For data-intensive applications, energy expended in on-chip computation constitutes only a small fraction of the total energy consumption. The primary contribution comes from transporting data between off-chip memory and on-chip computing elements-a limitation referred to as the Von-Neumann bottleneck. In such a scenario, improving the compute energy through parallel processing or on-chip hardware acceleration brings minor improvements to the total energy requirement of the system. We note that an effective solution to mitigate the Von-Neumann bottleneck is to develop a framework that enables computing in off-chip nonvolatile memory arrays, where the data reside permanently. In this paper, we present a malleable hardware (MAHA) reconfigurable framework that modifies nonvolatile CMOS-compatible flash memory array for on-demand reconfigurable computing. MAHA is a spatio-temporal mixed-granular hardware reconfigurable framework, which utilizes the memory for storage as well as lookup table-based computation (hence malleable) and uses a low-overhead hierarchical interconnect fabric for communication between processing elements. A detailed design of the malleable hardware together with a comprehensive application mapping flow is presented. Design overheads carefully estimated at the 45-nm technology node indicate that for a set of common kernels, MAHA achieves a 91X improvement in energy efficiency over a software-only solution with negligible impact on memory performance in normal mode. The proposed design changes incur only 6% memory area overhead.

Reconfigurable hardware including Field programmable gate arrays (FPGAs) are being used in a wide range of embedded applications including signal processing, multimedia, and security. FPGA device production is often outsourced to off-shore facilities for economic reasons. This opens up the opportunities for insertion of malicious design alterations in the foundry, referred to as hardware Trojan attacks, to cause logical and physical malfunction. The vulnerability of these devices to hardware attacks raises security concerns regarding hardware and design assurance. In this paper, we analyze hardware Trojan attacks in FPGA considering diverse activation and payload characteristics and derive a taxonomy of Trojan attacks in FPGA. To our knowledge, this is the first effort to analyze Trojan threats in FPGA hardware. Next, we propose a novel redundancy-based protection approach based on Trojan tolerance that modifies the application mapping process to provide high-level of protection against Trojans of varying forms and sizes. We show that the proposed approach incurs significantly higher security at lower overhead than conventional fault-tolerance schemes by exploiting the nature of Trojans and reconfiguration of FPGA resources.

Physical Unclonable Functions (PUFs) have emerged as an attractive primitive to address diverse hardware security issues, such as chip authentication, intellectual property (IP) protection and cryptographic key generation. Existing PUFs, typically acquired and integrated in a design as a commodity, often incur considerable hardware overhead. Many of these PUFs also suffer from insufficient challenge-response pairs. In this paper, we propose ScanPUF, a novel PUF implementation using a common on-chip structure used for improving circuit testability, namely scan chain. It exploits path delay variations between the scan flip-flops in a scan chain to create high-quality (in terms of uniqueness and robustness) secret keys. Furthermore, since a scan chain provides large pool of scan paths to create a signature, we can achieve high volume of secret keys from each chip. Since it uses a prevalent on-chip structure, the overhead is extremely small (2.3% area of the RO-PUF), primarily contributed by small additional logic in the signature-generation cycle controller. Circuit-level simulation results with 1000 chips under inter- and intra-die process variations show high uniqueness of 49.9% average inter-die Hamming distance and good reproducibility of 5% intra-die Hamming distance below 85 °C. The temporal variations due to device aging effect e.g. bias temperature instability (BTI) lead to only 4% unstable bits for ten-year usage. The experimental evaluation on FPGA (Altera Cyclone-III) exhibits 47.1% average inter-Hamming distance, as well as 3.2% unstable bits at room temperature.

Many industrial systems, sensors and advanced propulsion systems demand electronics capable of functioning at high ambient temperature in the range of 500-600°C. Conventional Si-based electronics fail to work reliably at such high temperature ranges. In this paper we propose, for the first time, a high-temperature reconfigurable computing platform capable of operating at temperature of 500°C or higher. Such a platform is also amenable for reliable operation in high-radiation environment. The hardware reconfigurable platform follows the interleaved architecture of conventional Field Programmable Gate Array (FPGA) and provides the usual benefits of lower design cost and time. However, high-temperature operation is enabled by choice of a special device material, namely silicon carbide (SiC), and a special switch structure, namely Nano-Electro-Mechanical-System (NEMS) switch. While SiC provides excellent mechanical and chemical properties suitable for operation at extreme harsh environment, NEMS switch provides low-voltage operation, ultra-low leakage and radiation hardness. We propose a novel multi-layer NEMS switch structure and efficient design of each building block of FPGA using nanoscale SiC NEMS switches. Using measured switch parameters from a number of SiC NEMS switches we fabricated, we compare the power, performance and area of an all-mechanical FPGA with alternative implementations for several benchmark circuits.

Various design-for-security (DFS) approaches have been proposed earlier for detection of hardware Trojans, which are malicious insertions in Integrated Circuits (ICs). In this paper, we highlight our major findings in terms of innovative Trojan design that can easily evade existing Trojan detection approaches based on functional testing or side-channel analysis. In particular, we illustrate design and placement of sequential hardware Trojans, which are rarely activated/observed and incur ultralow delay/power overhead. We provide models, examples, theoretical analysis of effectiveness, and simulation as well as measurement results of impact of these Trojans in a hardened design. It is shown that efficient design and placement of sequential Trojan would incur extremely low side-channel (power, delay) signature and hence, can easily evade both post-silicon validation and DFS (e.g. ring oscillator based) approaches.