A True Random Number Generator with Built-in Attack Detection

True random number generators (TRNGs) are extensively used in cryptography, simulations and statistics. Metastability is a way to generate true random numbers. By using electromagnetic radiation, a flip-flop in a metastable state can be manipulated to a known state. In this work, we introduce and analyze the concept of a randomized bit-cell, being able to simultaneously produce random numbers and detect active nonintrusive attacks. The experimental comparison with a standard TRNG yields an 11.5 times better distribution of zeros and ones while the TRNGs are under attack. The concept is extended by using a corrector. A perfect distribution can be gained at the expense of a delay which is proportional to the quality of the random source.