RANDy - A True-Random Generator Based On Radioactive Decay

This paper presents a physical random number generator for mainly cryptographical applications based on alpha decay of Americium 241. A simple and low-cost implementation is shown to detect the decay events of a radioactive source often found in common household smoke detectors. Three different algorithms for the extraction of random bits from the exponentially distributed impulses are discussed. In the concrete application a speed optimized method was chosen to gain a reasonable high data rate from a moderate radiation source (0,1 μCi). To the author’s best knowledge this technique has not been applied so far in the context of radiation-based random generators. A tentative application of statistical suits of tests indicates a high quality of the data delivered by the device.