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\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}
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