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\title{Long-Term Trust and Analog Computers}
\author{Andrew Poelstra}
\institute{\texttt{schnorr@wpsoftware.net}}
\date{May 5, 2022}

\usepackage{amsfonts,amsmath,latexsym,color,epsfig,graphicx}
\usepackage{graphicx}

\begin{document}

\setbeamertemplate{background} 
{
    %% This image CC4.0-BY by Michaela Paez
    \includegraphics[width=\paperwidth,height=\paperheight]{title-bg.png}
}

\frame{ \frametitle{}
\begin{center}
{\small MIT Bitcoin Expo, May 5, 2020}~\\~\\~\\
{\color{darkred}
\Huge
LONG TERM TRUST\\
\large ~\\ AND\\~\\
\Huge
ANALOG COMPUTERS}\\~\\~\\
Andrew Poelstra\\
{\tiny Director, Blockstream Research}\\
\end{center} }

\setbeamertemplate{background}  {}

%% Outline - 25 mins, early morning, MIT
%
% Backdoors and Bugs
%   - TI-85 predates me
% Spending Conditions: Scripts and Keys
% Key Tricks: Thresholds and Adaptors and Hidden Commitments
% Taproot Assumption
% Taproot: p2c + MAST
%
% Part 2: Designing for Bitcoin
% Is Bitcoin Dead?
% The weight of protocol changes
% Tradeoffs suck (no wasted bytes)
% Political things
% A Brief comment about segwit deployment
%

%%%% Begin part one
\frame
{
  \begin{center}
  \huge\color{brown}\underline{one}\\
  \Huge\color{darkred}
  Hardware Wallets
  \end{center}
}

\frame
{
  \frametitle{Digital Hardware}
  What makes a safe hardware wallet?\\~\\
  \begin{itemize}
  \item ``not your keys, not your coins''; own the hardware\\~\\
  \item trustworthy manufacturer\\~\\
  \item the ``genuine product'' seal is unbroken
  \end{itemize}
}

\frame
{
  \frametitle{Digital Hardware}
  What makes a safe hardware wallet?\\~\\
  \begin{itemize}
  \item secure element\\~\\
  \item Bitcoin focused; supports PSBT, Taproot, etc\\~\\
  \item simplicity? transparency?
  \end{itemize}
}

\frame
{
  \frametitle{Digital Hardware}
  What makes a safe hardware wallet?\\~\\
  \begin{itemize}
  \item air-gapped\\~\\
  \item pre-dates Bitcoin\\~\\
  \item looks like a keyboard? printer? TI-85? gameboy?
  \end{itemize}
}

\frame
{
  \frametitle{Digital Hardware}
  What makes a safe hardware wallet?\\~\\
  \begin{itemize}
  \item made out of paper and metal\\~\\
  \item pre-dates the Reformation\\~\\
  \item intermediate computations are literally incinerated
  \end{itemize}
}

\frame
{
  \begin{center}
  \huge\color{brown}\underline{two}\\
  \Huge\color{darkred}
  Trust and the Future
  \end{center}
}

\frame
{
  \frametitle{Failure Modes}
  How can you protect yourself?\\~\\
  \begin{itemize}
  \item installing every software update?\\~\\
  \item never installing software updates?\\~\\
  \item updating hardware? stockpiling old hardware?\\~\\
  \item never testing your backups? frequently testing your backups?
  \end{itemize}
}

\frame
{
  \begin{center}
  \huge\color{brown}\underline{three}\\
  \Huge\color{darkred}
  Trust and the Present
  \end{center}
}

\frame
{
  \frametitle{Failure Modes}
  How can a hardware wallet fail?\\~\\
  \begin{itemize}
  \item generating bad keys\\~\\
  \item signing without a PIN/button press\\~\\
  \item directly leaking key material
  \end{itemize}
}

\frame
{
  \frametitle{Failure Modes}
  How can a hardware wallet fail?\\~\\
  \begin{itemize}
  \item storage that won't erase\\~\\
  \item signing things it shouldn't\\~\\
  \item leaking key material via sidechannels
  \end{itemize}
}

\frame
{
  \begin{center}
  \huge\color{brown}\underline{four}\\
  \Huge\color{darkred}
  Volvelles (Trust the Past)
  \end{center}
}

\frame
{
  \frametitle{Volvelles}
  A \textbf{volvelle} is a paper computer made from two rotating discs\\~\\
  \begin{itemize}
  \item Persia, 11th century (according to Wikipedia)\\~\\
  \item used for early symmetric crypto (Alberti, 15th century)\\~\\
  \item can implement finite field arithmetic (Galois, 19th century)\\~\\
  \item such as polynomial interpolation (Lagrange, 18th century)\\~\\
  \item this is Shamir's Secret Sharing! (Shamir, 20th century)
  \end{itemize}
}

\frame
{
  \frametitle{Volvelles}
  \begin{center}\includegraphics[scale=0.15]{color-volvelle.jpg}\end{center}
}

\frame
{
  \frametitle{Volvelles}
  \begin{center}\includegraphics[scale=0.145]{wood-full.jpg}\end{center}
}

\frame
{
  \frametitle{Volvelles}
\begin{quote}
And in those days there appeared in Alexandria a female philosopher, a pagan named Hypatia, and she was devoted at all times to magic, astrolabes and instruments of music, and she beguiled many people through (her) Satanic wiles.
\end{quote}

~\\
\raggedleft
-- John, Bishop of Nikiu, from his \emph{Chronicle} 84.87-103,\\
writing some 300 years later% ,\\
%having obtained zero of Hypatia's bitcoins)
}


\frame
{
  \frametitle{Volvelles}
  \textbf{codex32} is a volvelle-based scheme that can\\~\\
  \begin{itemize}
  \item generate random data (via de-biased dice)\\~\\
  \item compute and verify checksums\\~\\
  \item split and reconstruct secrets\\~\\
  \item do symmetric encryption (via 2-of-2 secret sharing)
  \end{itemize}
}

\frame
{
  \frametitle{Volvelles}
  \includegraphics[scale=0.25]{dice-game.jpg}
}

\frame
{
  \frametitle{Volvelles}
  \begin{center}\includegraphics[scale=0.6]{volvelle-1.jpg}\end{center}
}

\frame
{
  \frametitle{Volvelles}
  \begin{center}\includegraphics[scale=0.1]{volvelle-2.jpg}\end{center}
}

\frame
{
  \frametitle{Volvelles}
  \begin{center}\includegraphics[scale=0.3]{volvelle-2.jpg}\end{center}
}

\frame
{
  \frametitle{Volvelles}
  Benefits of paper:\\~\\
  \begin{itemize}
  \item no EMF, microscopic storage, sidechannels\\~\\
  \item understandable and verifiable without tools\\~\\
  \item will continue to work, no matter how tech changes\\~\\
  \end{itemize}
}

\frame
{
    \frametitle{~}
    \begin{center}
    {\Large
    \texttt{github.com/roconnor-blockstream/SSS32}\\~\\~\\
}
    Volvelles by Leon Olsson Curr and Pearlwort Snead\\
    Artwork by Michaela Paez (CC-BY)\\~\\
    \texttt{pearlwort@wpsoftware.net}\\~\\~\\
% FIXME Blockstream REsearch
    \includegraphics[scale=0.5]{blockstream.png}
    \end{center}
}

\end{document}