A true random number generator based on double threshold-switching memristors for image encryption

True random number generator (TRNG) that cannot be arbitrary attacked with predictable software algorithm is a promising data security solution. Memristors, possessing specific intrinsic stochasticity, are just appropriate to be the random sources for encryption applications. In this work, a TRNG system based on the stochastic duration time of double threshold-switching (TS) memristors is proposed. The reliable stochasticity of this system is mainly attributed to the gradual dissolution of Ag conductive channels and the synergistic effect of these two TS memristors. A digital circuit system based on the micro-controller unit is designed to produce stable random “0” and “1” bitstreams. The random data key generated by this double TS memristor TRNG passed the National Institute of Standards and Technology randomness tests without post-processing procedure. Taking advantage of the true random data key, the binary image can be encrypted and decrypted by executing the XNOR logic operation. In addition, the Gaussian noise effect on the decryption stability of image information secure communication is also analyzed. Although 90% Gaussian noise was applied to the original image, the pristine binary image still can be roughly recognized. This work demonstrates that the double TS memristors-based TRNG system has great potential for hardware security applications.