9 Access Control Systems for Geospatial Data and Applications
191
9.2 Background Knowledge on Data Security
9.2.1 Data Security
Broadly speaking, data security aims at protecting information against security
breaches. Security breaches can be categorized as unauthorized data observation,
incorrect data modification, and data unavailability.
Data unavailability occurs when information which is crucial for the functioning
of the organization is not ready when needed. Information security means assuring [8]:
• confidentiality, thus protecting data against unauthorized disclosures;
• integrity, thus preventing unauthorized data modification;
• availability, thus recovering from hardware and software errors and malicious
data denials.
These requirements raise practically in all application contexts. For example,
Chap. 10 in this book focuses on confidentiality and integrity requirements in the
context of outsourced-based architectures. In location-based applications, which is
our concern, confidentiality is requested to protect various types of information
which include, besides the information resources requested by the user, the location
of mobile users. Integrity is needed to protect, among others, the information which
is transmitted to and from the mobile devices against unauthorized modifications.
Data availability is also needed to ensure the availability of the position.
Data security is supported by various tools and systems, including authentication,
access control, and audit. Among these, access control is fundamental to ensure confidentiality and integrity of information resources made available to multiple users.
The component in charge of access control is the ACS. When a user tries to access
an information resource, a component of such system, the access control mechanism
checks the rights of the requester against a set of authorizations, usually specified
by a security administrator. An authorization states which user, or more generally,
which subject can perform which operation on which objects. An authorization is
defined as the triple: < s, op, ob j >, where s, op, and ob j refer to subject, operation,
and object, respectively. The subject identifies the holder of the authorization. It can
be a single or group of individuals or programs. The object identifies the resource.
The nature and granularity of the resource depend on the application. The operation defines what the subject is authorized to do with the specified object. The set of
authorizations defined by the organization constitutes the access control policy. Such
a policy is defined using a policy language based on an access control model. In what
follows, we present a classification of access control models.
9.2.2 Access Control Models
Access control models can be categorized into: mandatory, discretionary, and rolebased access control (RBAC) models. Mandatory access control (MAC) developed
in a military and national security setting; discretionary access control (DAC) has
191
9.2 Background Knowledge on Data Security
9.2.1 Data Security
Broadly speaking, data security aims at protecting information against security
breaches. Security breaches can be categorized as unauthorized data observation,
incorrect data modification, and data unavailability.
Data unavailability occurs when information which is crucial for the functioning
of the organization is not ready when needed. Information security means assuring [8]:
• confidentiality, thus protecting data against unauthorized disclosures;
• integrity, thus preventing unauthorized data modification;
• availability, thus recovering from hardware and software errors and malicious
data denials.
These requirements raise practically in all application contexts. For example,
Chap. 10 in this book focuses on confidentiality and integrity requirements in the
context of outsourced-based architectures. In location-based applications, which is
our concern, confidentiality is requested to protect various types of information
which include, besides the information resources requested by the user, the location
of mobile users. Integrity is needed to protect, among others, the information which
is transmitted to and from the mobile devices against unauthorized modifications.
Data availability is also needed to ensure the availability of the position.
Data security is supported by various tools and systems, including authentication,
access control, and audit. Among these, access control is fundamental to ensure confidentiality and integrity of information resources made available to multiple users.
The component in charge of access control is the ACS. When a user tries to access
an information resource, a component of such system, the access control mechanism
checks the rights of the requester against a set of authorizations, usually specified
by a security administrator. An authorization states which user, or more generally,
which subject can perform which operation on which objects. An authorization is
defined as the triple: < s, op, ob j >, where s, op, and ob j refer to subject, operation,
and object, respectively. The subject identifies the holder of the authorization. It can
be a single or group of individuals or programs. The object identifies the resource.
The nature and granularity of the resource depend on the application. The operation defines what the subject is authorized to do with the specified object. The set of
authorizations defined by the organization constitutes the access control policy. Such
a policy is defined using a policy language based on an access control model. In what
follows, we present a classification of access control models.
9.2.2 Access Control Models
Access control models can be categorized into: mandatory, discretionary, and rolebased access control (RBAC) models. Mandatory access control (MAC) developed
in a military and national security setting; discretionary access control (DAC) has