Method and apparatus for generating true random numbers by way of a quantum optics process

Abstract

A method and apparatus for generating true random numbers by way of a quantum optics process uses a light source to produce a beam which illuminates a detector array. The detectors of the array are associated with random numbers values. Detection of a photon by one of the detectors yields a number whose value is equal to that associated with the detector. This procedure is repeated to produce sequences of true random numbers. The randomness of the numbers stems from the transverse spatial distribution of the detection probability of the photons in the beam. If the array comprises two detectors, the true random numbers produced are binary numbers. The process can be sped up using an array having pairs of two detectors. Using an array having more than two detectors also allows generating true random numbers of dimension higher than two. The primary object of the invention is to allow generating true random numbers by way of a quantum optics process.

1 . An apparatus for generating true random numbers by way of a quantum optic process, the apparatus comprising: 
 a light source,    a detector array of single-photon detectors, and    electronic circuitry,    wherein the light source produces a beam of photons which propagate along a beam propagation direction to illuminate the detector array, and wherein the detections of the detector array generate true random number values which are registered by the electronic circuitry.    
   
   
       2 . The apparatus according to  claim 1 , wherein the light source is a light emitting diode.  
   
   
       3 . The apparatus according to  claim 1 , wherein the light source is a laser diode.  
   
   
       4 . The apparatus according to  claim 1 , wherein the beam comprises a single-mode of the electromagnetic field.  
   
   
       5 . The apparatus according to  claim 1 , wherein the beam comprises several modes of the electromagnetic field.  
   
   
       6 . The apparatus according to  claim 1 , wherein the single-photon detectors in the detector array are avalanche photodiodes.  
   
   
       7 . The apparatus according to  claim 1 , wherein the detector array comprises an array of waveguides guiding the light to single-photon detectors.  
   
   
       8 . The apparatus according to  claim 1 , wherein the detector array comprises two single-photon detectors.  
   
   
       9 . The apparatus according to  claim 1 , wherein the detector array is positioned substantially perpendicular to the beam.  
   
   
       10 . The apparatus according to  claim 1 , wherein the detector array are positioned within a plane that forms an angle different from 90 degrees with the beam propagation direction.  
   
   
       11 . The apparatus according to  claim 8 , wherein detection of a photon by one of the two single-photon detectors is associated with a binary number.  
   
   
       12 . The apparatus according to  claim 11 , wherein sequences of true random binary numbers are produced by consecutive detections of photons by the single-photon detectors of the array.  
   
   
       13 . The apparatus according to  claim 1 , wherein the detector array comprises more than two single-photon detectors.  
   
   
       14 . The apparatus according to  claim 13 , wherein detection of a photon by one of the single-photon detectors of the array is associated with an x-nary number where x equals the number of detectors in the array.  
   
   
       15 . The apparatus according to  claim 13 , wherein the detectors in the detector array are grouped in y groups of x detectors, where y is an integer greater or equal to 1 representing the number of groups of detectors and x equals the number of detectors in a group, and wherein detection of a photon by one of the single-photon detectors of one group of detectors of the array is associated with an x-nary number.  
   
   
       16 . The apparatus according to  claim 14 , wherein sequences of true random numbers are generated by consecutive detections of photons by the single-photon detectors of the array.  
   
   
       17 . A method for generating true random numbers by way of quantum optic process using a light source to produce a beam, comprising the steps of: 
 (a) illuminating a detector array of single-photon detectors;    (b) detecting a photon using at least two detectors of the array, the detection or non-detection being associated with a value, the detected values generating random numbers values, to yield a number whose value is equal to that associated with the detector;    (c) repeating the above two steps to produce sequences of true random numbers,    (d) using electronic circuitry, registering random numbers associated with the detections in a format suitable for interfacing with a computer or another device; and    (e) optionally, processing the sequences so generated to remove a possible bias, to produce numbers in a different dimension, or to tailor the probability distribution.    
   
   
       18 . The method of  claim 17  wherein the method includes the additional step of queuing the sequences of random numbers so generated for randomized distribution to recipients as seeds or as cryptography keys, in a secure manner.  
   
   
       19 . The method of  claim 17 , wherein the value associated with each detector is determined using a wave function which describes the probability density of the position of a photon in the beam, calculating the spatial detection probability of a photon in a detector, wherein, if several single-photon detectors are placed on a plane perpendicular to the beam, their respective photon detection probability is related to a value taken from the wavefunction at their location.