Consideration is given to the application of multiversionschedulers in multilevel secure database management systems (MLS/DBMSs).Transactions are vital for MLS/DBMSs because they provide transparencyto concurrency and failure. Concurrent execution of transactions maylead to contention among subjects for access to data, which in MLS/DBMSsmay lead to security problems. Multiversion schedulers reduce thecontention for access to data by maintaining multiple versions. Adescription is given of the relation between schedules produced inMLS/DBMSs and those which are multiversion serializable. The authorsalso propose a secure multiversion scheduler. They show that thescheduling protocol gives correct schedules and is free of covertchannels due to contention for access to data, i.e. the scheduler isdata-conflict-secure
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