Concepts of Database Security - Multilevel Security for Relational Databases - page 6

There are many algorithms for encryption, such as data encryption
standards (DES), triple DES, and advanced encryption standards
(AES).
• Integrity can be defined as a process for preventing unauthor-
ized alteration to the sensitive data stored in the relational
database. The integrity of data is not only whether the data
is correct, but also whether it can be trusted and relied upon.
Database integrity ensures the accuracy and the consistency
of the data entered into the relational database.
• Availability can be defined as a process for preventing loss of
access to relational database services. Databases must have no
unplanned downtime.
In relational databases, many layers of security can be used to
ensure database security [7]. The security layers can be classified into
the following:
• Authentication can be defined as the concept of verifying the
identity of a user that needs to access the relational database.
Each user should identify himself before having access to data
stored in the relational database system. Authentication may
happen at different levels; for example, authentication can
be performed by the relational database itself or allow other
external methods to authenticate users.
• Access controls (authorization) can be defined as setting rules
that define whether the user has access to the data in the rela-
tional database. Authorization rules manage the modification
of data in the relational database. Access controls are proce-
dures that are defined to manage authorizations of the data in
the relational database.
• Integrity can be defined as a group of rules that present the
correct state of the relational database during the database
modification.
• Auditing can be defined as keeping track of all security rel-
evant actions issued by a user.
In this topic, the main focus is directed toward aspects related to
access controls. An access control mechanism ensures data confiden-
tiality. Whenever a subject tries to access a data object, the access