X-Git-Url: https://bilbo.iut-bm.univ-fcomte.fr/and/gitweb/16dcc.git/blobdiff_plain/c069ead2bda7032833d2d7f3d0851906ec4d22f0..8dfce25f59a57787b53e1ba55971a5c4f8d5993f:/conclusion.tex diff --git a/conclusion.tex b/conclusion.tex index 2705043..a656965 100644 --- a/conclusion.tex +++ b/conclusion.tex @@ -1,27 +1,41 @@ This work has assumed a Boolean map $f$ which is embedded into a discrete-time dynamical system $G_f$. This one is supposed to be iterated a fixed number -$p_1$ or $p_2$,\ldots, or $p_{\mathds{p}}$ of +$p_1$ or $p_2$,\ldots, or $p_{\mathds{p}}$ times before its output is considered. This work has first shown that iterations of $G_f$ are chaotic if and only if its iteration graph $\Gamma_{\mathcal{P}}(f)$ is strongly connected where $\mathcal{P}$ is $\{p_1, \ldots, p_{\mathds{p}}\}$. -Any PRNG, which iterates $G_f$ as above -satisfies in some cases the property of chaos. +It can be deduced that in such a situation a PRNG, which iterates $G_f$, +satisfies the property of chaos and can be used in simulating chaos +phenomena. We then have shown that a previously presented approach can be directly applied here to generate function $f$ with strongly connected $\Gamma_{\mathcal{P}}(f)$. The iterated map inside the generator is built by first removing from a -$\mathsf{N}$-cube an Hamiltonian path and next +$\mathsf{N}$-cube a balanced Hamiltonian cycle and next by adding a self loop to each vertex. -The PRNG can thus be seen as a random walk of length in $\mathsf{P}$ +The PRNG can thus be seen as a random walk of length in $\mathcal{P}$ into this new $\mathsf{N}$-cube. -We furthermore have exhibited a bound on the number of iterations -that is sufficient to obtain a uniform distribution of the output. +We have presented an efficient method to compute such a balanced Hamiltonian +cycle. This method is an algebraic solution of an undeterministic +approach~\cite{ZanSup04} and has a low complexity. +To the best of the authors knowledge, this is the first time a full +automatic method to provide chaotic PRNGs is given. +Practically speaking, this approach preserves the security properties of +the embedded PRNG, even if it remains quite cost expensive. + + +We furthermore have presented an upper bound on the number of iterations +that is sufficient to obtain an uniform distribution of the output. +Such an upper bound is quadratic on the number of bits to output. +Experiments have however shown that such a bound is in +$\mathsf{N}.\log(\mathsf{N})$ in practice. Finally, experiments through the NIST battery have shown that the statistical properties are almost established for -$\mathsf{N} = 4, 5, 6, 7, 8$. + $\mathsf{N} = 4, 5, 6, 7, 8$ and should be observed for any +positive integer $\mathsf{N}$. In future work, we intend to understand the link between statistical tests and the properties of chaos for