**Quantum Random Number Generator (QRNG)**

## What is QRNG?

A quantum random number generator is a device that utilizes the quantum phenomena to generate true random numbers. The measurement outcome of the microscopic particles is inherently random, one such example is beam splitter scheme where we can consider a photon sent to a beam splitter. The probability of the photon to travel in transmitted path and reected path is same i.e. the photon remains in superposition of both the paths till it is detected in either one of the two detectors which are placed in the transmitted and reected path respectively and thus the outcome is purely random.

## Why do we need QRNG ?

A random number is a number generated which is unpredictable, not reproducible and unbiased. A random number can be produced by either a software (deterministic algorithm) or hardware (physical process). A software generated random numbers are pseudo random numbers because they can be reproduced after a period of time. The physical random number generator (RNG) can be a classical process which is deterministic or a quantum process which is intrinsically random. The famous classical RNG which is coin tossing can be predicted if initial conditions are known. Thus pseudo random numbers are reproducible and classical RNG are essentially complex but yet deterministic. Genuine randomness is possible only by a Quantum random number generator which is based on the quantumness of microscopic system. At present commercial QRNG are there in market for example qStream of Quintessencelabs which can produce 1Gbit/s and QUANTIS manufactured by IDQuantique can produce 16Mbits/s.

## Where is QRNG required?

A quantum random number is an important resource and has many demanding applications viz gaming industry, cryptography, statistical research, simulation, deterministic RNG seeding.