Compact quantum random number generator based on superluminescent light-emitting diodes.

We propose and implement a simple and compact quantum random number generation (QRNG) scheme based on the quantum phase fluctuations of a DFB laser. The distribution probability of the experimentally measured data fits well with the simulation result, got from the theoretical model we established. Min-entropy estimation and Toeplitz-hashing randomness extractor are used to obtain the final random bit. The proposed approach has advantages not only in simple structure but also in high random bit generation rate. As a result, 502 Gbits/s random bits generation speed can be obtained, which is much higher than previous similar schemes. This approach offers a possibility to promote the practical application of QRNG.

A true random number generator (TRNG) is suitable for generating secure keys and nonces. TRNGs implemented in IoT devices must be small in scale and have low power consumption. The random number sequence generated by TRNG needs to have high entropy immediately after startup and a stable state. In this paper, three types of ring oscillator type TRNGs, TERO-based, COSO-based, and STR-based TRNG, are implemented on Zynq-7010. When these TRNGs are implemented as a single entropy source, it is challenging to implement them because it is necessary to evaluate the layout and wiring for each FPGA. This paper proposes a TRNG configuration, which exclusively ORs the outputs of multiple entropy sources. We show that this configuration can reduce the implementing difficulty and realize high entropy. For the random number sequence evaluation, we use the statistical test of NIST SP800-90B and BSI AIS 20/31. In addition, the random number sequence immediately after the startup is also statistically evaluated. As a result, our proposed TRNGs generate high entropy random numbers and are easy to implement on FPGA when we implement TRNGs with eight single entropy sources for TERO-based TRNG, 48 for COSO-based TRNG, and two for STR-based TRNG, respectively.

Quantum random number generator (QRNG) allows obtaining true random bit sequences. In QRNG based on quantum nature of vacuum, optical beam splitter with two inputs and two outputs is normally used. We compare mathematical descriptions of spatial beam splitter and fiber Y-splitter in the quantum model for QRNG, based on homodyne detection. These descriptions were identical, that allows to use fiber Y-splitters in practical QRNG schemes, simplifying the setup. Also we receive relations between the input radiation and the resulting differential current in homodyne detector. We experimentally demonstrate possibility of true random bits generation by using QRNG based on homodyne detection with Y-splitter.

Linear feedback shift registers (LFSRs) are essential components of communications systems such as pseudo random bit sequence (PRBS) generators, convolutional encoders, scramblers and randomizers [1, 2]. Fig.1 (left) shows a LFSR scheme in which the XOR gate is operated among two tapped bits i and i+k within the shift register. The result bit is fed to the shift register at the last position (n) and the sequence in the register is 1-bit shifted as well. The experimental setup for demonstrating an all-optical LFSR is shown in Fig.1 (middle). The main components of the scheme are an optical buffer [3], a bit selecting circuit, and a XOR gate. The data vector (A) is generated by modulating the continuous wave (CW) λ s with a 10Gbps non-return-to-zero (NRZ) electrical pattern whose period is T P =33.3168µs. Only 5 bits are used as the initial sequence for the shift register. The travelling time of the packet in the buffer is T L =1.85 µs, meaning that up to 18 round trips can be accommodated by the pattern's period T P but one of those should be preserved for erasing the buffer before it is fetched a new sequence. The initial sequence enters the buffer as well as propagates directly to the bit selecting circuit. Every round trip, a new sequence as a replica of the previous one plus the feedback bit comes out. At the last round trip, a pump signal inserted into the buffer through the circulator will strongly reduce the gain of the semiconductor optical amplifier (SOA). Both the circulating packet and the accumulating in-band amplified spontaneous emission (ASE) noise will be suppressed. The buffer is now completely cleaned for a new cycle. The first and the last bits of the 1-bit shifted sequence are selected for the XOR operation. Referring to Fig.1 (left), i=1 and k=4, n=5. With this setup, the bit selecting circuit requires 2 clock signals (C) for tap the proper bits from the incoming sequence. The sampling process is done by exploiting four-wave-mixing (FWM) in a 250m-long highly nonlinear fiber (HNLF). Since at every round trip the sequence must be 1-bit shifted, the sampling clocks must be accordingly delayed for 1 bit, resulting the clock period of T C =T L +T B where T B =100ps is the bit time. The outputs of the bit selecting circuit are fed as pump signals to port a and d of a SOA Mach Zehnder interferometer (MZI). They are synchronized with a clock at λ s used as the probe signal (F) at port b. The output of the XOR gate is then fed back into the buffer. The feedback bit should be precisely allocated at the end of the packet circulating inside the buffer, meaning that the feedback time should be T F =T L +T B +T seq in which T seq is the original sequence duration and equal to 500ps in our setup. Fig.1 (right) depicts the results at the 10th round trip for two different input initial sequences (10001) and (10011) taken at point (B). The equalization between bits in the sequence and the quality of the pulses is strongly limited by the accumulating ASE noise inside the buffer, the long fiber-based structure and the bit's polarization. The fiber-based setup also causes misalignment between the clocks, spoils the essential synchronism and degrades the performance of the FWM and the XOR operation. One possible solution for solving all of these problems and hence improving the performance is the integration approach. The bit selection could be implemented exploiting nonlinear effects into an SOA or a periodic-poled lithium niobate (PPLN) instead of using a long HLNF. Moreover the extinction ratio of the pulses at the SOA-MZI XOR output (<13.5dB) could be improved, e.g. with a saturable absorber at its output, thus increasing the number of allowed round trips into the shift register and reducing the noise on the final bit sequence.

True random number generators (TRNG) are important counterparts to pseudorandom number generators (PRNG), especially for high security applications such as cryptography. They produce unpredictable, non-repeatable random sequences. However, most TRNGs require specialized hardware to extract entropy from physical phenomena and tend to be slower than PRNGs. These generators usually require post-processing algorithms to eliminate biases but in turn, reduces performance. In this paper, a new post-processing method based on hyperchaos is proposed for software-based TRNGs which not only eliminates statistical biases but also provides amplification in order to improve the performance of TRNGs. The proposed method utilizes the inherent characteristics of chaos such as hypersensitivity to input changes, diffusion, and confusion capabilities to achieve these goals. Quantized bits of a physical entropy source are used to perturb the parameters of a hyperchaotic map, which is then iterated to produce a set of random output bits. To depict the feasibility of the proposed post-processing algorithm, it is applied in designing TRNGs based on digital audio. The generators are analyzed to identify statistical defects in addition to forward and backward security. Results indicate that the proposed generators are able to produce secure true random sequences at a high throughput, which in turn reflects on the effectiveness of the proposed post-processing method.

True random number generators (TRNG) are widely used to generate encryption keys in information security systems [1]–[2]. In TRNG, entropy source is a critical module who provides the source of randomness of output bit stream. The unavoidable electrical noise in circuit becomes an ideal entropy source due to its unpredictability. Among the methods of capturing electrical noise, ring oscillator-based entropy source makes the TRNG most robust to deterministic noise and 1/f noise which means the strongest anti-interference capability, so it is simple in structure and easy to integrate [3]. Thus, great research attention has focused on ring oscillator-based TRNGs [3] –[7]. In [4], a high-speed TRNG with 100Mbps output bit rate was proposed, but it took up too much power and area. A TRNG based on tetrahedral ring oscillator was proposed in [5]. Its power consumption was very low but the output bit rate was also very low. A ring oscillator-based TRNG with low output bit rate but high power was proposed in [7]. In a word, none of the above architectures achieve an appropriate compromise between bit rate and power consumption. This work presents a new feedback architecture of TRNG based on tetrahedral ring oscillator. The output random bit stream generates a relative random control voltage that acts on the transmission gates in oscillator through a feedback loop, thus increasing phase jitter of the oscillator and improving output bit rate. Furthermore, an XOR chain-based post-processing unit is added to eliminate the statistical deviations and correlations between raw bits.

The concept of a superluminescent light-emitting diode (SLED) was proposed for the first time. It can be briefly described as an edge-emitting semiconductor light source that operates in the so-called superluminescence regime, also known as the amplified spontaneous emission (ASE) regime. SLEDs are realized as epitaxially grown layers on a substrate in an index-guided ridge-waveguide geometry similar to Fabry–Perot-type laser diodes. A couple of different approaches exist for the modeling and simulation of SLEDs. An SLED device is assumed with a perfect front facet having zero residual reflection, similar to an ideal standard SLED, but with a back facet being a perfect reflector that reflects all incident light back into the waveguide. Commercial SLEDs have to fulfill target specifications for the electro-optical performance that are defined by the application. Generally, all approaches for the design of SLED structures showing an ASE spectrum with ultrawide emission bandwidth are based on a multitransition design.

We describe a methodology and standard of proof for experimental claims of quantum random-number generation (QRNG), analogous to well-established methods from precision measurement. For appropriately constructed physical implementations, lower bounds on the quantum contribution to the average min-entropy can be derived from measurements on the QRNG output. Given these bounds, randomness extractors allow generation of nearly perfect ``$\ensuremath{\epsilon}$-random'' bit streams. An analysis of experimental uncertainties then gives experimentally derived confidence levels on the $\ensuremath{\epsilon}$ randomness of these sequences. We demonstrate the methodology by application to phase-diffusion QRNG, driven by spontaneous emission as a trusted randomness source. All other factors, including classical phase noise, amplitude fluctuations, digitization errors, and correlations due to finite detection bandwidth, are treated with paranoid caution, i.e., assuming the worst possible behaviors consistent with observations. A data-constrained numerical optimization of the distribution of untrusted parameters is used to lower bound the average min-entropy. Under this paranoid analysis, the QRNG remains efficient, generating at least 2.3 quantum random bits per symbol with 8-bit digitization and at least 0.83 quantum random bits per symbol with binary digitization at a confidence level of 0.999 93. The result demonstrates ultrafast QRNG with strong experimental guarantees.

This paper presents a novel approach to enhancing the security and reliability of drone communications through the integration of Quantum Random Number Generators (QRNG) in Frequency Hopping Spread Spectrum (FHSS) systems. We propose a multi-drone framework that leverages QRNG technology to generate truly random frequency hopping sequences, significantly improving resistance against jamming and interception attempts. Our method introduces a concurrent access protocol for multiple drones to share a QRNG device efficiently, incorporating robust error handling and a shared memory system for random number distribution. The implementation includes secure communication protocols, ensuring data integrity and confidentiality through encryption and Hash-based Message Authentication Code (HMAC) verification. We demonstrate the system’s effectiveness through comprehensive simulations and statistical analyses, including spectral density, frequency distribution, and autocorrelation studies of the generated frequency sequences. The results show a significant enhancement in the unpredictability and uniformity of frequency distributions compared to traditional pseudo-random number generator-based approaches. Specifically, the frequency distributions of the drones exhibited a relatively uniform spread across the available spectrum, with minimal discernible patterns in the frequency sequences, indicating high unpredictability. Autocorrelation analyses revealed a sharp peak at zero lag and linear decrease to zero values for other lags, confirming a general absence of periodicity or predictability in the sequences, which enhances resistance to predictive attacks. Spectral analysis confirmed a relatively flat power spectral density across frequencies, characteristic of truly random sequences, thereby minimizing vulnerabilities to spectral-based jamming. Statistical tests, including Chi-squared and Kolmogorov-Smirnov, further confirm the unpredictability of the frequency sequences generated by QRNG, supporting enhanced security measures against predictive attacks. While some short-term correlations were observed, suggesting areas for improvement in QRNG technology, the overall findings confirm the potential of QRNG-based FHSS systems in significantly improving the security and reliability of drone communications. This work contributes to the growing field of quantum-enhanced wireless communications, offering substantial advancements in security and reliability for drone operations. The proposed system has potential applications in military, emergency response, and secure commercial drone operations, where enhanced communication security is paramount.

A reconfigurable PUF structure with dual working modes based on entropy separation model

Phase-locked loop (PLL) based true random number generator (TRNG) is very well suited for security applications using field programmable gate arrays (FPGAs) because most of FPGAs feature hardwired PLL blocks. PLL based TRNGs (PLL-TRNGs) are easy to implement and do not require manual placement or routing. The design of such TRNGs is also highly portable within the same device family. This is not the case in many other TRNG designs. However, the design of a PLL-TRNGs is not a trivial task. Due to many PLL parameters, which need to be fine tuned to achieve required security and speed requirements, an exhaustive design space exploration is practically not feasible. Thus, the designers are required to go through many trial and error cycles of manual parameter tweaking and the results are still not guaranteed to be optimal. In this paper, we use a genetic algorithm (GA) based optimization to generate a suitable configuration of the PLL-TRNG, such that it is secure and reaches high output bit rate. GA optimization allows to take into account physical limits of the PLL, such as input/output frequency, and maximum voltage controlled oscillator (VCO) frequency, which avoids invalid configurations and reduces the development time. The method has proven to be very efficient and it significantly reduces the design time without compromising the security. All the presented configurations were tested on recent FPGA families and the statistical quality of the resulting TRNG configurations was verified using the AIS 31 test suite.

A true random number generator (TRNG) is essential to ensure information security for Internet of Things (IoT) edge devices. While pseudorandom number generators (PRNGs) have been instrumental, their deterministic nature limits their application in security-sensitive scenarios. In contrast, hardware-based TRNGs derived from physically unpredictable processes offer greater reliability. This study demonstrates a peripheral-free TRNG utilizing two cascaded three-stage inverters (TSIs) in conjunction with an XOR gate composed of monolayer molybdenum disulfide (MoS2) field-effect transistors (FETs) by exploiting the stochastic charge trapping and detrapping phenomena at and/or near the MoS2/dielectric interface. The entropy source passes the NIST SP800-90B tests with a minimum normalized entropy of 0.8780, while the generated bits pass the NIST SP800-22 randomness tests without any postprocessing. Moreover, the keys generated using these random bits are uncorrelated with near-ideal entropy, bit uniformity, and Hamming distances, exhibiting resilience against machine learning (ML) attacks, temperature variations, and supply bias fluctuations with a frugal energy expenditure of 30 pJ/bit. This approach offers an advantageous alternative to conventional silicon, memristive, and nanomaterial-based TRNGs as it obviates the need for extensive peripherals while harnessing the potential of atomically thin 2D materials in developing low-power TRNGs.

A novel model is presented that accounts for amplified spontaneous emission (ASE) in super-luminescent light-emitting diodes (SLEDs) and semiconductor optical amplifiers. This model is implemented into an existing device simulator. Stimulated carrier recombination due to ASE is the mechanism that couples the electronic and the optical problems and self-consistency is guaranteed by accounting for this interaction. Based on this model, coupled electro-optical simulations (2D) are carried out to investigate the impact of quantum well carrier transport and material gain on the spectral emission properties of SLEDs. Simulated LI-curves and ASE spectra are compared to measurements. Various InP-based SLEDs with multiple quantum well active regions operating around 1300 nm are used as benchmark devices. The good agreement between simulation and measurement for different device designs demonstrates the model's validity.

True random number generation from mobile telephone photo based on chaotic cryptography

Random number generators (RNG) are essential elements in many cryptographic systems. True random number generators (TRNG) rely upon sources of randomness from natural processes such as those arising from quantum mechanics phenomena. We demonstrate that a quantum computer can serve as a high-quality, weakly random source for a generalized user-defined probability mass function (PMF). Specifically, QC measurement implements the process of variate sampling according to a user-specified PMF resulting in a word comprised of electronic bits that can then be processed by an extractor function to address inaccuracies due to non-ideal quantum gate operations and other system biases. We introduce an automated and flexible method for implementing a TRNG as a programmed quantum circuit that executes on commercially-available, gate-model quantum computers. The user specifies the desired word size as the number of qubits and a definition of the desired PMF. Based upon the user specification of the PMF, our compilation tool automatically synthesizes the desired TRNG as a structural OpenQASM file containing native gate operations that are optimized to reduce the circuit's quantum depth. The resulting TRNG provides multiple bits of randomness for each execution/measurement cycle; thus, the number of random bits produced in each execution is limited only by the size of the QC. We provide experimental results to illustrate the viability of this approach.