IACR News item: 30 June 2015
Nicolas Méloni, M. Anwar Hasan
ePrint Report
Modular exponentiation is core to today\'s main stream
public key cryptographic systems. In this article, we generalize the
classical fractional $w$NAF method for modular exponentiation -- the
classical method uses a digit set of the form $\\{1,3,\\dots,m\\}$
which is extended here to any set of odd integers of the form
$\\{1,d_2,\\dots, d_n\\}$. We give a formula for the average density of
non-zero terms in this new representation and discuss its asymptotic
behavior when those digits are randomly chosen from a given set. We
also propose a specific method for the precomputation phase of the
exponentiation algorithm.
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