Access Road Documentation

Access control analysis

Documentation

Examples of access control design with diagrams | Functional Quality Matrix | Non-Functional Quality Matrix | General Use Case | Access Road Architecture

Generic access control system model

In information systems, the accesses are based on two concepts :

• access done in and between the information systems,
• access rights that are managed by all the varied access control systems (ACS) that participate to the access control in an information system.

For exemple, lets consider a distributed environment where a web server with Linux and Apache, connects http users to a database on a Windows NT server through an object request broker. The access control systems (ACS) may be :

• on the Web server : Apache and Linux,
• on the local network and middleware: the firewall and the object request broker,
• on the database server : Windows NT and the database system.

In Access Road, one single information system may be modeled, or multiple interconnected information systems. Each information system has one or several access control systems. Access controls are designed and synthetized in this context.

The first generic conceptual model is a simplified diagram class in UML. It describes access in information systems. It's generic in the mean that it is independant of a specific ACS. It's conceptual because it doesn't describe the effective classes in the implementation or even the interfaces in the design. It must be viewed as a specification element.

There is three levels in the model :

• the reality level, that covers both the human, organisational, material ou technical domains of the reality. In this reality, there are RealEntities concerned by accesses.
• the information system level, where a RealEntity is identified in the concept of EntityIS (for exemple, a human - RealEntity - is identified by a personal name or a number),
• the access control level, where an EntityIS corresponds to an EntityACS (for exemple, the ACS may be an add-on system that forbids connexions between 10 pm and 6 am ; only a general EntityACS is then used with the simple criteria of the time).

Four concepts are in the front line in access :

• Resource, which is the entity accessed in the information system and controlled by the ACS. For exemple, these are computers, files, applications, relationals tables.
• Actor, which is entity who access to the resources, like an human user, a distant system, an application. Note : application is an exemple of entity that is both resource and actor.
• Access Rights for a couple (actor, resource), including the exclusions, that are managed by the access control system,
• Access Done for a couple (actor, resource), that is done by the information system under the control of access control systems.

The second generic conceptual model is a diagram class in UML. It is devoted to access control systems (ACS).

• This model is used in the design of a generic ACS. So, the generic conceptual model helps to provide a consistent and unified view of the main concepts implied in access control systems.
• A generic model allows a layered design : a hierarchy of abstractions corresponds to a hierarchy of implementations. Generic model leads to a framework where generic design and generic classes can be reused in the design and the implementation of every actual and future ACS manager in Access Road.
• Generic model is also usefull both for the IHM design of Access Road. It can provide to the Access Road user, a framework for the analysis of complex situations.

Three concepts are in the front line :

• Resource, which is the ACS view of the entity accessed in the information system and controlled by the ACS. For exemple, these are computers, files, applications, relationals tables.
• Actor, which is the ACS view of the entity who access to the resources, like an human user, a distant system, a software.
• Eligible Party, which is the median concept that allows an actor to be eligible for an access to a resource. For exemple, an account in an operating system is an eligible party, because it allows a human user logged into this account, to be eligible to an access.

There is also access right, which authorize or forbid access. Access rights are tightly connected to resources and eligible parties. In every ACS, actor's rights depend on the multiple eligible parties which may be connected to the actor. For exemple, in an operating system, an user is logging into an account which belongs to one group. His access rights on a resource depend on the access rights of the account and the access rights of the group.

Numerous ACS may participate to the final access rights of an EntityIS to a resource. The final rights depend on the specific access rights in every ACS, following simple or very complex rules. Moreover, an EntityIS may be identified with different names in several ACS. Lets consider an executable as an resource. In an operating system, it may be simply identified as a repository (or a folder) with specific rights, but in a transaction processing monitor, it may be identified as a transaction with another specific rights, or as a component of a transaction.

Let's see the generic access control system model in UML, that details the concepts connected to resources, actors and eligible parties.

These generic models define so, in the more general case, four layers of access rights that are applied to every entity :

• ACS-EP access rights for an eligible party or resource, considering couples (eligible party, resource) in a specific ACS - this layer is the only one coded in the Access Road database,
• ACS-A access rights for an EntityACS as actor or resource, considering couples (actor, resource) in a specific ACS - this layer is derived from the precedent,
• IS access rights for an EntityIS as actor or resource, considering couples (actor, resource), which are the effective access rights in the information system, with all the implied ACS - this layer is derived from the precedent,
• Effective access rights for a RealEntity, covering all the implied information systems in the real world - this layer is derived from the precedent.

Documentation

Examples of access control design with diagrams | Functional Quality Matrix | Non-Functional Quality Matrix | General Use Case | Access Road Architecture