X-Git-Url: https://bilbo.iut-bm.univ-fcomte.fr/and/gitweb/16dcc.git/blobdiff_plain/d68de43fbfbc44e3363780b39401bf1d2683f9d8..6c611637ef05c993351fece7ff89ee10a2090031:/generating.tex diff --git a/generating.tex b/generating.tex index 354058a..d512a98 100644 --- a/generating.tex +++ b/generating.tex @@ -7,12 +7,11 @@ if and only if its Markov matrix is a doubly stochastic matrix. In~\cite[Section 4]{DBLP:conf/secrypt/CouchotHGWB14}, -we have presented an efficient -approach which generates +we have presented a general scheme which generates function with strongly connected iteration graph $\Gamma(f)$ and with doubly stochastic Markov probability matrix. -Basically, let consider the ${\mathsf{N}}$-cube. Let us next +Basically, let us consider the ${\mathsf{N}}$-cube. Let us next remove one Hamiltonian cycle in this one. When an edge $(x,y)$ is removed, an edge $(x,x)$ is added. @@ -46,10 +45,10 @@ cycle is removed, is doubly stochastic. Let us consider now a ${\mathsf{N}}$-cube where an Hamiltonian cycle is removed. Let $f$ be the corresponding function. -The question which remains to solve is -can we always find $b$ such that $\Gamma_{\{b\}}(f)$ is strongly connected. +The question which remains to solve is: +\emph{can we always find $b$ such that $\Gamma_{\{b\}}(f)$ is strongly connected?} -The answer is indeed positive. We furtheremore have the following strongest +The answer is indeed positive. We furthermore have the following strongest result. \begin{thrm} There exist $b \in \Nats$ such that $\Gamma_{\{b\}}(f)$ is complete. @@ -59,9 +58,28 @@ There is an arc $(x,y)$ in the graph $\Gamma_{\{b\}}(f)$ if and only if $M^b_{xy}$ is positive where $M$ is the Markov matrix of $\Gamma(f)$. It has been shown in~\cite[Lemma 3]{bcgr11:ip} that $M$ is regular. -There exists thus $b$ such there is an arc between any $x$ and $y$. +Thus, there exists $b$ such that there is an arc between any $x$ and $y$. \end{proof} -The next section presents how to build hamiltonian cycles in the +This section ends with the idea of removing a Hamiltonian cycle in the +$\mathsf{N}$-cube. +In such a context, the Hamiltonian cycle is equivalent to a Gray code. +Many approaches have been proposed a way to build such codes, for instance +the Reflected Binary Code. In this one, one of the bits is switched +exactly $2^{\mathsf{N}-}$ \ANNOT{formule incomplète : $2^{\mathsf{N}-1}$ ??} for a $\mathsf{N}$-length cycle. + +%%%%%%%%%%%%%%%%%%%%% + +The function that is built +from the \ANNOT{Phrase non terminée} + +The next section presents how to build balanced Hamiltonian cycles in the $\mathsf{N}$-cube with the objective to embed them into the pseudorandom number generator. + +%%% Local Variables: +%%% mode: latex +%%% TeX-master: "main" +%%% ispell-dictionary: "american" +%%% mode: flyspell +%%% End: