% public domain. no rights reserved. see
% https://creativecommons.org/publicdomain/zero/1.0/

\section{problem}

\begin{frame}
  \frametitle{problem}
  \centering
  ``L'' folks are in trouble.
\end{frame}

\begin{frame}
  \frametitle{``L'' are in trouble}
  \centering
  data stored in FSP's\footnote{FSP: File Storage Provider} computers $\ne$ private
\end{frame}

\begin{frame}
  \frametitle{the last resort}
  \centering
  encrypt everything!
\end{frame}

\begin{frame}[fragile]
  \frametitle{encrypt everthing}
  {\tiny
  \begin{semiverbatim}
                        /^^^^^^^^^^^^\\
                        |            |                           +-----+
                        |  crypt0    |                           |     |
        secret.txt ---> |  pr0gr4m   | --> secret.txt.cipher --> | FSP |
                        |            |                           |     |
                        |____________|                           +-----+

     FSP: File Storage Provider (Dropbox, Google Drive, etc).
  \end{semiverbatim}
  }
\end{frame}


\begin{frame}
  \frametitle{not enough}
  \centering
  our adversaries are too powerful.
\end{frame}


\begin{frame}[fragile]
  \frametitle{what if}

  {\tiny
  \begin{semiverbatim}
                                                             +-----+
                                                             |     |
                                  secret.txt.shard0   ---->  | FSP |
                   +------------+   ^                        |  1  |
                   |  /     /   |   |                        +-----+
                   |  crypt0    |   |
   secret.txt ---> |  pr0gr4m   | --|
                   | /     /    |   |
                   +____________+   |                        +-----+
                                    v                        |     |
                                  secret.txt.shard1   ---->  | FSP |
                                                             |  2  |
                                                             +-----+
FSP: File Storage Provider (Dropbox, Google Drive, etc).
  \end{semiverbatim}
  }

\end{frame}

\begin{frame}
  \centering
  enter combox
\end{frame}