- 學位論文
情境角色與隔離式權限控管整合模型於工作流程之應用
An Integrated model of CR-RBAC and I-RBAC and Its Application to Workflow System
摘要
情境角色是透過角色的概念表達系統中的環境限制。在一個情境權限控管系統中，如果使用者不能滿足情境限制，則無法啟用情境角色取得情境權限來完成工作。要完成一個工作流程，必須依序的完成流程中定義的所有工作，如果因某一項工作具有情境限制而指派的使用者無法滿足情境限制，不能啟用情境角色來完成工作，這樣會使後續的工作都無法完成，導致流程延宕。 本論文將整合情境角色與隔離角色的權限控管模型運用在工作流程中。若執行某一項工作的使用者無法滿足情境限制啟用情境角色，則可以利用隔離角色在隔離環境中暫時的完成這項工作，使流程可繼續進行並減少流程等待的時間。然而暫時完成的工作仍然需要使用情境角色在主機環境中執行。若無法在主機環境執行，則此工作不是真正完成，必須將其後續的工作回復 ( Rollback )。 我們以一個銀行信用貸款流程為例來說明並實作此模型。我們設定貸款“核准”這項工作必須在公司內執行，如果執行核准這項工作的使用者無法啟用情境角色，則可以啟用隔離角色在隔離環境中暫時完成這項工作並保留貸款，再經由“覆核”這項工作在主機環境執行。透過隔離角色暫時執行“核准”時系統會先保留此流程申請的貸款金額。實作中使用Activiti流程引擎驅動流程進行，任務可以設定對應的程式邏輯。若是“覆核”結果是Deny，系統會將保留的金額釋出並且通知其他需要此筆金額的流程繼續進行。
並列摘要
Context roles can be used to describe context constraints in an RBAC system. In a CR-RBAC system, a user cannot activate a context role to get the permissions to complete a job if the user does not satisfy the context constraints. To complete a workflow, one must execute successfully all the tasks that are defined sequentially. When the context constraints associated with some tasks of a workflow are not satisfied, those tasks cannot be executed and thus the workflow cannot proceed. This will cause delay of the workflow. In this thesis, we will introduce a model that integrated CR-RBAC and I-RBAC, and show its application to a workflow. If a user who was assigned to a task of a workflow does not satisfy the associated context constraint, the user cannot activate a context role to execute the task. But the user can use an isolation role to execute the task in an isolation environment temporarily. The workflow can still proceed without waiting. But the task must still be completed on host environment using the context role when the context constraints are satisfied. If the task cannot be completed on host environment, the task and its subsequent tasks must be rollbacked. A bank loan workflow was used as an example to illustrate our model. We assume that the task "Approve" has to be executed inside the bank. The user who was assigned to do the task "Approve" can use an isolation role to complete this task in isolated environment if he cannot meet the context constraints to activate a context role. Afterward the task can be confirmed in host environment by the task "Confirm". We used Activiti workflow engine in our implementation, where a program can be attached to a task. The system will reserve the loan amount of the workflow when the task "Approve" is executed by an isolation role. This amount will be restored if the final result of "Approve" is deny, and the system will notify other waiting workflows which need this amount to continue.