Public Class MyServiceAuthorizationManager
    Inherits ServiceAuthorizationManager

    Protected Overrides Function CheckAccessCore(ByVal operationContext As OperationContext) As Boolean

        ' Extract the action URI from the OperationContext. Match this against the claims
        ' in the AuthorizationContext.
        Dim action As String = operationContext.RequestContext.RequestMessage.Headers.Action
        Console.WriteLine("action: {0}", action)

        ' Iterate through the various claim sets in the AuthorizationContext.
        Dim cs As ClaimSet

        For Each cs In operationContext.ServiceSecurityContext.AuthorizationContext.ClaimSets
            ' Examine only those claim sets issued by System.
            If cs.Issuer Is ClaimSet.System Then
                ' Iterate through claims of type "http://example.org/claims/allowedoperation".
                Dim c As Claim
                For Each c In cs.FindClaims("http://example.org/claims/allowedoperation", Rights.PossessProperty)
                    ' Write the claim resource to the console.
                    Console.WriteLine("resource: {0}", c.Resource.ToString())

                    ' If the claim resource matches the action URI then return true to allow access
                    If action = c.Resource.ToString() Then
                        Return True
                    End If
                Next c
            End If
        Next cs
        ' 
        ' If this point is reached, return false to deny access.
        Return False

    End Function