diff --git a/docs/presentations/autre/WinterSchoolGDRCyber2026/convergence_hc.tex b/docs/presentations/autre/WinterSchoolGDRCyber2026/convergence_hc.tex
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+++ b/docs/presentations/autre/WinterSchoolGDRCyber2026/convergence_hc.tex
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+\resizebox{\columnwidth}{!}{
+ \begin{tikzpicture}[
+ roundnode/.style={circle, draw=black, fill=black, very thick, minimum size=1pt,},
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diff --git a/docs/presentations/autre/WinterSchoolGDRCyber2026/images/logo_AMU.svg b/docs/presentations/autre/WinterSchoolGDRCyber2026/images/logo_AMU.svg
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diff --git a/docs/presentations/autre/WinterSchoolGDRCyber2026/localiteetat_hc.tex b/docs/presentations/autre/WinterSchoolGDRCyber2026/localiteetat_hc.tex
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+\resizebox{\columnwidth}{!}{%
+ \begin{tikzpicture}[
+ roundnode/.style={circle, draw=black, fill=black, very thick, minimum size=1pt,},
+ ignorednode/.style={circle, draw=black!20, fill=black!20, very thick, minimum size=1pt,},
+ arrow/.style={|->, thick,},
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+ ]
+
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+ \node[left] at (11.west) {$p_0$};
+ \node[above] at (11.north) {$w(1)$};
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diff --git a/docs/presentations/autre/WinterSchoolGDRCyber2026/main.tex b/docs/presentations/autre/WinterSchoolGDRCyber2026/main.tex
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+\documentclass{beamer}
+\usetheme{Boadilla}
+\usecolortheme{orchid}
+
+\usepackage[T1]{fontenc}
+\usepackage[utf8]{inputenc}
+\usepackage[french]{babel}
+\usepackage{stackengine}
+
+\addtobeamertemplate{navigation symbols}{}{%
+ \usebeamerfont{footline}%
+ \usebeamercolor[fg]{footline}%
+ \hspace{1em}%
+ \insertframenumber/\inserttotalframenumber
+}
+\usepackage{ulem}
+\usepackage{tkz-tab}
+\setbeamertemplate{blocks}[rounded]%
+[shadow=true]
+\AtBeginSection{%
+ \begin{frame}
+ \tableofcontents[sections=\value{section}]
+ \end{frame}
+}
+
+\usepackage{tikz}
+\usetikzlibrary{positioning}
+\usetikzlibrary{calc}
+\usetikzlibrary{arrows.meta}
+
+\title{Amaury JOLY - Winter School GDR Cybersécurité}
+\author{Amaury JOLY}
+\institute{Université Aix-Marseille \\ Laboratoire d'Informatique et Systèmes (LIS)}
+\date{Janvier 2026}
+
+\begin{document}
+
+\begin{frame}
+ \titlepage
+ \vspace{-1.2em}
+
+ \begin{center}
+ \includegraphics[height=1cm]{images/logoamu}\hspace{1cm}%
+ \includegraphics[height=1.5cm]{images/logolis}\hspace{1cm}
+ \includegraphics[height=0.9cm]{images/logodalgo}\hspace{1cm}%
+ \includegraphics[height=0.6cm]{images/logoparsec}
+ \end{center}
+\end{frame}
+
+
+\begin{frame}{Who am I?}
+ \begin{itemize}
+ \item \textbf{Amaury JOLY}
+ \item 3rd-year PhD candidate at the \textbf{Laboratory of Informatics and Systems (LIS)}
+ \item \textbf{Distributed Algorithms} team
+ \item Supervised by \textbf{Emmanuel GODARD} and \textbf{Corentin TRAVERS}
+ \item \textbf{CIFRE} PhD with the company \textbf{Parsec}
+ \end{itemize}
+\end{frame}
+
+%------------------------------------------------------------
+\begin{frame}{Parsec: company \& product}
+ \begin{itemize}
+ \item \textbf{Parsec} develops an end-to-end encrypted file sharing platform
+ \item Client--server solution: users collaborate through shared workspaces
+ \item \textbf{End-to-end encryption}: the server only sees \emph{ciphertexts}
+ \item \textbf{Distributed PKI management among clients} (keys/identities handled at the edge)
+ \item \alert{one central server stores encrypted data and redistributes it to clients}
+ \end{itemize}
+\end{frame}
+
+%------------------------------------------------------------
+\begin{frame}{My topic (high level)}
+ \begin{block}{Problem statement}
+ \textit{``Weak consistency in a zero-trust cloud for real-time collaborative applications.''}
+ \end{block}
+
+ \vspace{0.4em}
+ \begin{itemize}
+ \item Real-time collaboration: concurrent updates, low latency, intermittent connectivity
+ \item We want \textbf{weak consistency} (e.g., eventual / causal behaviors) with clear semantics under concurrency
+ \item \textbf{Zero-trust cloud} (Parsec-like setting):
+ \begin{itemize}
+ \item central server trusted for \textbf{availability} only
+ \item server can be \textbf{honest-but-curious} (observes metadata, stores/forwards ciphertexts)
+ \item \textbf{no trust assumptions on clients} (they may be compromised or mutually distrustful)
+ \end{itemize}
+ \end{itemize}
+\end{frame}
+
+\begin{frame}
+ \frametitle{Our Model}
+ \begin{block}{Assumptions}
+ \begin{itemize}
+ \item The system is highly connected
+ \item The system is not partitionable
+ \item The system is asynchronous (i.e., no assumption on message delays or relative process speeds)
+ \item Nodes can fail by \textbf{crash} (i.e., stop functioning)
+ \item Nodes can be \textbf{Byzantine} (i.e., arbitrary behavior)
+ \item The communication network is reliable but byzantine nodes can delay or reorder messages
+ \item There is a Reliable Broadcast abstraction available
+ \end{itemize}
+ \end{block}
+\end{frame}
+
+\begin{frame}
+ \frametitle{Consistency classes}
+ \begin{columns}
+ \column{0.5\textwidth}
+ \resizebox{\columnwidth}{!}{
+ \includegraphics{images/carte_criteres.png}
+ }
+
+ \column{0.5\textwidth}
+ One approach to define the consistency of an algorithm is to place the concurrent history it produces into a consistency class. \\
+ We can define 3 consistency classes:
+ \begin{itemize}
+ \item \textbf{State Locality} (LS)
+ \item \textbf{Validity} (V)
+ \item \textbf{Eventual Consistency} (EC)
+ \end{itemize}
+ \end{columns}
+\end{frame}
+
+\begin{frame}
+ \frametitle{State Locality (LS)}
+
+ \begin{columns}
+ \column{0.4\textwidth}
+ \include{localiteetat_hc}
+ \column{0.6\textwidth}
+ \begin{block}{Definition}
+ For every process $p$, there exists a linearization containing all of $p$'s read operations. \\
+ \end{block}
+ \begin{math}
+ \begin{array}{ll}
+ e.g.: & \textcolor{blue}{C_{p_1} = \{r/(0,0), r/(0,2)^w, w(2)\}}, \\
+ & \textcolor{red}{C_{p_2} = \{r/(0,0), r/(0,1)^w, w(1)\}}, \\
+ & \textcolor{blue}{r/(0,0) \bullet w(2) \bullet r/(0,2)^w} \\
+ & \textcolor{red}{r/(0,0) \bullet w(1) \bullet r/(0,1)^w} \\
+ \end{array}
+ \end{math}
+ \end{columns}
+
+
+ \begin{flushright}
+ \begin{math}
+ LS = \left\{
+ \begin{array}{l}
+ \mathcal{T} \rightarrow \mathcal{P}(\mathcal{H}) \\
+ T \rightarrow \left\{
+ \begin{tabular}{lll}
+ $H \in \mathcal{H}:$ & \multicolumn{2}{l}{$\forall p \in \mathcal{P}_H, \exists C_p \subset E_H,$} \\
+ & & $\hat{Q}_{T,H} \subset C_p$ \\
+ & $\land$ & $lin(H[p \cap C_p / C_p]) \cap L(T) \neq \emptyset$ \\
+ \end{tabular}
+ \right. \\
+ \end{array}
+ \right.
+ \end{math}
+ \end{flushright}
+\end{frame}
+
+
+\begin{frame}
+ \frametitle{Validity (V)}
+
+ \begin{columns}
+ \column{0.4\textwidth}
+ \include{validite_hc}
+ \column{0.6\textwidth}
+ \begin{block}{Definition}
+ There exists a co-finite set of events such that for each of them, a linearization of all write operations justifies them. \\
+ \end{block}
+ \begin{math}
+ \begin{array}{ll}
+ e.g.: & E' = \{r/(2,1)^w, r/(1,2)^w\} \\
+ & w(2) \bullet w(1) \bullet \textcolor{red}{r/(2,1)^w} \\
+ & w(1) \bullet w(2) \bullet \textcolor{red}{r/(1,2)^w} \\
+ \end{array}
+ \end{math}
+ \end{columns}
+
+
+ \begin{flushright}
+ \begin{math}
+ V = \left\{
+ \begin{array}{l}
+ \mathcal{T} \rightarrow \mathcal{P}(\mathcal{H}) \\
+ T \rightarrow \left\{
+ \begin{array}{lll}
+ H \in \mathcal{H}: & \multicolumn{2}{l}{|U_{T,H}| = \infty} \\
+ & \lor & \exists E' \subset E_H, (|E_H \setminus E'| < \infty \\
+ & & \land \forall e \in E', lin(H[E_H / {e}]) \cap L(T) \neq \emptyset) \\
+ \end{array}
+ \right. \\
+ \end{array}
+ \right.
+ \end{math}
+ \end{flushright}
+\end{frame}
+
+
+\begin{frame}
+ \frametitle{Eventual Consistency (EC)}
+
+ \begin{columns}
+ \column{0.4\textwidth}
+ \include{convergence_hc}%
+ \column{0.5\textwidth}
+ \begin{block}{Definition}
+ There exists a co-finite set of events such that for each of them, a single linearization justifies them. \\
+ \end{block}
+ \begin{math}
+ \begin{array}{ll}
+ e.g.: & E' = \{r/(1,2)^w, r/(1,2)^w\} \\
+ & w(1) \bullet w(2) \bullet \textcolor{red}{r/(1,2)^w} \\
+ \end{array}
+ \end{math}
+ \end{columns}
+
+
+ \begin{flushright}
+ \begin{math}
+ EC = \left\{
+ \begin{array}{l}
+ \mathcal{T} \rightarrow \mathcal{P}(\mathcal{H}) \\
+ T \rightarrow \left\{
+ \begin{array}{lll}
+ H \in \mathcal{H}: & \multicolumn{2}{l}{|U_{T,H}| = \infty} \\
+ & \lor & \exists E' \subset E_H, |E_H \setminus E'| < \infty \\
+ & & \land \displaystyle\bigcap_{e \in E'} \delta_T^{-1}(\lambda(e)) \neq \emptyset \\
+ \end{array}
+ \right. \\
+ \end{array}
+ \right.
+ \end{math}
+ \end{flushright}
+\end{frame}
+
+\begin{frame}{Main Work}
+ \begin{itemize}
+ \item We designed a distributed algorithm that use a \textbf{byzantine-tolerant eventually consistent register} in our model to achieve Agreement with $t < n/3$ Byzantine nodes.
+ \item I'm working on a framework using this algorithm to build collaborative applications for the context of a zero-trust cloud.
+ \end{itemize}
+\end{frame}
+
+\begin{frame}
+ \frametitle{Thank you for your attention!}
+ \vfill
+ \begin{center}
+ \includegraphics[height=1cm]{images/logoamu}\hspace{1cm}%
+ \vspace{1em}
+
+ \includegraphics[height=1.5cm]{images/logolis}\hspace{1cm}%
+ \vspace{1em}
+
+ \includegraphics[height=0.9cm]{images/logodalgo}\hspace{1cm}%
+ \vspace{1em}
+
+ \includegraphics[height=0.6cm]{images/logoparsec}
+ \end{center}
+\end{frame}
+
+\end{document}
\ No newline at end of file
diff --git a/docs/presentations/autre/WinterSchoolGDRCyber2026/validite_hc.tex b/docs/presentations/autre/WinterSchoolGDRCyber2026/validite_hc.tex
new file mode 100755
index 0000000..2d0b836
--- /dev/null
+++ b/docs/presentations/autre/WinterSchoolGDRCyber2026/validite_hc.tex
@@ -0,0 +1,31 @@
+\resizebox{\columnwidth}{!}{%
+ \begin{tikzpicture}[
+ roundnode/.style={circle, draw=black, fill=black, very thick, minimum size=1pt,},
+ ignorednode/.style={circle, draw=black!20, fill=black!20, very thick, minimum size=1pt,},
+ arrow/.style={|->, thick,},
+ message/.style={->, blue!50, dashed, -{Circle[length=4pt,]}},
+ ]
+
+ \node[roundnode] (11) {};
+ \node[left] at (11.west) {$p_0$};
+ \node[above] at (11.north) {$w(1)$};
+ \node[roundnode] (12) [right=of 11] {};
+ \node[above] at (12.north) {$r/(0,1)$};
+ \node[roundnode] (13) [right=of 12] {};
+ \node[above] at (13.north) {$r/(2,1)^w$};
+
+ \draw[arrow] (11) -- (12);
+ \draw[arrow] (12) -- (13);
+
+ \node[roundnode] (21) [below=of 11] {};
+ \node[left] at (21.west) {$p_1$};
+ \node[below] at (21.south) {$w(2)$};
+ \node[roundnode] (22) [right=of 21] {};
+ \node[below] at (22.south) {$r/(0,2)$};
+ \node[roundnode] (23) [right=of 22] {};
+ \node[below] at (23.south) {$r/(1,2)^w$};
+
+ \draw[arrow] (21) -- (22);
+ \draw[arrow] (22) -- (23);
+ \end{tikzpicture}
+}
\ No newline at end of file