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channels and the starvation of the high transaction problems should
be prevented. In this section, the criteria for the correctness of the
enhanced secure multiversion concurrency control model will be
described as follows:
• Preventing the creation of the covert channel problem: The
low classification level transactions should not be delayed
when the high classification level transaction is in the execu-
tion phase.
• Preventing the starvation of the high transaction problem: If
the low classification level transactions need to be executed
when the high classification level transactions are executing,
the high transactions must not suffer from the repeated aborts
problem.
• Producing the serializable schedule for multilevel transac-
tions: Because of maintaining the consistency of the multi-
level relational database, the serializable schedule should be
presented for multilevel transactions.
• Preventing the retrieval anomaly problem when multiver-
sion data are run: The high security class level transactions
should read the right versions of the data, although there is a
creation of a new data version by the low security class level
transactions.
• The fast selection of the data version through more than one
version when multiversion data are run: While there are many
data versions in the multilevel relational database, the data
version selection needs to be fast.
7.5.1 Proof of Correctness
The enhanced secure multiversion concurrency control model should
not violate security requirement issues. This section will verify the
correctness of this model according to the criteria presented in the
previous section.
The covert channel is blocked by requiring the low security class
level transaction to be run when it is entered into the scheduler, and
by preventing the high security class level transactions when the low
transaction is executing [97].
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