\begin{frame}
	\begin{columns}
		\begin{column}{0.5\textwidth}
			\mktitle{Outline}
			\begin{enumerate}
				\item Setting and problem
				\item Design overview
				\item How to get involved
			\end{enumerate}
		\end{column}
		\begin{column}{0.5\textwidth}
			\centering
			\includegraphics[width=\columnwidth]{img/rgdd}
			\burl{https://creativecommons.org/licenses/by-sa/4.0/}
		\end{column}
	\end{columns}
\end{frame}

\begin{frame}
	%
	% 1. Introduce the system.  Think first two paragraphs in design.md
	%
	\mktitle{Our starting point}
	\begin{columns}
		\begin{column}{0.5\textwidth}
			\begin{itemize}
				\item Data publisher
				\item End-user
				\item Assumptions
					\begin{itemize}
						\item Public key can be located
						\item Signed data can be located
						\item End-user can install extra tooling
					\end{itemize}
			\end{itemize}
		\end{column}
		\begin{column}{0.5\textwidth}
			\centering
			\input{img/before}
		\end{column}
	\end{columns}
	\vfill
	\pause
	\alert{The attacker can compromise the data publisher}\\
	\pause
	\alert{The goal is to detect unwanted key-usage}
\end{frame}

\begin{frame}
	%
	% 1. Our design is about transparency logs.  So, I need to explain briefly
	% what a transparency log is.
	% 2. Append-only Merkle tree.  You can think of the data as being stored in
	% the leaves.  Each leaf is hashed.  Parents concatenate their children
	% hashes to produces their own hash values.  Repeat until single root hash.
	% 3. The root hash is usually called a tree head.
	% 4. Tree head interesting because it fixes the structure and the content of
	% the tree.  Add/remove/modify -> new tree head.
	% 5. If the log signs the tree head, you can hold it accountable for its
	% structure and content.
	% 6. This is important because the attacker can control the log.
	% 7. So we cannot trust that the log is append-only.  We will need to verify
	% that.  To this end we have consistency proofs.  The intuition is that you
	% can force the log to reveal a number of cryptographic hashes.  These
	% hashes will prove that the tree head you see today is consistent with the
	% tree head you saw yesterday.
	% 8. You can also prove that something is in the log efficiently.  This is
	% called an inclusion proof.  The intuition is that you reveal a number of
	% hashes.  If you can use them to reconstruct the root of a globally
	% consistent tree head you can be sure that some data is in the log.
	% 8. Global consistency (as opposed to just consistency) is what prevents
	% the log from creating forks.  I will return to this later on because it is
	% an important part of our design.
	% (9. Not having global consistency would be like having a blockchain
	% without a consensus mechanism.)
	%
	\mktitle{A quick step back---Transparency log crash course}
	\input{img/mt}
	\vfill
	\begin{columns}
		\begin{column}{0.33\textwidth}
			\begin{itemize}
				\item Tree head
			\end{itemize}
		\end{column}
		\begin{column}{0.33\textwidth}
			\begin{itemize}
				\item Consistency proof
			\end{itemize}
		\end{column}
		\begin{column}{0.33\textwidth}
			\begin{itemize}
				\item Inclusion proof
			\end{itemize}
		\end{column}
	\end{columns}
	\vfill
	\pause
	\alert{The attacker can control the log}
\end{frame}

\begin{frame}
	\mktitle{Preparing a logging request}
	\begin{columns}
		\begin{column}{0.5\textwidth}
			\begin{itemize}
				\item Select a shard hint and checksum
				\item Sign using your private key
			\end{itemize}
		\end{column}
		\begin{column}{0.5\textwidth}
			\lstinputlisting[style=CStyle]{img/tree-leaf.trunnel}
		\end{column}
	\end{columns}
\end{frame}

\begin{frame}
	\mktitle{Submitting a logging request}
	\begin{columns}
		\begin{column}{0.2\textwidth}
			\underline{Key-value pairs:}
			\begin{itemize}
				\item Shard hint
				\item Checksum
				\item Signature
				\item Public key
				\item Domain hint
			\end{itemize}
		\end{column}
		\begin{column}{0.8\textwidth}
			\centering
			\input{img/log-request}
		\end{column}
	\end{columns}
\end{frame}

\begin{frame}
	\mktitle{Distributing proofs of public logging}
	\begin{columns}
		\begin{column}{0.5\textwidth}
			\begin{itemize}
				\item End-user will not talk to the log
				\item Proofs of logging
					\begin{itemize}
						\item Inclusion proof
						\item Tree head
					\end{itemize}
				\item Witness cosigning
			\end{itemize}
		\end{column}
		\begin{column}{0.5\textwidth}
			\centering
			\input{img/after}
		\end{column}
	\end{columns}
	\pause
	\alert{The attacker can control a threshold of witnesses}
\end{frame}

\begin{frame}
	\mktitle{Summary and additional details}
	\begin{columns}
		\begin{column}{0.5\textwidth}
			\begin{itemize}
				\item Signed checksums
				\item Sharding
				\item Preserved data flows
				\item Anti-spam
				\item Global consistency
				\item Few simple parsers
				\item No cryptographic agility
			\end{itemize}
		\end{column}
		\begin{column}{0.5\textwidth}
			\includegraphics[width=\columnwidth]{img/clean}
		\end{column}
	\end{columns}
\end{frame}

\begin{frame}
	\vfill
	\begin{columns}
		\begin{column}{0.7\textwidth}
			\mktitle{Get involved}
			\begin{itemize}
				\item Feedback on our v0 design\footnotemark and API\footnotemark?
				\item Is this a service that you would use?  Why (not)?
				\item Want to run an experimental log or witness?
				\item Implementation and tooling is still early-days
				\item Reach out via slack\footnotemark, IRC\footnotemark, GitHub, or DM
			\end{itemize}
		\end{column}
		\begin{column}{0.3\textwidth}
			\centering
			\includegraphics[width=\columnwidth]{img/thanks}
		\end{column}
	\end{columns}
	\footnotetext[1]{\burl{https://github.com/system-transparency/stfe/blob/design/doc/design.md}}
	\footnotetext[2]{\burl{https://github.com/system-transparency/stfe/blob/design/doc/api.md}}
	\footnotetext[3]{\burl{https://communityinviter.com/apps/system-transparency/join}}
	\footnotetext[4]{\tiny{\texttt{irc/oftc \#siglog}}}
\end{frame}