614 research outputs found

    Reconfigurable Architectures for Cryptographic Systems

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    Field Programmable Gate Arrays (FPGAs) are suitable platforms for implementing cryptographic algorithms in hardware due to their flexibility, good performance and low power consumption. Computer security is becoming increasingly important and security requirements such as key sizes are quickly evolving. This creates the need for customisable hardware designs for cryptographic operations capable of covering a large design space. In this thesis we explore the four design dimensions relevant to cryptography - speed, area, power consumption and security of the crypto-system - by developing parametric designs for public-key generation and encryption as well as side-channel attack countermeasures. There are four contributions. First, we present new architectures for Montgomery multiplication and exponentiation based on variable pipelining and variable serial replication. Our implementations of these architectures are compared to the best implementations in the literature and the design space is explored in terms of speed and area trade-offs. Second, we generalise our Montgomery multiplier design ideas by developing a parametric model to allow rapid optimisation of a general class of algorithms containing loops with dependencies carried from one iteration to the next. By predicting the throughput and the area of the design, our model facilitates and speeds up design space exploration. Third, we develop new architectures for primality testing including the first hardware architecture for the NIST approved Lucas primality test. We explore the area, speed and power consumption trade-offs by comparing our Lucas architectures on CPU, FPGA and ASIC. Finally, we tackle the security issue by presenting two novel power attack countermeasures based on on-chip power monitoring. Our constant power framework uses a closed-loop control system to keep the power consumption of any FPGA implementation constant. Our attack detection framework uses a network of ring-oscillators to detect the insertion of a shunt resistor-based power measurement circuit on a device's power rail. This countermeasure is lightweight and has a relatively low power overhead compared to existing masking and hiding countermeasures

    The ingenuity of common workmen: and the invention of the computer

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    Since World War II, state support for scientific research has been assumed crucial to technological and economic progress. Governments accordingly spent tremendous sums to that end. Nothing epitomizes the alleged fruits of that involvement better than the electronic digital computer. The first such computer has been widely reputed to be the ENIAC, financed by the U.S. Army for the war but finished afterwards. Vastly improved computers followed, initially paid for in good share by the Federal Government of the United States, but with the private sector then dominating, both in development and use, and computers are of major significance.;Despite the supposed success of public-supported science, evidence is that computers would have evolved much the same without it but at less expense. Indeed, the foundations of modern computer theory and technology were articulated before World War II, both as a tool of applied mathematics and for information processing, and the computer was itself on the cusp of reality. Contrary to popular understanding, the ENIAC actually represented a movement backwards and a dead end.;Rather, modern computation derived more directly, for example, from the prewar work of John Vincent Atanasoff and Clifford Berry, a physics professor and graduate student, respectively, at Iowa State College (now University) in Ames, Iowa. They built the Atanasoff Berry Computer (ABC), which, although special purpose and inexpensive, heralded the efficient and elegant design of modern computers. Moreover, while no one foresaw commercialization of computers based on the ungainly and costly ENIAC, the commercial possibilities of the ABC were immediately evident, although unrealized due to war. Evidence indicates, furthermore, that the private sector was willing and able to develop computers beyond the ABC and could have done so more effectively than government, to the most sophisticated machines.;A full and inclusive history of computers suggests that Adam Smith, the eighteenth century Scottish philosopher, had it right. He believed that minimal and aloof government best served society, and that the inherent genius of citizens was itself enough to ensure the general prosperity

    The art of solving a large number of non-stiff, low-dimensional ordinary differential equation systems on GPUs and CPUs

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    This paper discusses the main performance barriers for solving a large number of independent ordinary differential equation systems on processors (CPU) and graphics cards (GPU). With a naïve approach, for instance, the utilisation of a CPU can be as low as 4% of its theoretical peak processing power. The main barriers identified by the detailed analysing of the hardware architectures and profiling using hardware performance monitoring units are as follows. First, exploitation of the SIMD capabilities of the CPU via vector registers. The solution is to implement/enforce explicit vectorisation. Second, hiding instruction latencies on both CPUs and GPUs that can be achieved with increasing (instruction-level) parallelism. Third, the efficient handling of large timescale differences or event handling using the massively parallel architecture of GPUs. A viable option to overcome this difficulty is asynchronous time stepping. The above optimisation techniques and their implementation possibilities are discussed and tested on three program packages: MPGOS written in C++ and specialised only for GPUs; ODEINT implemented in C++, which supports execution on both CPUs and GPUs; finally, DifferentialEquations.jl written in Julia that also supports execution on both CPUs and GPUs. The tested systems (Lorenz equation, Keller–Miksis equation and a pressure relief valve model) are non-stiff and have low dimension. Thus, the performance of the codes are not limited by memory bandwidth, and Runge–Kutta type solvers are efficient and suitable choices. The employed hardware are an Intel Core i7-4820K CPU with 30.4 GFLOPS peak double-precision performance per cores and an Nvidia GeForce Titan Black GPU that has a total of 1707 GFLOPS peak double-precision performance

    Saturable absorption measurement of platinum as saturable absorber by using twin detector method based on mode-locked fiber laser

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    This paper illustrates the absorption measurement of Pt as saturable absorber (SA) by using mode-locked fiber laser system. The SA is fabricated by depositing 10 nm of Pt on the fiber ferrules using sputtering method. The absorption measurement of Pt is characterised by employing a balanced twin detector method based on mode-locked fiber laser with central wavelength of 1532.25 nm, repetition rate of 2.833 MHz and pulse duration of 34.3 ns. The Pt-SA produce modulation depth of 21.9% and saturation intensity of 21.6 MW cm-2
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