Energy-efficient software implementation of long integer modular arithmetic

This paper investigates performance and energy characteristics of software algorithms for long integer arithmetic. We analyze and compare the number of RISC-like processor instructions (e.g. single-precision multiplication, addition, load, and store instructions) required for the execution of different algorithms such as Schoolbook multiplication, Karatsuba and Comba multiplication, as well as Montgomery reduction. Our analysis shows that a combination of Karatsuba-Comba multiplication and Montgomery reduction (the so-called KCM method) allows to achieve better performance than other algorithms for modular multiplication. Furthermore, we present a simple model to compare the energy-efficiency of arithmetic algorithms. This model considers the clock cycles and average current consumption of the base instructions to estimate the overall amount of energy consumed during the execution of an algorithm. Our experiments, conducted on a StrongARM SA-1100 processor, indicate that a 1024-bit KCM multiplication consumes about 22% less energy than other modular multiplication techniques

Formal verification of a type flaw attack on a security protocol using object-z

We have identified a type flaw attack on the Amended Need-ham Schroeder Protocol with Conventional Keys due to a potential over-sight at the presentation layer of the network architecture. Using Object-Z, a formal specification of the protocol is presented allowing us to state the assumed properties of the presentation layer explicitly. Object-Z's schema calculus is used to verify the attack we have found and the weaknesses upon which the attack depends, thus enabling us to minimise the effort required to prevent the attack and to specify this as part of the model accordingly