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+\section{Pull payment (aka invoicing)}
+
+\begin{figure}[h!]
+  \begin{sequencediagram}
+    \newinst{payer}{\shortstack{Payer \\
+      \\ \begin{tikzpicture}
+        \node [fill=gray!20,draw=black,thick,align=center] {Pre-funded \\ Wallet};
+      \end{tikzpicture}
+    }}
+    \newinst[2]{exchange}{\shortstack{Taler (exchange) \\
+       \\ \begin{tikzpicture}[shape aspect=.5]
+        \tikzset{every node/.style={cylinder,shape border rotate=90, draw,fill=gray!25}}
+        \node at (1.5,0) {\shortstack{{{\tiny Database}}}};
+       \end{tikzpicture}
+    }}
+    \newinst[2]{payee}{\shortstack{Payee \\
+      \\ \begin{tikzpicture}
+        \node [fill=gray!20,draw=black,thick,align=center] { Unique \\ Wallet ID};
+      \end{tikzpicture}
+    }}
+    \postlevel
+    \begin{callself}{payee}{Review pull payment fees}{}
+    \end{callself}
+    \mess[0]{payee}{{Create invoice (Wallet ID)}}{exchange}
+
+    \mess[0]{exchange}{{Invoice ready}}{payee}
+    \mess[0]{payee}{{Send invoice (e.g. via QR code)}}{payer}
+
+    \begin{callself}{payer}{Review invoice}{}
+    \end{callself}
+    \mess[0]{payer}{{Make payment (Coins)}}{exchange}
+
+    \begin{sdblock}{Domestic wallet?}{}
+    \begin{callself}{exchange}{Figure~\ref{fig:proc:domestic}}{}
+    \end{callself}
+    \end{sdblock}
+    \begin{sdblock}{KYC/AML required?}{}
+    \begin{callself}{exchange}{Figures~\ref{fig:proc:kyc}, \ref{fig:proc:aml}}{}
+    \end{callself}
+    \end{sdblock}
+
+    \mess[0]{exchange}{{Distribute digital cash}}{payee}
+
+\end{sequencediagram}
+  \caption{Interactions between wallets and Taler exchange
+    in a pull payment.}
+  \label{fig:int:pull}
+\end{figure}
+
+We do {\bf not} permit the payer to regain control over their funds, once the
+payment was made they are locked {\em until} the payee passes the KYC/AML
+checks.  We only do the AML/KYC process once the funds are locked at the
+exchange. This ensures we know the actual transacted amounts (which may be
+lower than the total amounts requested) and prevents risk-free probing
+attacks.