 of its own domain to the guard 330 of the other domain, and the user included in the property certificate. Depending on the privilege level, access is made to data in other domains, for example, data from hosts 320 in other domains.

The guard 230 may include attribute certificates presented by the host 320 of another domain and data of the own domain to which the host 320 of the other domain tries to access, for example, data of the host 220 of the own domain. The data access of the host 320 of the other domain may be controlled by comparing the normalized data security level of the other domains. Alternatively, the guard 230 transmits the attribute certificate presented by the host 320 of the other domain to the attribute certificate identifier 210 of the own domain, and the attribute certificate identifier 210 of the own domain is similar to the host of the other domain. Data access of 320 can be controlled.

Guard 230 controls security mechanisms for sharing and transferring information in cross domain systems having different security levels. Typically, the guard 230 supports functions related to data safety (Sanitation), data filtering (Review), the connection between the protected network and the public network, retransmission, access restriction and security. The details of the guard can be easily understood from related publicly known technologies and technical literature, so the following description is omitted (Jeremy Epstein, "Architecture and concepts of the ARGuE Guard", 15th Annual Computer Security Applications Conference, (ACSAC), December 1999).

In summary, the attribute certificate issuer 210 of domain A and the attribute certificate issuer 310 of domain B agree, via a certification authority (CA, 250), the number of clusters k that must be determined in advance in the clustering technique. Through the process, the data security level of domain A and domain B is normalized. It also trusts its own attribute certificates through a CA (250).

When host 320 in domain B attempts to access data in host 220 in domain A, host 320 in domain B is issued an attribute certificate. In this case, the host 320 of the domain B receives the attribute certificate from the attribute certificate issuer 210 of the domain A, or the attribute of the domain B which has formed a trust relationship through normalization with the attribute certificate issuer 210 of the domain A. The certificate issuer 310 may be issued.

Host 320 of domain B presents the issued attribute certificate to guard 230 of domain A, and domain A guard 230 attempts to access the user privilege level specified in the attribute certificate and domain 320's host 320 to access. It is determined whether to allow access by comparing the data access level of the data of the domain A or the attribute certificate issuer 210 of the domain A, which has received the attribute certificate from the guard 230 of the domain A, in a similar manner. You can decide. The guard 230 of the domain A may obtain information regarding the data access level through the attribute certificate issuer 220 of the domain A. If the guard 230 of the domain A or the attribute certificate issuer 210 grants access, the host 320 of the domain B can access the data of the host 220 of the domain A.

The attribute certificate issuer 210, the host 220, the guard 230, the data security level, the domain trust level, the user privilege level, and the attribute certificate cross each other according to an embodiment of the present invention. In the data access method on the domain, the step of normalizing the data security level of the data of the domain (S110) and the step of determining whether to allow according to the user permission level when accessing the data of the domain (S120) FIGS. 1 to FIG. Since it can be understood similarly as described with reference to 6, the description thereof is omitted.

Although described with reference to the above embodiments, those skilled in the art will understand that various modifications and changes can be made without departing from the spirit and scope of the invention as set forth in the claims below. Could be.

1 is an exemplary diagram for explaining an example of data security level scoring used in a data access method on a cross domain according to an embodiment of the present invention.

2 is a flowchart illustrating a data access method on a cross domain according to an embodiment of the present invention.

3 is a conceptual diagram illustrating a k-means technique in a data access method on a cross domain according to an embodiment of the present invention.

4 is a conceptual diagram illustrating a data access level in a data access method on a cross domain according to an embodiment of the present invention.

5 is a conceptual diagram illustrating an attribute certificate used in a data access method on a cross domain according to an embodiment of the present invention.

6 is a flowchart illustrating a data access method on a cross domain using the k-means technique according to an embodiment of the present invention.

7 is a block diagram illustrating a configuration of a data access system on a cross domain according to an embodiment of the present invention.

Explanation of symbols on the main parts of the drawings

210, 310: property certificate issuer 220, 320: host

230, 330: Guard 240: Edge Router

250: certification authority

Claims (19)

(a) normalizing the data security level of data in the domain; And (b) determining whether to allow the data according to the normalized data security level and user permission level when accessing the data of the domain; Step (a) is a data access method on a cross domain, characterized in that to normalize the data security level using a clustering technique. delete The method of claim 1, Step (a) is a method of accessing data on cross domains, after k (k is the number of clusters) is agreed between different domains, and the data security level is normalized using k-means clustering technique. The method of claim 1, The step (a) of the data access method on the cross domain, characterized in that to normalize the data security level in consideration of the domain trust level rather than the clustering technique. The method of claim 4, wherein And (a) normalizing the data security level based on the product of the data security level and the domain trust level rather than the clustering technique. The method of claim 4, wherein The domain trust level is determined by a Web of Trust technique. The method of claim 1, And the data security level includes information on at least one of an authentication method, an access authority check level, a key distribution method, and an encryption method required to access the data. The method of claim 1, In step (b), the attribute certificate is presented, and the access authorization of the data of the domain is determined according to the user authority level included in the attribute certificate and the normalized data security level of the data of the domain. Data access on cross domains. The method of claim 1, Step (b) controls access to data of the domain by using an attribute certificate including information on a user privilege level, The attribute certificate includes information about an attribute certificate issuer identifier, an attribute certificate validity period, and a user privilege level. In accordance with the data security level of data in other domains, clustering techniques are used to normalize the data security level of data in own domains, issue attribute certificates to users or network nodes in their domains, and properties presented by hosts in other domains. An attribute certificate issuer for controlling data access of a host in the other domain by comparing a certificate and a normalized data security level of data in its own domain to which the host in the other domain attempts to access; And A host for presenting an attribute certificate issued by an attribute certificate issuer of its own domain to another domain and including a host accessing data in another domain according to a user privilege level included in the attribute certificate. delete The method of claim 10, And the property certificate issuer agrees k with the property certificate issuer of another domain through a certification authority, and then normalizes the data security level using a k-means clustering technique. The method of claim 10, The attribute certificate issuer normalizes the data security level in consideration of a domain trust level rather than the clustering technique. The method of claim 13, And the attribute certificate issuer normalizes the data security level based on a product of the data security level and the domain trust level rather than the clustering technique. The method of claim 13, The attribute certificate issuer determines the domain trust level by using a Web of Trust technique. The method of claim 10, And the data security level includes information on at least one of an authentication method, an access authority checking level, a key distribution method, and an encryption method required to access data. The method of claim 10, The attribute certificate includes information about an attribute certificate issuer identifier, an attribute certificate validity period, and a user privilege level. In accordance with the data security level of data in other domains, clustering techniques are used to normalize the data security level of data in own domains, issue attribute certificates to users or network nodes in other domains, and properties presented by hosts in other domains. An attribute certificate issuer for controlling data access of a host in the other domain by comparing a certificate and a normalized data security level of data in its own domain to which the host in the other domain attempts to access; And A host for presenting an attribute certificate issued by an issuer of an attribute certificate in another domain to another domain, and including a host accessing data in another domain according to a user privilege level included in the attribute certificate. A program of instructions that can be executed by a digital processing device that performs a data access method on a cross domain is tangibly implemented, and a recording medium recording a program that can be read by the digital processing device, (a) normalizing the data security level of data in the domain; And (b) determining whether to allow the data according to the normalized data security level and user permission level when accessing the data of the domain; Step (a) is a recording medium recording a program, characterized in that to normalize the data security level using a clustering technique.

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