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[GNUnet-SVN] [taler-marketing] branch master updated (ba8058b -> bf80020
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From: |
gnunet |
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Subject: |
[GNUnet-SVN] [taler-marketing] branch master updated (ba8058b -> bf80020) |
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Date: |
Sat, 05 Aug 2017 14:53:49 +0200 |
This is an automated email from the git hooks/post-receive script.
grothoff pushed a change to branch master
in repository marketing.
from ba8058b add Sandy
new bd2fd7f update presentation, merging in good parts of RMLL
new 281e55d Blockchain, Blockchain, Blockchain
new bf80020 modificatios for SHA
The 3 revisions listed above as "new" are entirely new to this
repository and will be described in separate emails. The revisions
listed as "add" were already present in the repository and have only
been added to this reference.
Summary of changes:
presentations/comprehensive/main.tex | 498 ++++++++++++++++------------
presentations/investors/investors2017ls.tex | 15 +
2 files changed, 308 insertions(+), 205 deletions(-)
diff --git a/presentations/comprehensive/main.tex
b/presentations/comprehensive/main.tex
index 2545254..98bc867 100644
--- a/presentations/comprehensive/main.tex
+++ b/presentations/comprehensive/main.tex
@@ -95,7 +95,7 @@
\usetikzlibrary{positioning}
\usetikzlibrary{calc}
-\title{Enabling Secure Web Payments with GNU Taler}
+\title{GNU Taler}
%\subtitle{}
\setbeamertemplate{navigation symbols}{\includegraphics[width=1cm]{inria.pdf}
\includegraphics[width=0.5cm]{gnu.png}
\includegraphics[width=0.5cm]{ashoka.png}\hfill}
@@ -109,23 +109,34 @@
\begin{document}
\justifying
-\begin{frame}[plain]
-\titlepage
-\vfill
-\begin{center}
-\tiny
-``I think one of the big things that we need to do, is we need
-to get a way from true-name payments on the Internet. The credit
-card payment system is one of the worst things that happened for the
-user, in terms of being able to divorce their access from their
-identity.'' \hfill --Edward Snowden, IETF 93 (2015)
-\end{center}
-\end{frame}
+\begin{frame}
+ \begin{center}
+ \LARGE {\bf GNU}
+ \vfill
+% \includegraphics[width=0.66\textwidth]{logo-2017-fr.pdf}
+ \includegraphics[width=0.66\textwidth]{../investors/taler-logo-2017.pdf}
+ \end{center}
+\begin{textblock*}{4cm}(.5cm,6.5cm) % {block width} (coords)
+ {\Large {\bf \url{taler.net}} \\
+ IRC{\bf \#taler} \\
+ {\small (on freenode)} \\
+ address@hidden \\
+ address@hidden }
+\end{textblock*}
+
+% Substitute based on who is giving the talk!
+ \begin{textblock*}{6cm}(6.7cm,7.7cm) % {block width} (coords)
+ {\hfill {\Large {\bf grothoff \&} \\
+ \hfill {\bf jeff} \& {\bf sereni-t}} \\
+ \hfill \{grothoff,jeff,address@hidden }
+\end{textblock*}
+
+\end{frame}
-\begin{frame}%[t]
+\begin{frame}{A Social Problem}
% \vfill
This was a question posed to RAND researchers in 1971:
@@ -138,10 +149,75 @@ identity.'' \hfill --Edward Snowden, IETF 93 (2015)
\begin{center}
\Large \textbf{Mastercard/Visa are too transparent.}
\end{center}
+\vfill
+ \begin{center}
+``I think one of the big things that we need to do, is we need
+to get a way from true-name payments on the Internet. The credit
+card payment system is one of the worst things that happened for the
+user, in terms of being able to divorce their access from their
+identity.'' \hfill --Edward Snowden, IETF 93 (2015)
+\end{center}
+
+\end{frame}
+
+
+
+\section{The Bank's Problem}
+\begin{frame}{The Bank's Problem}
+
+ 3D secure (``verified by visa'') is a nightmare:
+
+ \begin{minipage}{5cm}
+ \begin{itemize}
+ \item Complicated process
+ \item Shifts liability to consumer
+ \item Significant latency
+ \item Can refuse valid requests
+ \item Legal vendors excluded
+ \item No privacy for buyers
+ \end{itemize}
+ \end{minipage}
+ \begin{minipage}{5cm}
+ \includegraphics[width=\textwidth]{illustrations/cc3ds.pdf}
+ \end{minipage}
+ \vfill
+ Online credit card payments will be replaced, but with what?
+\end{frame}
+
+
+\begin{frame}{The Bank's Problem}
+\vfill
+ \begin{textblock*}{12cm}(0.5cm,1cm) % {block width} (coords)
+ \begin{itemize}
+ \item Global tech companies push oligopolies
+ \item Privacy and federated finance are at risk
+% \item 30\% fees are conceivable
+ \item Economic sovereingity is in danger
+ \end{itemize}
+\end{textblock*}
+\begin{textblock*}{4cm}(3.5cm,5.2cm) % {block width} (coords)
+ {\includegraphics[width=\textwidth]{../investors/competitor-logos/amazon.png}}
+\end{textblock*}
+\begin{textblock*}{2cm}(7cm,3cm) % {block width} (coords)
+
{\includegraphics[width=\textwidth]{../investors/competitor-logos/alipay.jpeg}}
+\end{textblock*}
+\begin{textblock*}{2cm}(3cm,3.5cm) % {block width} (coords)
+
{\includegraphics[width=\textwidth]{../investors/competitor-logos/paypal.jpeg}}
+\end{textblock*}
+\begin{textblock*}{2cm}(9cm,5cm) % {block width} (coords)
+
{\includegraphics[width=\textwidth]{../investors/competitor-logos/applepay.jpeg}}
+\end{textblock*}
+\begin{textblock*}{2cm}(7.5cm,5.9cm) % {block width} (coords)
+
{\includegraphics[width=\textwidth]{../investors/competitor-logos/samsungpay.jpeg}}
+\end{textblock*}
+\begin{textblock*}{1cm}(9.5cm,6.3cm) % {block width} (coords)
+
{\includegraphics[width=\textwidth]{../investors/competitor-logos/android_pay.png}}
+\end{textblock*}
+\vfill
\end{frame}
-\begin{frame}{Bitcoin}
+\begin{frame}{The Distraction: Bitcoin}
\begin{itemize}
\item Unregulated payment system and currency:
@@ -185,7 +261,11 @@ ZeroCoin, CryptoNote (Monero) and ZeroCash (ZCash) offer
anonymity.
\begin{frame}
\vfill
\begin{center}
-{\bf Is society ready for an anarchistic economy?}
+{\bf Do you want to have a libertarian economy?}
+\end{center}
+ \vfill
+\begin{center}
+{\bf Do you want to live under total surveillance?}
\end{center}
\vfill
\end{frame}
@@ -210,22 +290,48 @@ ZeroCoin, CryptoNote (Monero) and ZeroCash (ZCash) offer
anonymity.
\end{frame}
+\section{What is Taler?}
\begin{frame}{What is Taler?}
\vfill
\begin{center}
-Taler is an electronic payment system.
+Taler is an electronic instant payment system.
\end{center}
\begin{itemize}
- \item Pay in existing currencies (i.e. EUR, USD)
- \item Uses electronic coins stored in wallets on customer's device
+ \item Uses electronic coins stored in {\bf wallets} on customer's device
+ \item Like {\bf cash}
+ \item Pay in {\bf existing currencies} (i.e. EUR, USD, BTC), \\
+ or use it to create new {\bf regional currencies}
\end{itemize}
\vfill
\end{frame}
\begin{frame}
+\frametitle{Taler Overview}
+\begin{center}
+\begin{tikzpicture}
+ \tikzstyle{def} = [node distance= 5em and 6.5em, inner sep=1em, outer
sep=.3em];
+ \node (origin) at (0,0) {};
+ \node (exchange) [def,above=of origin,draw]{Exchange};
+ \node (customer) [def, draw, below left=of origin] {Customer};
+ \node (merchant) [def, draw, below right=of origin] {Merchant};
+% \node (auditor) [def, draw, above right=of origin]{Auditor};
+
+ \tikzstyle{C} = [color=black, line width=1pt]
+
+ \draw [<-, C] (customer) -- (exchange) node [midway, above, sloped]
(TextNode) {withdraw coins};
+ \draw [<-, C] (exchange) -- (merchant) node [midway, above, sloped]
(TextNode) {deposit coins};
+ \draw [<-, C] (merchant) -- (customer) node [midway, above, sloped]
(TextNode) {spend coins};
+% \draw [<-, C] (exchange) -- (auditor) node [midway, above, sloped]
(TextNode) {verify};
+
+\end{tikzpicture}
+\end{center}
+\end{frame}
+
+
+\begin{frame}
% TODO: replace with simplified NEW architecture picture!
-\frametitle{Architecture of GNU Taler}
+\frametitle{Architecture of Taler}
\begin{center}
\includegraphics[width=0.9\textwidth]{illustrations/taler-arch-full.pdf}
@@ -248,41 +354,65 @@ Taler is an electronic payment system.
\end{frame}
-\begin{frame}{Value proposition: Customer}
+\begin{frame}{Social Impact of Taler}
+ \begin{center}
+ \includegraphics[height=0.8\textheight]{../../social-impact.pdf}
+ \end{center}
+\end{frame}
+
+
+\begin{frame}{Use Case: Journalism}
+ Today:
+ \begin{itemize}
+ \item Corporate structure % ($\Rightarrow$ filter)
+ \item Advertising primary revenue % ($\Rightarrow$ dependence)
+ \item Tracking readers critical for business success
+ \item Journalism and marketing hard to distinguish
+ \end{itemize}\vfill\pause
+ With GNU Taler:
\begin{itemize}
- \item Convenient: pay with one click
- \item Guaranteed: never fear being rejected by false-positives in the fraud
detection
- \item Secure: like cash, except no worries about counterfeit
- \item Privacy-preserving: payment requires no personal information
- \item Stable: no currency fluctuations, pay in traditional currencies
- \item Free software: no hidden ``gadgets'', third parties can verify
+ \item One-click micropayments per article
+ \item Hosting requires no expertise % (no PCI DSS)
+ \item Reader-funded reporting separated from marketing
+ \item Readers can remain anonymous
\end{itemize}
\end{frame}
-\begin{frame}{Value proposition: Merchant}
+\begin{frame}{Use Cases: Refugee Camps}
+ Today:
+ \begin{itemize}
+ \item Non-bankable
+ \item Direct distribution of goods to population
+ \item Limited economic activity in camps
+ \item High level of economic dependence
+ \end{itemize}\vfill\pause
+ With GNU Taler:
\begin{itemize}
- \item Fast: transactions at Web-speed
- \item Secure: signed contracts, no legitimate customer rejected by fraud
decection
- \item Free software: competitive pricing and support
- \item Low fees: efficient protocol + no fraud $=$ low costs
- \item Flexible: any currency, any amount
- \item Ethical: no fluctuation risk, no pyramid scheme, not suitable for
illegal business
- \item Legal: complies with Regulation (EU) 2016/679 (GDPR)\footnote{Requires
privacy by design and data minimization for all data processing in Europe after
25.5.2018.}
+ \item Local currency issued as basic income backed by aid
+ \item Taxation possible based on economic status
+ \item Local governance enabled by local taxes
+ \item Increased economic independence and political participation
\end{itemize}
\end{frame}
-\begin{frame}{Value proposition: Government}
+\begin{frame}{Use Case: Anti-Spam}
+ Today, p$\equiv$p provides authenticated encryption for e-mail:
\begin{itemize}
- \item Libre $=$ commons: no monopoly, preserve independence
- \item Taxable: reduces black markets
- \item Efficient: high transaction costs hurt the economy
- \item Secure: signed contracts, no counterfeit
- \item Audited: no bad banks
- \item Private: protection against foreign espionage
+ \item Free software
+ \item Easy to use opportunistic encryption
+ \item Available for Outlook, Android, Enigmail
+ \item Spies \& spam filters can no longer inspect content
+ \end{itemize}\vfill\pause
+ With GNU Taler:
+ \begin{itemize}
+ \item Peer-to-peer payments via e-mail
+ \item If unsolicited sender, hide messages from user \&
+ automatically request payment from sender
+ \item Sender can attach payment to be moved to inbox
+ \item Receiver may grant refund to sender
\end{itemize}
- \hfill \includegraphics[width=4cm]{pics/blog_nsa_swift.jpg}
\end{frame}
@@ -301,50 +431,6 @@ Taler is an electronic payment system.
\end{frame}
-
-\begin{frame}{Merchant Integration: Wallet Detection}
- \lstset{language=JavaScript}
- \lstinputlisting{figs/taler-presence-js.html}
-% \caption{Sample code to detect the Taler wallet. Allowing the
-% Web site to detect the presence of the wallet leaks one bit
-% of information about the user. The above logic also works
-% if the wallet is installed while the page is open.}
-% \label{listing:presence}
-\end{frame}
-
-
-\begin{frame}{Merchant Integration: Payment Request}
-% \begin{figure}[p!]
- \lstset{language=HTML5}
- \lstinputlisting{figs/taler-402.html}
-% \caption{Sample HTTP response to prompt the wallet to show an offer.}
-% \label{listing:http-contract}
-% \end{figure}
-
-% \begin{figure*}[p!]
-% \lstset{language=HTML5}
-% \lstinputlisting{figs/taler-contract.html}
-% \caption{Sample JavaScript code to prompt the wallet to show an offer.
-% Here, the contract is fetched on-demand from the server.
-% The {\tt taler\_pay()} function needs to be invoked
-% when the user triggers the checkout.}
-% \label{listing:contract}
-% \end{figure*}
-\end{frame}
-
-
-\begin{frame}{Merchant Integration: Contract}
- % \begin{figure*}[t!]
- {\tiny
- \lstset{language=JavaScript}
- \lstinputlisting{figs/taler-contract.json}
-% \caption{Minimal Taler contract over a digital article with a value of
\EUR{0.10}. The merchant will pay transaction fees up to \EUR{0.01}. The hash
over the wire transfer information was truncated to make it fit to the page.}
-% \label{listing:json-contract}
- % \end{figure*}
- }
-\end{frame}
-
-
\begin{frame}{How does it work?}
We use a few ancient constructions:
\begin{itemize}
@@ -358,28 +444,6 @@ But of course we use modern instantiations.
\end{frame}
-\begin{frame}{Global setup: Pick an Elliptic curve}
-Need:
-\begin{description}
-\item[$G$]{generator in ECC curve, a point}
-\item[$o$]{size of ECC group, $o := |G|$, $o$ prime}
-\end{description}
-Now we can, for example, compute:
-\begin{align*}
- A &= G + G \\
- &= 2 G \\
- B &= A + G \\
- &= 3 G \\
- C &= c G \texttt { for } c \in {\mathbb Z}
-\end{align*}
-Note:
-\begin{align*}
-% 0 &= n G \\
- G &= (o + 1) G
-\end{align*}
-\end{frame}
-
-
\begin{frame}{Exchange setup: Create a denomination key (RSA)}
\begin{minipage}{6cm}
\begin{enumerate}
@@ -537,6 +601,7 @@ Note:
\end{center}
\end{frame}
+
\begin{frame}{Customer: Build shopping cart}
\begin{center}
\begin{tikzpicture}
@@ -552,6 +617,49 @@ Note:
\end{frame}
+\begin{frame}{Merchant Integration: Wallet Detection}
+ \lstset{language=JavaScript}
+ \lstinputlisting{figs/taler-presence-js.html}
+% \caption{Sample code to detect the Taler wallet. Allowing the
+% Web site to detect the presence of the wallet leaks one bit
+% of information about the user. The above logic also works
+% if the wallet is installed while the page is open.}
+% \label{listing:presence}
+\end{frame}
+
+
+\begin{frame}{Merchant Integration: Payment Request}
+% \begin{figure}[p!]
+ \lstset{language=HTML5}
+ \lstinputlisting{figs/taler-402.html}
+% \caption{Sample HTTP response to prompt the wallet to show an offer.}
+% \label{listing:http-contract}
+% \end{figure}
+
+% \begin{figure*}[p!]
+% \lstset{language=HTML5}
+% \lstinputlisting{figs/taler-contract.html}
+% \caption{Sample JavaScript code to prompt the wallet to show an offer.
+% Here, the contract is fetched on-demand from the server.
+% The {\tt taler\_pay()} function needs to be invoked
+% when the user triggers the checkout.}
+% \label{listing:contract}
+% \end{figure*}
+\end{frame}
+
+
+\begin{frame}{Merchant Integration: Contract}
+ % \begin{figure*}[t!]
+ {\tiny
+ \lstset{language=JavaScript}
+ \lstinputlisting{figs/taler-contract.json}
+% \caption{Minimal Taler contract over a digital article with a value of
\EUR{0.10}. The merchant will pay transaction fees up to \EUR{0.01}. The hash
over the wire transfer information was truncated to make it fit to the page.}
+% \label{listing:json-contract}
+ % \end{figure*}
+ }
+\end{frame}
+
+
\begin{frame}{Merchant: Propose contract (EdDSA)}
\begin{minipage}{6cm}
\begin{enumerate}
@@ -650,6 +758,30 @@ Note:
\end{frame}
+\begin{frame}{Diffie-Hellman (ECDH)}
+ \begin{minipage}{8cm}
+ \begin{enumerate}
+ \item Create private keys $d,h \mod o$
+ \item Define $D = dG$
+ \item Define $H = hG$
+ \item Compute $DH := d(hD) = h(dH)$
+ \end{enumerate}
+ \end{minipage}
+ \begin{minipage}{6cm}
+ \begin{tikzpicture}
+ \tikzstyle{def} = [node distance= 2em and 0.5em, inner sep=0em, outer
sep=.3em];
+ \node (h) [def, draw=none] at (0,0) {$h$};
+ \node (dh) [def, draw=none, below left=of
b]{\includegraphics[width=0.2\textwidth]{dh.pdf}};
+ \node (d) [def, draw=none, above left= of dh] {$d$};
+ \tikzstyle{C} = [color=black, line width=1pt]
+
+ \draw [<-, C] (dh) -- (d) node [midway, above, sloped] (TextNode) {};
+ \draw [<-, C] (dh) -- (h) node [midway, above, sloped] (TextNode) {};
+ \end{tikzpicture}
+ \end{minipage}
+\end{frame}
+
+
\begin{frame}{Strawman solution}
\begin{minipage}{8cm}
Given partially spent private coin key $c_{old}$:
@@ -690,30 +822,6 @@ Note:
\end{frame}
-\begin{frame}{Diffie-Hellman (ECDH)}
- \begin{minipage}{8cm}
- \begin{enumerate}
- \item Create private keys $d,h \mod o$
- \item Define $D = dG$
- \item Define $H = hG$
- \item Compute $DH := d(hD) = h(dH)$
- \end{enumerate}
- \end{minipage}
- \begin{minipage}{6cm}
- \begin{tikzpicture}
- \tikzstyle{def} = [node distance= 2em and 0.5em, inner sep=0em, outer
sep=.3em];
- \node (h) [def, draw=none] at (0,0) {$h$};
- \node (dh) [def, draw=none, below left=of
b]{\includegraphics[width=0.2\textwidth]{dh.pdf}};
- \node (d) [def, draw=none, above left= of dh] {$d$};
- \tikzstyle{C} = [color=black, line width=1pt]
-
- \draw [<-, C] (dh) -- (d) node [midway, above, sloped] (TextNode) {};
- \draw [<-, C] (dh) -- (h) node [midway, above, sloped] (TextNode) {};
- \end{tikzpicture}
- \end{minipage}
-\end{frame}
-
-
\begin{frame}{Customer: Transfer key setup (ECDH)}
\begin{minipage}{8cm}
Given partially spent private coin key $c_{old}$:
@@ -1021,6 +1129,7 @@ Note:
\item To give unlinkable change.
\item To give refunds to an anonymous customer.
\item To expire old keys and migrate coins to new ones.
+ \item To handle protocol aborts.
\end{itemize}
\noindent
\begin{center}
@@ -1031,45 +1140,6 @@ Note:
-\begin{frame}{Operational security}
- \begin{center}
- \resizebox{\textwidth}{!}{
-\begin{tikzpicture}[
- font=\sffamily,
- every matrix/.style={ampersand replacement=\&,column sep=2cm,row sep=2cm},
- source/.style={draw,thick,rounded corners,fill=green!20,inner sep=.3cm},
- process/.style={draw,thick,circle,fill=blue!20},
- sink/.style={source,fill=green!20},
- datastore/.style={draw,very thick,shape=datastore,inner sep=.3cm},
- dots/.style={gray,scale=2},
- to/.style={->,>=stealth',shorten
>=1pt,semithick,font=\sffamily\footnotesize},
- every node/.style={align=center}]
-
- % Position the nodes using a matrix layout
- \matrix{
- \node[source] (wallet) {Wallet};
- \& \node[process] (browser) {Browser};
- \& \node[process] (shop) {Web shop};
- \& \node[sink] (backend) {Taler backend}; \\
- };
-
- % Draw the arrows between the nodes and label them.
- \draw[to] (browser) to[bend right=50] node[midway,above] {(4) signed
contract}
- node[midway,below] {(signal)} (wallet);
- \draw[to] (wallet) to[bend right=50] node[midway,above] {(signal)}
- node[midway,below] {(5) signed coins} (browser);
- \draw[<->] (browser) -- node[midway,above] {(3,6) custom}
- node[midway,below] {(HTTPS)} (shop);
- \draw[to] (shop) to[bend right=50] node[midway,above] {(HTTPS)}
- node[midway,below] {(1) proposed contract / (7) signed coins} (backend);
- \draw[to] (backend) to[bend right=50] node[midway,above] {(2) signed
contract / (8) confirmation}
- node[midway,below] {(HTTPS)} (shop);
-\end{tikzpicture}
-}
-\end{center}
-\end{frame}
-
-
\section{Competitor analysis}
\begin{frame}{Competitor comparison}
\begin{center} \small
@@ -1090,43 +1160,18 @@ Note:
\end{frame}
-\begin{frame}{Current technical developments}
+\begin{frame}{How to support?}
\begin{itemize}
- \item Improving wallet (error handling, features, browser support)
- \item Ongoing work on exchange auditing
- \item Tutorial for merchants
- \item Tutorial for Web shop integration
+ \item Join: \href{https://lists.gnu.org/mailman/listinfo/address@hidden,
\href{irc://irc.freenode.net/\#taler}{\#taler}
+ \item Coding \& design: \url{https://gnunet.org/bugs/}
+ \item Translation:
\url{https://git.taler.net/www.git/tree/locale/fr/LC_MESSAGES/messages.po}
+ \item Integration: \url{https://docs.taler.net/}
+ \item Donations: \url{https://gnunet.org/ev}
+ \item Funding: \url{https://taler.net/en/investors.html}
\end{itemize}
- \vfill
- \begin{center}
- \url{https://api.taler.net/}
- \end{center}
\end{frame}
-\begin{frame}{Business considerations}
- \begin{itemize}
- \item Exchange needs to be a legal (!) business to operate.
- \item Exchange operator income is from {\em transaction fees}.
- \item Created Taler Systems S.A. in Luxembourg.
- \item Now trying to find partners and financing for startup.
- \end{itemize}
-\end{frame}
-
-
-%\begin{frame}{Community considerations}
-% \begin{itemize}
-% \item Initial accumulation: Who gets to mint currency?
-% \item Speculation: Who controls the money supply?
-% \item Social welfare:
-% \begin{itemize}
-% \item Who gets to set tax rules and rates?
-% \item Who gets to allocate tax revenue?
-% \end{itemize}
-% \end{itemize}
-%\end{frame}
-
-
\begin{frame}{Conclusion}
\begin{center}
{\bf What can we do?}
@@ -1182,6 +1227,13 @@ References:
\end{frame}
+
+
+\end{document}
+
+
+
+
\begin{frame}{Taler {\tt /withdraw/sign}}
% Customer withdrawing coins with blind signatures
% \bigskip
@@ -1520,5 +1572,41 @@ Merchant and exchange see only the public coin $\langle
C, S_{DK}(C) \rangle$.
\end{frame}
+\begin{frame}{Operational security}
+ \begin{center}
+ \resizebox{\textwidth}{!}{
+\begin{tikzpicture}[
+ font=\sffamily,
+ every matrix/.style={ampersand replacement=\&,column sep=2cm,row sep=2cm},
+ source/.style={draw,thick,rounded corners,fill=green!20,inner sep=.3cm},
+ process/.style={draw,thick,circle,fill=blue!20},
+ sink/.style={source,fill=green!20},
+ datastore/.style={draw,very thick,shape=datastore,inner sep=.3cm},
+ dots/.style={gray,scale=2},
+ to/.style={->,>=stealth',shorten
>=1pt,semithick,font=\sffamily\footnotesize},
+ every node/.style={align=center}]
+
+ % Position the nodes using a matrix layout
+ \matrix{
+ \node[source] (wallet) {Wallet};
+ \& \node[process] (browser) {Browser};
+ \& \node[process] (shop) {Web shop};
+ \& \node[sink] (backend) {Taler backend}; \\
+ };
+
+ % Draw the arrows between the nodes and label them.
+ \draw[to] (browser) to[bend right=50] node[midway,above] {(4) signed
contract}
+ node[midway,below] {(signal)} (wallet);
+ \draw[to] (wallet) to[bend right=50] node[midway,above] {(signal)}
+ node[midway,below] {(5) signed coins} (browser);
+ \draw[<->] (browser) -- node[midway,above] {(3,6) custom}
+ node[midway,below] {(HTTPS)} (shop);
+ \draw[to] (shop) to[bend right=50] node[midway,above] {(HTTPS)}
+ node[midway,below] {(1) proposed contract / (7) signed coins} (backend);
+ \draw[to] (backend) to[bend right=50] node[midway,above] {(2) signed
contract / (8) confirmation}
+ node[midway,below] {(HTTPS)} (shop);
+\end{tikzpicture}
+}
+\end{center}
+\end{frame}
-\end{document}
diff --git a/presentations/investors/investors2017ls.tex
b/presentations/investors/investors2017ls.tex
index 9b17ff0..9192007 100644
--- a/presentations/investors/investors2017ls.tex
+++ b/presentations/investors/investors2017ls.tex
@@ -822,6 +822,21 @@ PM $=$ Person month
\end{center}
\end{frame}
+
+\begin{frame}{Potential Synergies between Taler and Blockchains}
+ \begin{block}{What can Blockchains do for Taler?}
+ Taler cannot cryptographically prove the {\bf timing} of
+ transactions. Using a blockchain for {\bf timestamping} would
+ allow GNU Taler to provide hard proof of {\bf when} a payment
+ happened.
+ \end{block}
+ \begin{block}{What can Taler do for Blockchains?}
+ Blockchains have inherently high transaction {\bf costs} and little
+ {\bf privacy}. Taler can operate as a {\bf side-chain}, providing
+ enhanced privacy and {\bf performance} for crypto currencies.
+ \end{block}
+\end{frame}
+
\end{document}
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- [GNUnet-SVN] [taler-marketing] branch master updated (ba8058b -> bf80020),
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