A simple experimental setup to produce true random numbers is described. The experiment involves measuring successive times between decays of a radioactive source. We discuss two different ways of comparing these times: one that generates a string of random zeros and ones, and another that produces numbers derivable from the permutation group. It is shown that the methods used in the experiment produce the same results for any random process and can therefore be used as a test for randomness in other physical systems.
A simple experimental setup to produce true random numbers is described. The experiment involves measuring successive times between decays of a radioactive source. We discuss two different ways of comparing these times: one that generates a string of random zeros and ones, and another that produces numbers derivable from the permutation group. It is shown that the methods used in the experiment produce the same results for any random process and can therefore be used as a test for randomness in other physical systems.
Efficient and reliable Random Number Generator (RNG) are increasingly demanded in cryptographic applications, such as on-the-fly data encription/decription and as a general tool for data protection. Main requirement of RNG is a true randomness, which is achievable by means of physical randomness sources only. A True-RNG based on two independent Stochastic Processes (SP) is presented and discussed. As primary randomness sources, two radioactive decay processes are used. A radioactive source has many advantages over others noise sources, since the decay rate of any nuclide does not depend on temperature, chemical composition, physical state, environmental conditions, and aging. In addition, in U ore for example, the various nuclides are, at very good approximation, at equilibrium in the decay chain, so that many stationary independent SP's with the same statistics can be simply obtained by detecting and selectively routing, e.g. by pulse amplitude sorting, gamma rays of different energy emitted by different nuclides in the decay chain. Simulation is performed by a numerical code. The random bit stream obtained is tested for randomness by the NIST test suite, and results are shown. A hardware implementation of the system is also presented.
Randomness is a phenomena which we are confronted with all the time. Will it rain today? Will the train be on time? What present(s) will I receive at Christmas? But are such phenomena truly random?Good randomness is essential for many applications. For instance, cryptography, the art of hiding information from malicious parties, is only as good as the sources of randomness that underlie it. Quantum mechanics, the theory of microscopic phenomena, can only predict the probability of events. For instance quantum theory can only predict the probability that a radioactive nucleus will decay, not when the nucleus will decay. Does this mean that microscopic phenomena are truly random?By studying systems of two entangled particles, it can be shown both theoretically and experimentally that events at the microscopic scale are truly random, truly unpredictable. Beyond its philosophical implications, this result also has important potential applications. Indeed it implies that one can build random number generators whose output is random and certifies that the device works correctly. That is, if the random number generator malfunctions in some way, if the numbers it produces cease to be random, this will automatically be detected. By extending this idea, one could also build quantum cryptographic systems and quantum computers that certify that they work correctly. We discuss the perspectives for practical implementations.
Random number generators are indispensable for a multi- tude of tasks; from electronic games to secure communications. Most gen- erators have been made either in software or determinist hardwired de- vices such as the Linear-Feedback-Shift-Registers; while gaining in costs or speed, the “random” sequences generated are actually deterministic, obeying clear generating algorithms, despite all randomness appearance of their outputs. From the other side, Nature presents a multitude of sources of true randomness that can be explored. Commercial random generators exist based on physical processes as the source of randomness. Difficulties are always present to extract Nature’s randomness. This paper presents guidelines for construction of a fast (telecommunication speed) Physical Random Number Generator. It discusses the fundamental physical ele- ments involved, technicalities of signal recording and its limitations, and the final bit extraction. The need for randomness tests is emphasized and the impossibility of guaranteeing true randomness of a finite sequence is discussed.
Pseudo-random number generators are widely used in many branches of science, mainly in applications related to Monte Carlo methods, although they are deterministic in design and, therefore, unsuitable for tackling fundamental problems in security and cryptography. The natural laws of the microscopic realm provide a fairly simple method to generate non-deterministic sequences of random numbers, based on measurements of quantum states. In practice, however, the experimental devices on which quantum random number generators are based are often unable to pass some tests of randomness. In this review, we briefly discuss two such tests, point out the challenges that we have encountered and finally present a fairly simple method that successfully generates non-deterministic maximally random sequences.
Pseudo-random number generators are widely used in many branches of science, mainly in applications related to Monte Carlo methods, although they are deterministic in design and, therefore, unsuitable for tackling fundamental problems in security and cryptography. The natural laws of the microscopic realm provide a fairly simple method to generate non-deterministic sequences of random numbers, based on measurements of quantum states. In practice, however, the experimental devices on which quantum random number generators are based are often unable to pass some tests of randomness. In this review, we briefly discuss two such tests, point out the challenges that we have encountered in experimental implementations and finally present a fairly simple method that successfully generates non-deterministic maximally random sequences.
We describe an experimental setup involving a single radioactive atom which decays in unit time with probability ½, but such that it is possible to successfully predict whether the atom decays with probability greater than ½. We also describe a strategy which correctly predicts with probability greater than ½ which of two radioactive atoms is more likely to decay in unit time, given that we can only observe one of the two species. These ideas are mathematical in nature but are very likely to have applications in physics as well as other areas.