Patent ID: 8074081

Claim:
A data storage device, comprising: a plurality of data storage units; a physical random number generator with a noise source based on a physical noise process, implemented to generate physical random numbers; a pseudo random number generator implemented to generate pseudo random numbers; a combiner implemented to combine the physical random numbers and the pseudo random numbers; and a replacer implemented to select one of the data storage units, in which data is to be stored, depending on a sequence of driving signals, wherein the combiner is implemented to feed, when there is a new physical random number, the new physical random number into the pseudo random number generator as a seed for re-initializing, and wherein the combiner is implemented to generate the sequence of driving signals using one of the pseudo random numbers, which has been generated by the pseudo random number generator based on the new physical random number as a seed; and a mode controller implemented to access the combiner or the replacer via a mode line so as to switch, within a predetermined time interval, from a random non-deterministic replacement strategy used in selecting a data storage unit, which is based on the physical random numbers from the physical random number generator to a deterministic replacement strategy used in selecting a data storage unit, which is either solely based on the pseudo random numbers or is an alternative deterministic replacement strategy, wherein the mode controller is implemented to bring about the deterministic replacement strategy when calculations in program sections which are less relevant in terms of security are to be performed in a processor coupled to the data storage device or when guaranteed or predictable run times are required for calculations in program sections by the processor, and to bring about the random non-deterministic replacement strategy when calculations in program sections which are more relevant in terms of security are to be performed in the processor coupled to the data storage device.