Generation of Truly Random Numbers Using Si-NC LEDs

Generation of random numbers is absolutely vital in many applications particularly
cryptography. Random numbers can be obtained using pseudo random number generators
via deterministic algorithms whose unpredictability is not totally assured since
when the initial value is revealed, all the bits in the sequence will be readily
constructed. On the contrary, truly random numbers essentially need to be generated
through physical non-deterministic processes.
Considering the non-deterministic process of spontaneous emission of photons in
silicon nanocrystal (Si-NC) LEDs, they can be employed to generate quantum random
numbers. In our experimental setup the light emitted from the LED was detected by a
single photon avalanche photodiode (SPAD) through a bundle of optical fibers and
then by using a multichannel scaler (MCS) connected to a PC, sequences of bits were
extracted. To evaluate the randomness of the bit sequences the NIST test suit was
used. The generated bit sequences passed all the NIST tests by enforcing a dead time
of length equal to the bin-width and half the bin-width.
The quantum random number generator (QRNG) we produced enjoys the two main
advantages of very negligible bias and simple setup with a bit-rate of 0.6Mbps which
can be easily increased by adopting a parallel architecture and exploiting the CMOS
compatibility of all components.