A method for prioritized erasure of a non-volatile storage device, the method including the steps of: providing at least one flash unit of the storage device, wherein each flash unit has a plurality of blocks; writing data into the plurality of blocks; assigning an erasure-priority to each block, wherein the erasure-priority correlates with an erasure-priority of the data; and erasing the data in each block according to the erasure-priority of each block upon receiving an emergency-erase command. Preferably, the step of writing data into the plurality of blocks is performed in an arbitrary order in a first flash unit, and the step of writing into subsequent flash units is performed in correlation with the order in the first flash unit. Preferably, the step of erasing includes aborting erasure, before completing the erasure, for at least some of the plurality of blocks.