  Random number generation is crucial in many aspects of everyday life, as
online security and privacy depend ultimately on the quality of random numbers.
Many current implementations are based on pseudo-random number generators, but
information security requires true random numbers for sensitive applications
like key generation in banking, defence or even social media. True random
number generators are systems whose outputs cannot be determined, even if their
internal structure and response history are known. Sources of quantum noise are
thus ideal for this application due to their intrinsic uncertainty. In this
work, we propose using resonant tunnelling diodes as practical true random
number generators based on a quantum mechanical effect. The output of the
proposed devices can be directly used as a random stream of bits or can be
further distilled using randomness extraction algorithms, depending on the
application.
