Cache unit useful for secure execution

A cache unit that is configured to retain: a plurality of cache blocks; a plurality of owner indicators, and a plurality of validity marks. For each cache block of the plurality of cache blocks exists a corresponding owner indicator in the plurality of owner indicators. An owner indicator corresponding to a cache block is capable of identifying an entity that caused the cache block to be fetched to the cache unit. For each cache block of the plurality of cache blocks exists a corresponding validity mark in the plurality of validity marks. A validity mark corresponding to the cache block indicates whether a validation process performed on the cache block upon fetching thereof was successful. The cache unit may be useful for secure execution.