RSA Power Analysis Obfuscation: A Dynamic FPGA Architecture

The modular exponentiation operation used in popular public key encryption schemes, such as RSA, has been the focus of many side channel analysis (SCA) attacks in recent years. Current SCA attack countermeasures are largely static. Given sufficient signal-to-noise ratio and a number of power traces, static countermeasures can be defeated, as they merely attempt to hide the power consumption of the system under attack. This research develops a dynamic countermeasure which constantly varies the timing and power consumption of each operation, making correlation between traces more difficult than for static countermeasures. By randomizing the radix of encoding for Booth multiplication and randomizing the window size in exponentiation, this research produces a SCA countermeasure capable of increasing RSA SCA attack protection

Efficient Implementation on Low-Cost SoC-FPGAs of TLSv1.2 Protocol with ECC_AES Support for Secure IoT Coordinators

Security management for IoT applications is a critical research field, especially when taking into account the performance variation over the very different IoT devices. In this paper, we present high-performance client/server coordinators on low-cost SoC-FPGA devices for secure IoT data collection. Security is ensured by using the Transport Layer Security (TLS) protocol based on the TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256 cipher suite. The hardware architecture of the proposed coordinators is based on SW/HW co-design, implementing within the hardware accelerator core Elliptic Curve Scalar Multiplication (ECSM), which is the core operation of Elliptic Curve Cryptosystems (ECC). Meanwhile, the control of the overall TLS scheme is performed in software by an ARM Cortex-A9 microprocessor. In fact, the implementation of the ECC accelerator core around an ARM microprocessor allows not only the improvement of ECSM execution but also the performance enhancement of the overall cryptosystem. The integration of the ARM processor enables to exploit the possibility of embedded Linux features for high system flexibility. As a result, the proposed ECC accelerator requires limited area, with only 3395 LUTs on the Zynq device used to perform high-speed, 233-bit ECSMs in 413 µs, with a 50 MHz clock. Moreover, the generation of a 384-bit TLS handshake secret key between client and server coordinators requires 67.5 ms on a low cost Zynq 7Z007S device

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

A New Cross-Layer FPGA-Based Security Scheme for Wireless Networks

This chapter presents a new cross-layer security scheme which deploys efficient coding techniques in the physical layer in an upper layer classical cryptographic protocol system. The rationale in designing the new scheme is to enhance security-throughput trade-off in wireless networks which is in contrast to existing schemes which either enhances security at the detriment of data throughput or vice versa. The new scheme is implemented using the residue number system (RNS), non-linear convolutional coding and subband coding at the physical layer and RSA cryptography at the upper layers. The RNS reduces the huge data obtained from RSA cryptography into small parallel data. To increase the security level, iterated wavelet-based subband coding splits the ciphertext into different levels of decomposition. At subsequent levels of decomposition, the ciphertext from the preceding level serves as data for encryption using convolutional codes. In addition, throughput is enhanced by transmitting small parallel data and the bit error correction capability of non-linear convolutional code. It is shown that, various passive and active attacks common to wireless networks could be circumvented. An FPGA implementation applied to CDMA could fit into a single Virtex-4 FPGA due to small parallel data sizes employed