1 \section{Lyapunov exponent evaluation of a digital watermarking scheme proven to be secure~\cite{bfg12:ip}}
3 In this short paper, we have computed the Lyapunov exponent of the one bit
4 watermarking scheme published in~\cite{gfb10:ip} (see Section~\ref{sec:iihmsp10}),
5 to improve our knowledge of its topological security.
6 To evaluate this Lyapunov exponent,
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7 chaotic iterations must be described by a differentiable function on $\mathds{R}$.
9 a topological semiconjugacy between the phase space $\mathcal{X}$ and
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10 $\mathds{R}$ must be written.
11 As this article is simply a rewriting in the digital watermarking field
12 of an unpublished result on chaotic iterations obtained during our
13 thesis, we will not say any more about this publication.
