In our modern society random number generators are widely circulated. Numerical simulations, the gambling industry, authentication tasks like the generation of pin/tan numbers all the way to cryptographic environments are applications for random number generators. Today algorithmic or physical deterministic approaches are used, which cannot produce true random numbers. The indeterminacy and unpredictability in quantum mechanics however provide the possibility to generate true random numbers. In this work a random number generator is developed using quantum mechanical e ects. The random source is based on the light emission of a light emitting diode. The emitted photons are detected by a photomultiplier tube. The random bit values are extracted by counting the number of photons detected in a certain time interval. Both the photon emission process of the LED, the detection process and the electronical pulse recognition circuit are considered in developing the theoretical model. It turns out that the main contributions to the nal detected photon number distribution come from a coulomb blockade e ect of electrons inside the semiconductor junction of the LED, the optical attenuation of the photons and the dead time of the detection circuitry. Remarkably the e ect of the dead time modi es the photon statistics in such a way that equally distributed random bit sequences can be generated even at low mean photon numbers. In case of a Poissonian statistics this would require an in nitely high photon number. In a compact experimental setup this theoretical model can be veri ed. Random bit rates of up to 50 MBit/s can be generated. A nal analysis of bit sequences with statistical methods do not reveal any regularities in these sequences. In future this random number generator will be integrated into the quantum key distribution setup of the LMUMunich. An increase in the generation rate by scaling the setup would allow to adopt this system in modern cryptographic applications with rates of up to 1 GBit/s.
In our modern society random number generators are widely circulated. Numerical simulations, the gambling industry, authentication tasks like the generation of pin/tan numbers all the way to cryptographic environments are applications for random number generators. Today algorithmic or physical deterministic approaches are used, which cannot produce true random numbers. The indeterminacy and unpredictability in quantum mechanics however provide the possibility to generate true random numbers. In this work a random number generator is developed using quantum mechanical e ects. The random source is based on the light emission of a light emitting diode. The emitted photons are detected by a photomultiplier tube. The random bit values are extracted by counting the number of photons detected in a certain time interval. Both the photon emission process of the LED, the detection process and the electronical pulse recognition circuit are considered in developing the theoretical model. It turns out that the main contributions to the nal detected photon number distribution come from a coulomb blockade e ect of electrons inside the semiconductor junction of the LED, the optical attenuation of the photons and the dead time of the detection circuitry. Remarkably the e ect of the dead time modi es the photon statistics in such a way that equally distributed random bit sequences can be generated even at low mean photon numbers. In case of a Poissonian statistics this would require an in nitely high photon number. In a compact experimental setup this theoretical model can be veri ed. Random bit rates of up to 50 MBit/s can be generated. A nal analysis of bit sequences with statistical methods do not reveal any regularities in these sequences. In future this random number generator will be integrated into the quantum key distribution setup of the LMUMunich. An increase in the generation rate by scaling the setup would allow to adopt this system in modern cryptographic applications with rates of up to 1 GBit/s.
This paper proposes and demonstrates an optical quantum random number generator based on distribution of single photon pulse amplitude of a photomultiplier tube.The light emitted from ultraviolet LED is attenuated into discrete single photon sequence.After these photons are detected by the photomultiplier tube,the single-photon pulses with random distribution are output.Digital values of peaks of these single-photon pulses are used as the entropy sources of random number generation.In order to reduce the bias of the raw extracted random number,the SHA-256 post processing method based on FPGA is proposed and implemented.When our designed quantum random number generator works at a counting rate of 500kc/s,7random bits can be extracted on average per detected photon,and a random number generation rate of 3.5Mbit/s is obtained.The random bit sequences are tested by random number test programs ENT and STS.The test results show that the generated random bit sequences fully meet the standards of true random numbers.
Random numbers are fundamental elements in different fields of science and technology such as computer simulation like Monte Carlo-method simulation, statistical sampling, cryptography, games and gambling, and other areas where unpredictable results are necessary. Random number generators (RNG) are generally classified as “pseudo”-random number generators (PRNG) and "truly" random number generators (TRNG). Pseudo random numbers are generated by computer algorithms with a (random) seed and a specific formula. The random numbers produced in this way (with a small degree of unpredictability) are good enough for some applications such as computer simulation. However, for some other applications like cryptography they are not completely reliable. When the seed is revealed, the entire sequence of numbers can be produced. The periodicity is also an undesirable property of PRNGs that can be disregarded for most practical purposes if the sequence recurs after a very long period. However, the predictability still remains a tremendous disadvantage of this type of generators. Truly random numbers, on the other hand, can be generated through physical sources of randomness like flipping a coin. However, the approaches exploiting classical motion and classical physics to generate random numbers possess a deterministic nature that is transferred to the generated random numbers. The best solution is to benefit from the assets of indeterminacy and randomness in quantum physics. Based on the quantum theory, the properties of a particle cannot be determined with arbitrary precision until a measurement is carried out. The result of a measurement, therefore, remains unpredictable and random. Optical phenomena including photons as the quanta of light have various random, non-deterministic properties. These properties include the polarization of the photons, the exact number of photons impinging a detector and the photon arrival times. Such intrinsically random properties can be exploited to generate truly random numbers. Silicon (Si) is considered as an interesting material in integrated optics. Microelectronic chips made from Si are cheap and easy to mass-fabricate, and can be densely integrated. Si integrated optical chips, that can generate, modulate, process and detect light signals, exploit the benefits of Si while also being fully compatible with electronic. Since many electronic components can be integrated into a single chip, Si is an ideal candidate for the production of small, powerful devices. By complementary metal-oxide-semiconductor (CMOS) technology, the fabrication of compact and mass manufacturable devices with integrated components on the Si platform is achievable. In this thesis we aim to model, study and fabricate a compact photonic quantum random number generator (QRNG) on the Si platform that is able to generate high quality, "truly" random numbers. The proposed QRNG is based on a Si light source (LED) coupled with a Si single photon avalanche diode (SPAD) or an array of SPADs which is called Si photomultiplier (SiPM). Various implementations of QRNG have been developed reaching an ultimate geometry where both the source and the SPAD are integrated on the same chip and fabricated by the same process. This activity was performed within the project SiQuro—on Si chip quantum optics for quantum computing and secure communications—which aims to bring the quantum world into integrated photonics. By using the same successful paradigm of microelectronics—the study and design of very small electronic devices typically made from semiconductor materials—, the vision is to have low cost and mass manufacturable integrated quantum photonic circuits for a variety of different applications in quantum computing, measure, sensing, secure communications and services. The Si platform permits, in a natural way, the integration of quantum photonics with electronics. Two methodologies are presented to generate random numbers: one is based on photon counting measurements and another one is based on photon arrival time measurements. The latter is robust, masks all the drawbacks of afterpulsing, dead time and jitter of the Si SPAD and is effectively insensitive to ageing of the LED and to its emission drifts related to temperature variations. The raw data pass all the statistical tests in national institute of standards and technology (NIST) tests suite and TestU01 Alphabit battery without a post processing algorithm. The maximum demonstrated bit rate is 1.68 Mbps with the efficiency of 4-bits per detected photon. In order to realize a small, portable QRNG, we have produced a compact configuration consisting of a Si nanocrystals (Si-NCs) LED and a SiPM. All the statistical test in the NIST tests suite pass for the raw data with the maximum bit rate of 0.5 Mbps. We also prepared and studied a compact chip consisting of a Si-NCs LED and an array of detectors. An integrated chip, composed of Si p+/n junction working in avalanche region and a Si SPAD, was produced as well. High quality random numbers are produced through our robust methodology at the highest speed of 100 kcps. Integration of the source of entropy and the detector on a single chip is an efficient way to produce a compact RNG. A small RNG is an essential element to guarantee the security of our everyday life. It can be readily implemented into electronic devices for data encryption. The idea of "utmost security" would no longer be limited to particular organs owning sensitive information. It would be accessible to every one in everyday life.
A small-sized photonic quantum random number generator, easy to be implemented in small electronic devices for secure data encryption and other applications, is highly demanding nowadays. Here, we propose a compact configuration with Silicon nanocrystals large area light emitting device (LED) coupled to a Silicon photomultiplier to generate random numbers. The random number generation methodology is based on the photon arrival time and is robust against the non-idealities of the detector and the source of quantum entropy. The raw data show high quality of randomness and pass all the statistical tests in national institute of standards and technology tests (NIST) suite without a post-processing algorithm. The highest bit rate is 0.5 Mbps with the efficiency of 4 bits per detected photon.
A physical random number generator based on the intrinsic randomness of quantum mechanics is described. The random events are realized by the choice of single photons between the two outputs of a beamsplitter. We present a simple device, which minimizes the impact of the photon counters ’ noise, dead-time and after pulses. Random numbers are employed today as well for numerical simulations as for cryptography. Unfortunately computers are not able to generate true random numbers, as they are deterministic systems. Numerical pseudo-random generators rely on complexity [1]. Although such pseudo-random numbers can generally be employed for numerical computation, such as Monte-Carlo simulations, their use in cryptography, for example to generate keys, is more critical. The only way to get true random numbers, hence true security for crypto-systems, is to build a generator based on a random physical phenomenon [2,3,4]. As quantum theory is intrinsically random, a quantum process is an ideal base for a physical random number generator. The randomness of a sequence of numbers can be extensively tested, though not proven. It is thus of interest to thoroughly understand the behavior of the random process, so as to gain