Encryption-Based Multilevel Model for DBMS - Multilevel Security for Relational Databases - page 91

Table 5.1 Multilevel Relational Database

EMPLOYEE C-EMPLOYEE DEPARTMENT C-DEPARTMENT SALARY C-SALARY TC

Ahmed U Accounting U 7,000 U U

Ahmed S Accounting S 7,000 S S

Mohamed TS Sales TS 10,000 TS TS

Table 5.2 Encryption-Based Multilevel Relational Database

EMPLOYEE DEPARTMENT SALARY TC

U

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S

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Table 5.3 Comparison between Encryption-Based Multilevel Database Model and Commercial
Database Systems such as DB2 (IBM) and ORACLE

ENCRYPTION-
BASED MULTILEVEL
DATABASE

DB2 ENCRYPTED
FIELDS

ORACLE TRANSPARENT
DATA ENCRYPTION MODEL/CRITERIA

Encryption in
multilevel security

Supported Not supported Not supported

Encryption type Row-based

encryption (one
password per row)

Column-based
encryption (one
password per column)

Column-based
encryption (one
password per column)

Encryption key Key is managed by

database engine

Key provided by the
user at runtime

Key provided by the user
at runtime

DB2 (IBM) and ORACLE that support encryption in their database
management systems.
The symmetric encryption keys are stored as a hidden property for
the security classification levels of the multilevel database security.
he database administrator cannot read the encryption keys. He can
only read the security classification levels of the multilevel database
security.
In the encryption-based multilevel database model, caching has
an impact that should be taken into consideration as a plain text.
The impact of the caching is due to storing the decrypted data during
the transaction execution in the memory, which is a problem.