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PL
W artykule omówiono realizację modułu funkcji fizycznie nieklonowalnej PUF w układach programowalnych FPGA. Ponadto przeprowadzono szczegółową analizę wpływu liczby implementowanych inwerterów na właściwości statystyczne generowanej odpowiedzi oraz wykorzystanie zasobów FPGA. Zaproponowana implementacja ma stanowić rozwiązanie typy lightweight dla celów uwierzytelniania i generacji kluczy dla rozwiązań IoT.
EN
This paper discusses the implementation of a physically unclonable function PUF module in FPGA programmable circuits. In addition, a detailed analysis of the effect of the number of implemented inverters on the statistical properties of the generated response and FPGA resource utilization was performed. The proposed implementation is intended to be a lightweight solution for authentication and key generation purposes for IoT solutions.
PL
Artykuł opisuje projekt systemu do pomiaru krótkich odcinków czasu dla układów o architekturze pikselowej, wykorzystujący przetwornik czas-cyfra w architekturze Verniera z oscylatorami pierścieniowymi. Omówione są również projekt oscylatora i wyniki symulacji postekstrakcyjnych. Docelową implementacją opracowywanego rozwiązania będą scalone układy elektroniki odczytu do pikselowych detektorów promieniowania X, których jedną z funkcji będzie pomiar czasu uderzenia cząstki w detektor i dodatkowo pomiar zdeponowanej energii.
EN
The paper describes the design of a system dedicated for a measurement of short time intervals in pixellated circuits. Ring oscillatorbased Vernier time-to-digital converter architecture is used. The design of ring oscillator is discussed, and post-extraction simulation results are also presented. The project goal is to implement the solution in integrated readout integrated circuits for pixel X-ray detectors that offer time of arrival and time over threshold measurement functionalities.
3
EN
We present a method and results of measurements of FPGA (Field Programmable Gate Array) selected timing parameters crucial in many timing sensitive applications such as precise time and frequency metrology. Two main parameters, i.e. the delay and its jitter, were evaluated for look-up-tables (delay 740 ps/jitter 1.33 ps), IO buffers (na/0.45 ps) and carry-chain multiplexers (28ps/0.153 ps) integrated in a programmable device Spartan-6 (Xilinx) which is one of most popular FPGA chips on the market now. Measurements were performed with the use of fast real-time sampling oscilloscope.
EN
A design and manufacturing of test structures for characterization of logic integrated circuits in a VeSTIC process developed in ITE, are described. Two variants of the VeSTIC processs have been described. A role and sources of the process variability have been discussed. The VeSFET I-V characteristics, the logic cell static characteristics, and waveforms of the 53-stage ring oscillator are presented. Basic parameters of the VeSFETs have been determined. The role of the process variability and of the parasitic elements introduced by the conservative circuit design, e.g. wide conductive lines connecting the devices in the circuits, have been discussed. Based on the inverter layout and on the process specification, the parasitic elements of the inverter equivalent circuit have been extracted. The inverter propagation times, the ring oscillator frequency, and their dependence on the supply bias have been determined.
EN
In this paper, the application of the Artificial Neural Network (ANN) algorithm has been used for testing selected specification parameters of voltage-controlled oscillator. Today, mixed electronic circuits specification time is an issue. An analog part of Phase Locked Loop is a voltage-controlled oscillator, which is very sensitive to variation of the technology process. Fault model for the integrated circuit voltage control oscillator (VCO) in ring topology is introduced and the before test stage classificatory is designed. In order to reduce testing time and keep the specification accuracy (approximation) on the high level, an artificial neural network has been applied. The features selection process and output coding for specification parameters are described. A number of different ANN have been designed and then compared with real specification of the VCO. The results obtained gives response in short time with high enough accuracy.
EN
Nowadays modern cryptographic systems require a tremendous amount of keys. Very fast random number generators (RNGs) are needed to produce those keys in the requested time, but what to do when a solution that is already in use reaches the maximum speed? The aim of the paper is to find the answer to this question. In addition, generated random numbers should not leave a cryptographic system, because according to the Kerckhoffs thesis, the security of the whole system should be based only on a key. The cryptographic system should be enclosed within a single chip. In order to check new ideas and prove them, there were used NIST 800-22 test suite and restarts mechanism. The basic concept of the generator built of ring oscillators is still the same; ring oscillators are combined by XOR gates tree. A single ring oscillator consists of inverter, latch and NAND. This kind of construction provides a tool to make synchronous start and stop of all oscillators and the restart mechanism technique is applied in this manner. The speed of generation was increased by using multiple parallel generator trees to generate instantly the whole n-bit word. The paper shows that reproduction of the base structure is not a simple method of increasing the speed of generator. Moreover, it is always important to carefully consider all new ideas, because even if the NIST statistical test suite is passed, there is a chance that the restart mechanism will show some correlations that can be used during attack on the system.
EN
In cryptography, we require that a random sequence should have excellent statistical properties as well as non-deterministic character. Combining multiple independent sources of randomness using the modulo two operation, significantly improves the statistical properties of the generated sequences and also affects the accumulation of true randomness generated in the oscillator sources. This is a very promising method of producing random sequences. In this paper, we compare the implementations of the RO-based combined random generator in various FPGAs technologies offered by various manufactures (Xilinx, Altera, Lattice). In this research, we used a NIST 800-22 statistical test suite to assess the statistical properties. The results show that the method of producing strings with a combined generator is the method stable in terms of technology. The results are similar for implementation in all FPGA used in the experiment. So, the proposed generator can be implemented in various programmable structures together with other components of a cryptographic system.
EN
In cryptography, sequences of numbers with unpredictable elements are often required. Such sequences should pass all known statistical tests for random sequences. Because sequences produced in real circuits are biased, they do not pass many statistical tests, e.g., the distribution of numbers is not uniform. Such random number sequences should be subjected to a transformation called post-processing. In this paper, a true random number generator is considered. It uses ring oscillators and the Keccak hash function as post-processing. This paper presents only simulation conditions for this approach since the post-processing part was done using x86 architecture on a PC.
PL
W pracy przedstawiono sposób wykorzystania funkcji skrótu, na przykładzie funkcji SHA-256 (ang. Secure Hash Algorithm), do poprawy właściwości statystycznych ciągów liczb losowych. W badaniach wykorzystano pakiet testów statystycznych NIST 800-22 do oceny właściwości wytwarzanego ciągu metodę restartów i test chi kwadrat, dzięki którym możliwe jest wykazanie, czy dany generator produkuje ciąg z przeważającymi elementami deterministycznymi czy niedeterministycznymi. Proponowany układ może być z powodzeniem zaimplementowany w każdym układzie FPGA (ang. Field Programmable Gate Array).
EN
Random sequences play a key role in many contemporary cryptographic systems. To increase the efficiency and robustness to attacks, it is recommended to integrate a source of random numbers with a cryptographic system using these numbers. Unfortunately, the list of non-deterministic physical phenomena available in digital circuits is rather short and practically includes jitter and metastable states. It is expected that the generator produces sequences that pass all known statistical tests and that the sequences are unpredictable and attack resistant. A generator that satisfies these expectations is named a true random number generator (TRNG). This paper presents a novel method for producing random bits with the use of jitter observed in ring oscillators. The method uses a Galois ring oscillator introduced recently and the hash function. To assess the quality of output sequences, the statistical test suite prepared by National Institute of Standards and Technology (NIST) and the restart mechanism were used. The proposed system can be implemented in any Field Programmable Gate Array (FPGA).
PL
W artykule przedstawiono wyniki analizy zmian częstotliwości oscylatora pierścieniowego, uzyskane poprzez zmianę miejsca lokowania pojedynczych bramek w różnych częściach struktury reprogramowalnej. Przeprowadzono symulacje komputerowe oraz wykonano badania eksperymentalne układu oscylatora pierścieniowego złożonego z N inwerterów, dla kilku wariantów rozmieszczenia bramek i wykorzystania linii połączeniowych pomiędzy obszarami CLBs. Układ oscylatora implementowano w strukturze FPGA (Spartan-3).
EN
This paper presents the results of investigations how the inverter location in the area of a reconfigurable FPGA chip influence the properties of a ring oscillator. Ring oscillators are very often implemented in FPGA structures, even in the very advanced projects. They are used both as a single element or an array of sensors for measuring the chip temperature and thermal verification on reconfigurable systems [1, 2], as well as for measuring the propagation delay on the internal wires of the FPGA chip [3, 4]. In our investigation the ring oscillator composed of 11 inverters was implemented in the Spartan-3 structure (Fig. 1). There were performed simulations and experiments. We tested whether and how the location of the single inverter and the delay of lines influenced the ring oscillator frequency (Figs. 2 and 3). The properties of different connections between CLBs in the FPGA structure are described (Figs. 4 and 5). The ring oscillator was located in different areas of the chip to minimize or specially increase the length of lines between the inverters (Figs. 6, 7 and 8). The simulation and experiment results are presented in Tab. 1 and discussed. In conclusion we can state that when one wants to use a ring oscillator as a sensor and to analyze the frequency or delay times, there should be considered not only the influence of temperature or voltage supply of the chip core [8] but also the location of the sensor. In the case of an array of sensors, each ring oscillator should be analyzed and calibrated independently.
PL
W artykule przedstawiono system pomiarowy, w którym nadrzędną rolę sprawuje mały, cieszący się coraz większą popularnością, mikrokomputer edukacyjny Raspberry Pi. System zaprojektowany został do wizualizacji rozkładu temperatury wewnątrz struktury układu reprogramowalnego FPGA, na podstawie dokonanych pomiarów częstotliwości oscylatorów pierścieniowych zaimplementowanych wewnątrz układu. Sterowanie procesem pomiarowym, akwizycja danych i prezentacja wyników nadzorowana jest przez mikrokomputer Raspberry Pi.
EN
In this paper the system based on Raspberry Pi, a popular educational microcomputer [1] is described. In this system, a programmable FPGA Spartan-3 XC3S200 [5] device was tested. The Raspberry Pi worked as a control unit for the whole system (Fig. 1). A part of the system was implemented inside the tested structure (Fig. 2). It was an array of ring oscillators (Fig. 3), as temperature sensors, with a structure for controlling the ring oscillators. Simple ring oscillators are often implemented in FPGA devices. They are used both as a single element or an array of sensors for measuring the chip temperature [2, 3, 4]. The frequency of the activated sensor was measured outside by an oscilloscope (SCPI command was used). The frequency was dependent on temperature. The sensors can be located in different areas of a chip [6, 7]. In case of the tested device 36 sensors were used, but generally it depends on a tested device [8, 9]. The Raspberry Pi controlled the measurement process via an SPI serial interface. The results were collected from the oscilloscope via a UART/RS232 serial interface. The relation between frequency and temperature (Fig. 4) as well as 2D visualizations (Fig. 5) were made using Gnuplot and Scilab. The results should visualize the temperature distribution inside the device, but first right calibration of sensors should be made. The location of elements inside the FPGA sensor is of great significance [10], so in the case of an array of sensors, each ring oscillator should be analyzed and calibrated independently.
EN
In cryptography we often require sequences of numbers with unpredictable elements. Such sequences cannot be produced by purely deterministic systems. A novel method for producing true randomness and increasing the randomness of a combined TRNG using ring oscillators is described. In this paper we show that the proposed method provides similar results for generators implemented using different technologies offered by Xilinx. Thus, the proposed generator can be implemented in different FPGAs with other elements of a cryptographic system.
PL
W kryptografii często wymaga się ciągów liczb złożonych z nieprzewidywalnych elementów. Takie sekwencje nie mogą być wytwarzane w systemach czysto deterministycznych. Inżynierowie muszą opracować źródła losowości, których właściwości muszą być ocenione i potwierdzone przez niezależne badania, przynajmniej doświadczalnie. W artykule pokazano, że proponowana metoda wytwarzania losowości jest stabilna pod względem technologicznym. Uzyskano bardzo zbliżone rezultaty dla generatorów losowych zrealizowanych w strukturach FPGA (Field Programmable Gate Array) wykonanych w różnych technologiach jakie oferuje firma Xilinx. W żadnym przypadku nie korzystano z manualnego rozmieszczania elementów w matrycy FPGA, aby uzyskać lepsze rezultaty. Położenie poszczególnych składników zależało tylko od oprogramowania dostarczanego przez producenta. Zatem proponowany generator może być implementowany w różnych układach FPGA razem z innymi elementami systemu kryptograficznego.
EN
One of the sources of randomness for a random bit generator (RBG) is jitter present in rectangular signals produced by ring oscillators (ROs). This paper presents a novel approach for the design of delays used in these oscillators. We suggest using delay elements made on carry4 primitives instead of series of inverters or latches considered in the literature. It enables the construction of many high frequency ring oscillators with different nominal frequencies in the same field programmable gate array (FPGA). To assess the unpredictability of bits produced by RO-based RBG, the restarts mechanism, proposed in earlier papers, was used. The output sequences pass all NIST 800-22 statistical tests for smaller number of ring oscillators than the constructions described in the literature. Due to the number of ROs with different nominal frequencies and the method of construction of carry4 primitives, it is expected that the proposed RBG is more robust to cryptographic attacks than RBGs using inverters or latches as delay element.
EN
The paper describes structure and simulation results of the novel ring oscillator designed in UMC CMOS 0.18 μm (1.8 V) which is a part of power management system including Temperature-Controlled Oscillator. Frequency generated by the oscillator is tuned by scaling the supply voltage, additionally ring length is digitally controlled. Presented ring oscillator has very wide tuning range (250 MHz–2.1 GHz) with small current consumption (34–689 μA).
PL
Artykuł opisuje strukturę i wyniki symulacji oscylatora pierścieniowego zaprojektowanego w technologii UMC CMOS 0,18 μm (1,8 V), który jest częścią systemu zarządzania mocą układu scalonego zawierającego generator przestrajany temperaturą układu. Częstotliwość generowana przez oscylator jest przestrajana poprzez zmianę napięcia zasilania, dodatkowo długość pierścienia oscylatora jest kontrolowana sygnałem cyfrowym. Opisywany oscylator ma bardzo szeroki zakres przestrajania (250 MHz–2,1 GHz) przy niskim poborze prądu (34–689 μA).
PL
W artykule przedstawiono wyniki eksperymentów, w których testowano działanie oscylatora pierścieniowego zaimplementowanego w układach reprogramowalnych. Analizowano właściwości opóźniające inwerterów zaprogramowanych w strukturze CPLD układów XC2C32 (Xilinx). W temperaturze otoczenia (300 K) i w temperaturze ciekłego azotu (77 K), badano zdolność do generacji drgań, stałość częstotliwości oscylatora (na podstawie pomiarów średniookresowych), wpływ zmian napięcia zasilania na częstotliwość oscylacji.
EN
In this paper the results of experiments with a ring oscillator implemented in programmable devices (XC2C32 Xilinx) are presented. The examined devices were immersed in a Dewar flask (Fig. 1) with liquid nitrogen. It was found out that the ring oscillator (composed of 11 gates) (Fig. 2) still worked properly in such low temperature. According to the theory of silicon semiconductors, the activity of carriers increases in low temperatures, so there was expected decrease in the propagation delay for every gate and increase in the oscillation frequency. The output frequency was measured and the average propagation time for inverters was calculated. The results at 77 K (temperature of liquid nitrogen) were compared with those at 300 K (room temperature) (Tab. 1). The output frequency characteristics versus the supply voltage for the examined devices were measured and drawn (Figs. 3 and 4). The quadric polynominal functions which fit these non-linear characteristics were proposed. The relative change of the oscillation frequency versus the supply voltage is shown in Fig. 5. The frequency sensitivity depends both on supply voltage and temperature. The relative sensitivity (normalized) in relation to the voltage at 300 K and 77 K is presented in Fig. 6. Based on the results from 24-hour measurements (86400 samples were collected) the frequency stability was determined. The average value and standard deviation value were calculated (Tab. 2) but first and foremost there was calculated and plotted the Allan deviation (Fig. 7).
16
Content available Losowość generatora TRNG zaimplementowanego w FPGA
PL
Random Number Generator) zbudowanego z wielu niezależnych generatorów pierścieniowych zaimplementowanych w tym samym układzie FPGA. Wykorzystując nową metodę odróżniania losowości od pseudolosowości wykazano, że zmniejszenie częstotliwości próbkowania wyjścia generatora pierścieniowego może zwiększyć losowość ciągu wytwarzanego przez generator TRNG. Otrzymany wynik oznacza, że generator może dostarczyć ciągów losowych użytecznych w kryptografii z większą szybkością od tej obserwowanej dla większej częstotliwości próbkującej.
EN
One of the simplest sources of purely digital true random bit sequences is the ring oscillator with output sampled by a signal coming from a low-frequency quartz oscillator. Combining XOR bit streams produced by many such generators (see Fig. 1) can significantly improve the statistical properties of the output sequence. As it is shown in the literature, this statement is true for deterministic and non-deterministic sources of random numbers. In cryptography, a user needs sequences with very good statistical properties but originating from a non-deterministic system. Therefore a method for distinguishing pseudo and true randomness for sequences produced by a combined true random number generator (TRNG) is necessary. In this paper the authors show that even a small amount of true randomness, present in a single ring oscillator, accumulates as a function of the number of ring oscillators used to produce the output stream. There is experimentally proved that in a real field programmable gate array (FPGA), the amount of randomness offered by the generator of Fig. 2 can be greater for smaller sampling frequency. Fig. 3 illustrates the behaviour of parameter mmin introduced in [6] as a function of the number K of source generators for four sampling frequencies fL: 100 MHz, 150 MHz, 200 MHz, and 250 MHz. The basic result of this paper is the statement that the efficient bit rate of streams useful for cryptography can be greater for smaller sampling frequencies than that observed for greater sampling frequencies.
PL
W pracy przedstawiono wyniki badań generatora losowego łączonego, zbudowanego z generatorów wykorzystujących generatory pierścieniowe. Wykazano, że po zaimplementowaniu generatora w układzie Virtex-5 ciągi wyjściowe spełniają wszystkie testy statystyczne z pakietu NIST 800-22. Rozważono trzy sposoby realizacji opóźnienia występującego w generatorze pierścieniowym: w postaci kaskady negatorów, kaskady przerzutników oraz za pomocą linii opóźniającej wbudowanej w układ Virtex-5. Przedstawiono ograniczenia wykorzystania proponowanego generatora w kryptografii.
EN
One of the simplest sources of purely digital true random bit sequences is a ring oscillator with output sampled by a signal from the low-frequency quartz oscillator (Fig. 1). The frequency fH is normally at least several times greater than the frequency fL. The same idea was used in the experiment conducted but there was assumed that the ring oscillators had frequencies , close to fL but not smaller than fL. The signal of frequency fL, common for all source generators, was produced by the quartz oscillator built into evaluation board ML505 containing Virtex-5 (Fig. 2). There was assumed that . The frequencies satisfy the condition . Generators that failed to satisfy this condition were reconstructed to meet this requirement, e.g., by changing the location of elements in the FPGA structure. Tables 1, 3, and 5 lists the results of NIST statistical testing for the realised generator composed of 40 source generators. The all tests were satisfactory independently of the hardware solution of the delay ?. In experiments there were considered three constructions for ?: a chain of inverters, a chain of latches and the delay line built into Virtex-5. The practical RNG demonstrates that the idea of combining modulo 2 of a finite number of source streams can be used to construct entirely digital, high-speed RNGs that pass all NIST statistical tests. The application of this type of generator to cryptography, considered in the last paragraph of this paper, although possible, requires further research.
PL
W pracy przedstawiono projekt i wyniki symulacji po ekstrakcji z topografii generatora pierścieniowego wykonanego w technologii AMS 0,35 pm przestrajanego w zakresie od 50 kHz do 2 GHz, moc strat nie przekracza 5,3 mW przy napięciu zasilania 3,3 V, poziom szumów fazowych dla częstotliwości podstawowej 900 MHz i przesunięciu 1 MHz wynosi -87,4 dBc/Hz, głównym przeznaczeniem układu jest taktowanie systemów cyfrowych testowanych pod kątem zjawisk termicznych i elektrotermicznych
EN
The objective of this paper is to present a design and post-layout simulation results of a voltage-controlled ring oscillator designed in AMS 0.35 pm technology retuned from 50 kHz to 2 GHz. A power dissipation does not exceed 5.3 mW for a voltage supply 3.3 V, a single-sideband noise at the offset frequency 1 MHz from the carrier frequency 900 MHz is - 87.4 dBc/Hz. The project can be applied as a clock signal generator in research and development of digital systems in terms of thermal and electrothermal phenomena
PL
Łączenie liczb losowych wytwarzanych przez wiele niezależnych generatorów może znacząco poprawić właściwości statystyczne ciągu wyjściowego. To stwierdzenie jest prawdziwe dla deterministycznych i niedeterministycznych źródeł ciągów losowych. W kryptografii użytkownik często potrzebuje ciągów o bardzo dobrych właściwościach statystycznych, lecz pochodzących z systemu niedeterministycznego. W pracy przedstawiamy wyniki testów statystycznych przeprowadzonych dla ciągów liczb wytwarzanych przez generator łączony. Proponujemy nową metodę odróżniania pseudolosowości i losowości dla ciągów wytwarzanych przez generator liczb prawdziwie losowych (TRNG). Generator ten wykorzystuje generatory pierścieniowe, których wyjścia są próbkowane przez sygnał innego generatora. Badany generator wykonano w układzie reprogramowalnym FPGA wytwarzanym przez firmę Xilinx.
EN
Combining random numbers produced by many independent generators can significantly improve the statistical properties of the output sequence. This statement is true for deterministic and non-deterministic sources of random numbers. In cryptography, a user often needs sequences with very good statistical properties but originating from a non-deterministic system. In this paper, we present the results of statistical tests performed for number sequences produced by a combined generator. We propose a new method for distinguishing pseudo and true randomness for sequences produced by a true random number generator (TRNG). The generator uses ring oscillators with outputs sampled by a signal of another clock. The combined TRNG was realized in a field programmable gate array (FPGA) produced by Xilinx.
PL
Zaprezentowano nanoczułe mikrosondy krzemowe do pomiaru wielkości mechanicznych, w których do detekcji odkształcenia wykorzystano oscylatory pierścieniowe CMOS, zintegrowane z mikrobelką krzemową. Efekt piezorezystywności powoduje, iż odkształcenie belki zmienia parametry tranzystorów MOS, co z kolei wpływa na częstotliwość rezonansową oscylatora pierścieniowego. Zintegrowane mikrosondy wykonano w technologii CMOS 3,5 µm z bramką polikrzemową i jednym poziomem metalizacji. W części mikromechanicznej posłużono się techniką reliefu do uformowania bardzo cienkich belek o grubości 3...4 µm. Osiągnięto czułość 5...8 Hz/nm przy początkowej częstotliwości rezonansowej oscylatora ~10,8 MHz.
EN
Silicon microprobes for nanosensitive mechanical measurements are presented. They consist of the silicon microbeams, which are integrated with the CMOS ring oscillators. Piezoresistivity phenomenon is responsible for the MOS transistor parameter changes under mechanical stress. In consequence, the ring oscillator consisting of stressed MOS transistors gives resonant frequency shift. Integrated microprobes were fabricated with use of standard 3.5 µm CMOS technology, with one polysilicon layer and one metal level. Micromechanical part of technology was based on the relief technique, enabling 3.. .4 µm thick beams formation. With initial (no stress) resonant frequency about 10.8 MHz of the ring oscillator, beam deflection sensitivity 5...8 Hz/nm was obtained.
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