Accelerating exp-log based finite field multiplication
Abstract
Finite field multiplication is widely used for masking countermeasures
against side-channel attacks. The execution time of finite field multipli-
cation implementation is critical as it greatly impacts the overhead of the
countermeasure. In this context, the use of exp-log tables is popular for
the implementation of finite field multiplication. Yet, its performance is
affected by the need for particular code to handle the case where one of
the operands equals zero, as log is undefined for zero. As noticed by two
recent papers, the zero case can be managed without any extra code by
extending the exp table and setting log[0] to a large-enough value. The
multiplication of a and b then becomes as simple as: exp[log[a] + log[b]].
In this paper, we compare this approach with other implementations of
finite field multiplication and show that it provides a good trade-off be-
tween memory use and execution time.
Origin : Files produced by the author(s)
Licence : CC BY NC ND - Attribution - NonCommercial - NoDerivatives
Licence : CC BY NC ND - Attribution - NonCommercial - NoDerivatives