Formal Analysis for Encryption- Based Multilevel Model for DBMS - Multilevel Security for Relational Databases - page 131

SH ( L ) = φ; while T = TV ( L ) ∪ TH ( L ) and TV ( L ) ∩ TH ( L ) = φ,
deleting any input from user S 1 ∈ SH ( L ) cannot affect the output to
S 2 ∈ SH ( L ).
6.8 Summary
This chapter presented the concept of the encryption-based multilevel
database model, which improved the performance of the multilevel
relational database by decreasing the database size and enhancing
the response time for retrieving the data from the multilevel rela-
tional database. The mathematical forms for the data manipulation
operations such as SELECT, INSERT, UPDATE, and DELETE of
the multilevel relational database were refined to match the effect of
adding the encryption algorithm to the multilevel relational database
model. The mathematical proof of the soundness, the completeness,
and the security was introduced to demonstrate that the encryption-
based multilevel database model is robust against database attacks
and free from covert channel problems. The mathematical model for
multilevel integrity properties such as entity integrity, polyinstantia-
tion integrity, data borrow integrity, foreign key integrity, and refer-
ential integrity was introduced to characterize the verification of the
encryption-based multilevel database model.