A novel true random number generator based on QCA nanocomputing

True random number generators (TRNGs) are considered as an innovative basis to obtain unpredictable and irreproducible digital bit-streams in secure systems and communications. Because of its ultra-low power and extremely-small size features, the quantum-dot cellular automata (QCA) is most promising nanoelectronic technology for implementing digital systems with security capabilities. This paper presents a novel QCA implementation of TRNG, which is comprised of proposed cross-coupled circuit and cross-oriented structure, in order to generate truly random numbers. This implementation extracts the randomness from the oscillatory trajectory of QCA cross-coupled loop that is composed of XNOR gates only to guarantee the quality of randomness. Furthermore, it exploits the oscillatory metastability resulting from zero-energy QCA cells of cross-oriented structure that is connected across cross-coupled outputs to increase the quality of randomness. Its behavior is verified through QCA simulations and its architecture is passed statistical tests of random numbers. Consequently, the proposed QCA-based TRNG can be considered as a promising candidate for future security applications in Nano communications.