The Instance-Based Multilevel Security Model - Multilevel Security for Relational Databases - page 150

Table 8.5 The Sensitive Key Value Problem

EMPLOYEE DEPARTMENT SALARY TC

Ahmed U Accounting U 7,000 U U

Ahmed S Sales S 8,000 U S

Ali TS Sales S 10,000 TS TS

8.2 The Instance-Based Multilevel Security Model (IBMSM)

The instance-based model presents a two-layered model to the data;
every layer represents a different domain (Figure 8.1) [102]. Every
layer saves data and performs operations as follows:

• The instance layer contains the instances with its properties of
the model in a specific domain. The instance layer can create
and manipulate data for the domain of instances.
• The class layer contains the classes that define the simi-
larities of the instances that belong to the instance layer.
The class layer can create and manipulate the classes in the
class layer.

The users can define an object with its properties by the classifica-
tion levels in the multilevel relational database. The IBMSM contains
the following parts: the instance, the class, and the control models
and will be described as follows:

User 3 User2 (TS)

User(S)

Class 2

Class 3

Class

Data

Figure 8.1 Two layers in IBMSM.