Optimising and evaluating designs for reconfigurable hardware

Growing demand for computational performance, and the rising cost for chip design and manufacturing make reconfigurable hardware increasingly attractive for digital system implementation. Reconfigurable hardware, such as field-programmable gate arrays (FPGAs), can deliver performance through parallelism while also providing flexibility to enable application builders to reconfigure them. However, reconfigurable systems, particularly those involving run-time reconfiguration, are often developed in an ad-hoc manner. Such an approach usually results in low designer productivity and can lead to inefficient designs. This thesis covers three main achievements that address this situation. The first achievement is a model that captures design parameters of reconfigurable hardware and performance parameters of a given application domain. This model supports optimisations for several design metrics such as performance, area, and power consumption. The second achievement is a technique that enhances the relocatability of bitstreams for reconfigurable devices, taking into account heterogeneous resources. This method increases the flexibility of modules represented by these bitstreams while reducing configuration storage size and design compilation time. The third achievement is a technique to characterise the power consumption of FPGAs in different activity modes. This technique includes the evaluation of standby power and dedicated low-power modes, which are crucial in meeting the requirements for battery-based mobile devices

Reconfigurable Architectures for Cryptographic Systems

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