Encryption-Based Multilevel Model for DBMS - Multilevel Security for Relational Databases - page 110

The Jajodia-Sandhu model has bad performance because of the impact
of union operation between single-level relations in the recovery algo-
rithm. The SeaView model has very bad performance because of the
impact of the JOIN operation between vertical single-level relations
and union operation between horizontal single-level relations in the
recovery algorithm.
From the experimental results in the previous section, the
encryption-based multilevel database model, which is a combination
of the MLR model and encryption algorithm, has performance better
than the performance of the MLR model in retrieving data from the
multilevel database. This improvement in performance is due to the
reduction of the multilevel database size, removing the attributes clas-
sification columns, and encrypting the records by an encryption key
according to its security level. Also, by adding an encryption algorithm,
the overhead in the MLR model of checking the security class level
hierarchy for each data element when retrieving data is reduced. Instead
of checking the security class level hierarchy when getting data in the
encryption-based multilevel database model, the encryption keys belong
to the subject to encrypt each data element that is used when retriev-
ing data. The performance of the encryption-based multilevel database
model is less than the performance of the MLR model in updating
data because the overhead of supporting the encryption algorithm in
the update query is executed. Table 5.4 shows the reduction in database
size in the encryption-based multilevel database model compared to the
original MLR model and the other MLS models.

Table 5.4 Reduction in Database Size in Proposed Model Compared to Original MLR Model and
Other MLS Models

ENCRYPTION-
BASED
MULTILEVEL
DATABASE

BELIEF-
CONSISTENT
MLS

MODEL/
CRITERIA

ORIGINAL
MLR

JAJODIA-
SANDHU

SMITH-
WINSLETT

SEAVIEW

Actual
database size
in megabytes

106 129 116 98 110 91

Reduction in
database size
in our proposed
model

Reduced
by 15%

Reduced
by 30%

Reduced
by 22%

Reduced
by 8%

Reduced by
18%