The discrete logarithm is a problem that surfaces frequently in
the field of cryptography as a result of using the transformation
. Analysis
of the security of many cryptographic algorithms depends on the assumption that it is
statistically impossible to distinguish the use of this map from the use of a randomly
chosen map with similar characteristics. This paper focuses on a prime modulus,
,
for which it is shown that the basic structure of the functional graph
produced by this map is largely dependent on an interaction between
and
. We
deal with two of the possible structures, permutations and binary functional graphs.
Estimates exist for the shape of a random permutation, but similar estimates must
be created for the binary functional graphs. Experimental data suggest that both the
permutations and binary functional graphs correspond well to the theoretical
predictions.
Keywords
discrete logarithm problem, random map, functional graph