The information model for AuthorizationServices which allow Clients to request Access Tokens from a Server is shown in Figure 33.

image036.png

Figure 33 – The Model for Requesting Access Tokens from AuthorizationServices

This ObjectType represents a folder that contains AuthorizationService Objects which may be accessed via the Server. It is defined in Table 144.

Table 144 – AuthorizationServicesFolderType Definition

Attribute

Value

BrowseName

2:AuthorizationServicesFolderType

IsAbstract

False

References

NodeClass

BrowseName

TypeDefinition

Modelling Rule

Subtype of the FolderType defined in OPC 10000-5.

0:Organizes

Object

2:<ServiceName>

2:AuthorizationServiceType

OptionalPlaceholder

Conformance Units

GDS Authorization Service Server

This Object is an instance of AuthorizationServicesFolderType. It contains the AuthorizationService Objects which may be accessed via the GDS. It is the target of an Organizes reference from the Objects Folder defined in OPC 10000-5. It is defined in Table 145.

Table 145 – AuthorizationServices Object Definition

Attribute

Value

BrowseName

2:AuthorizationServices

TypeDefinition

2:AuthorizationServicesFolderType defined in 9.6.2.

References

NodeClass

BrowseName

TypeDefinition

Modelling Rule

Conformance Units

GDS Authorization Service Server

This ObjectType is the TypeDefinition for an Object that allows access to an AuthorizationService. It is defined in Table 146.

Table 146 – AuthorizationServiceType Definition

Attribute

Value

BrowseName

2:AuthorizationServiceType

IsAbstract

False

References

NodeClass

BrowseName

DataType

TypeDefinition

Modelling Rule

Subtype of the BaseObjectType defined in OPC 10000-5.

0:HasProperty

Variable

2:ServiceUri

0:String

0:PropertyType

Mandatory

0:HasProperty

Variable

2:ServiceCertificate

0:ByteString

0:PropertyType

Mandatory

0:HasProperty

Variable

2:UserTokenPolicies

0:UserTokenPolicy []

0:PropertyType

Optional

0:HasComponent

Method

2:GetServiceDescription

Defined in 9.6.6.

Mandatory

0:HasComponent

Method

2:RequestAccessToken

Defined in 9.6.5.

Optional

Conformance Units

GDS Authorization Service Server

The ServiceUri is a globally unique identifier that allows a Client to correlate an instance of AuthorizationServiceType with instances of AuthorizationServiceConfigurationType (see 9.7.4).

The ServiceCertificate is the Certificate required to check any Signature that is included with the Access Tokens. The ServiceCertificate may be a complete chain (see OPC 10000-6 for information on encoding chains).

The UserTokenPolicies Property specifies the UserIdentityTokens which are accepted by the RequestAccessToken Method.

The GetServiceDescription Method is used to read the metadata needed to request Access Tokens.

The RequestAccessToken Method is used to request an Access Token from the AuthorizationService.

RequestAccessToken is used to request an Access Token from an AuthorizationService. The scenarios where this Method is used are described fully in 9.3, 9.4 and 9.5.

The PolicyId and UserTokenType of the identityToken shall match one of the elements of the UserTokenPolicies Property. If the identityToken is not provided the Server should use the ApplicationInstanceCertificate and/or the UserIdentityToken provided for the Session (or the request if using a Session-less Method Call) to determine privileges.

If the associated UserTokenPolicy provides a SecurityPolicyUri, then the identityToken is encrypted and digitally signed using the format defined for UserIdentityToken secrets in OPC 10000-4.

This Method shall be called from an encrypted SecureChannel and from a Client that has access to the AccessTokenRequestor Privilege (see 9.2).

Signature

RequestAccessToken (

[in] UserIdentityToken identityToken

[in] String resourceId

[out] String accessToken

);

Argument

Description

identityToken

The identity used to authorize the Access Token request.

resourceId

The identifier for the Resource that the Access Token is used to access.

This is usually the ApplicationUri for a Server.

accessToken

The Access Token granted to the application.

Method Result Codes (defined in Call Service)

Result Code

Description

Bad_IdentityTokenInvalid

The identityToken does not match one of the allowed UserTokenPolicies.

Bad_IdentityTokenRejected

The identityToken was rejected.

Bad_NotFound

The resourceId is not known to the Server.

Bad_UserAccessDenied

The current user does not have the rights required.

Bad_SecurityModeInsufficient

The SecureChannel is not encrypted.

Table 147 specifies the AddressSpace representation for the RequestAccessToken Method.

Table 147 – RequestAccessToken Method AddressSpace Definition

Attribute

Value

BrowseName

2:RequestAccessToken

References

NodeClass

BrowseName

DataType

TypeDefinition

ModellingRule

0:HasProperty

Variable

0:InputArguments

0:Argument[]

0:PropertyType

Mandatory

0:HasProperty

Variable

0:OutputArguments

0:Argument[]

0:PropertyType

Mandatory

GetServiceDescription is used to read the metadata needed to request Access Tokens from the AuthorizationService.

Signature

GetServiceDescription (

[out] String serviceUri

[out] ByteString serviceCertificate

[out] UserTokenPolicy[] userTokenPolicies

);

Argument

Description

serviceUri

A globally unique identifier for the AuthorizationService.

serviceCertificate

The complete chain of Certificates needed to validate the Access Tokens provided by the AuthorizationService.

userTokenPolicies

The UserIdentityTokens accepted by the AuthorizationService.

Method Result Codes (defined in Call Service)

Result Code

Description

Bad_UserAccessDenied

The current user does not have the rights required.

Table 148 specifies the AddressSpace representation for the GetServiceDescription Method.

Table 148 – GetServiceDescription Method AddressSpace Definition

Attribute

Value

BrowseName

2:GetServiceDescription

References

NodeClass

BrowseName

DataType

TypeDefinition

ModellingRule

0:HasProperty

Variable

0:OutputArguments

0:Argument[]

0:PropertyType

Mandatory

This event is raised when a AccessToken is issued.

This is the result of a RequestAccessToken Method completing.

This Event and it subtypes are security related and Servers shall only report them to users authorized to view security related audit events.

Its representation in the AddressSpace is formally defined in Table 149.

Table 149 – AccessTokenIssuedAuditEventType Definition

Attribute

Value

BrowseName

2:AccessTokenIssuedAuditEventType

IsAbstract

True

References

NodeClass

BrowseName

DataType

TypeDefinition

Modelling Rule

Subtype of the 0:AuditUpdateMethodEventType defined in OPC 10000-5.

Conformance Units

GDS Authorization Service Server

This EventType inherits all Properties of the AuditUpdateMethodEventType. Their semantic is defined in OPC 10000-5.