commit 90064998da3fc9e82acc7352a55429bc45a58d7e
parent 2eea4cc9bed07be7cc83fc3306f45facac325722
Author: Christian Grothoff <christian@grothoff.org>
Date: Wed, 26 Apr 2023 20:33:12 +0200
es versions
Diffstat:
1 file changed, 10 insertions(+), 422 deletions(-)
diff --git a/presentations/comprehensive/boh.tex b/presentations/comprehensive/boh.tex
@@ -262,7 +262,7 @@
\section{What is Taler?}
\begin{frame}{What is Taler?}
- \framesubtitle{\url{https://taler.net/en/features.html}} \noindent
+ \framesubtitle{\url{https://taler.net/es/features.html}} \noindent
Taler is
\vfill
\begin{itemize}
@@ -286,7 +286,7 @@ Taler is
\begin{frame}{Design principles}
- \framesubtitle{https://taler.net/en/principles.html}
+ \framesubtitle{https://taler.net/es/principles.html}
GNU Taler must ...
\begin{enumerate}
\item {... be implemented as {\bf free software} (but {\em available} under a commercial license).}
@@ -335,7 +335,7 @@ positives in fraud detection
\begin{frame}{Taler: Unique Regulatory Features for Central Banks}
- \framesubtitle{\url{https://www.snb.ch/en/mmr/papers/id/working_paper_2021_03}}
+ \framesubtitle{\url{https://taler.net/papers/cbdc2021es.pdf}}
\begin{itemize}
\item Central bank issues digital coins equivalent to issuing cash \\
$\Rightarrow$ monetary policy remains under CB control
@@ -536,9 +536,13 @@ Additionally, I will have a {\bf sabbatical} in Fall/Winter 2023
\framesubtitle{\url{https://taler.net/en/bibliography.html}}
\vfill
References:
-{\tiny
\begin{enumerate}
\item{David Chaum, Christian Grothoff and Thomas Moser.
+ {\em Come una banca centrale dovrebbe emettere una moneta digitale}.
+ {\bf Swiss National Bank Working Papers, 2021}.
+ \url{https://taler.net/papers/cbdc2021es.pdf}}
+{\tiny
+ \item{David Chaum, Christian Grothoff and Thomas Moser.
{\em How to issue a central bank digital currency}.
{\bf SNB Working Papers, 2021}.}
\item{Martin Summer and Hannes Hermanky.
@@ -565,8 +569,9 @@ References:
\item{Marco Boss.
{\em GNU Taler Scalability}.
{\bf BFH, Bachelor's Thesis, 2022}.}
-\end{enumerate}
}
+\end{enumerate}
+\vfill
\end{frame}
@@ -613,420 +618,3 @@ new})
\end{document}
-
-
-
-
-\begin{frame}{Taler {\tt /withdraw/sign}}
-% Customer withdrawing coins with blind signatures
-% \bigskip
- \begin{figure}[th]
- \begin{minipage}[b]{0.45\linewidth}
- \begin{center}
- \begin{tikzpicture}[scale = 0.4,
- transform shape,
- msglabel/.style = { text = Black, yshift = .3cm,
- sloped, midway },
- okmsg/.style = { ->, color = MidnightBlue, thick,
- >=stealth },
- rstmsg/.style = { ->, color = BrickRed, thick,
- >=stealth }
- ]
- \node[draw = MidnightBlue,
- fill = CornflowerBlue,
- minimum width = .3cm,
- minimum height = 10cm
- ] (h1) at (-4, 0) {};
- \node[draw = MidnightBlue,
- fill = CornflowerBlue,
- minimum width = .3cm,
- minimum height = 10cm
- ] (h2) at (4, 0) {};
- \node[above = 0cm of h1] {Wallet};
- \node[above = 0cm of h2] {Exchange};
-
- \path[->, color = MidnightBlue, very thick, >=stealth]
- (-5, 4.5) edge
- node[rotate=90, text = Black, yshift = .3cm] {Time}
- (-5, -4.5);
- \path[okmsg, dashed]
- ($(h1.east)+(0, 4.0)+(0, -1.0)$) edge
- node[msglabel] {SEPA(RK,A)}
- ($(h2.west)+(0, 3.5)+(0, -1.0)$);
- \path[okmsg]
- ($(h1.east)+(0, -1.0)$) edge
- node[msglabel] {POST {\tt /withdraw/sign} $S_{RK}(DK, B_b(C))$}
- ($(h2.west)+(0, -1.5)$);
- \path[okmsg]
- ($(h2.west)+(0, -2.0)$) edge
- node[msglabel] {200 OK: $S_{DK}(B_b(C))$)}
- ($(h1.east)+(0, -2.5)$);
- \path[rstmsg]
- ($(h2.west)+(0, -3.5)$) edge
- node[msglabel] {402 PAYMENT REQUIRED: $S_{RK}(DK, B_b(C))$)}
- ($(h1.east)+(0, -4)$);
- \node at (5.3, 0) {};
- \end{tikzpicture}
- \end{center}
- Result: $\langle c, S_{DK}(C) \rangle$.
- \end{minipage}
- \hspace{0.5cm}
- \begin{minipage}[b]{0.45\linewidth}
- \tiny
- \begin{description}
- \item[$A$] Some amount, $A \ge A_{DK}$
- \item[$RK$] Reserve key
- \item[$DK$] Denomination key
- \item[$b$] Blinding factor
- \item[$B_b()$] RSA-FDH blinding % DK supressed
- \item[$C$] Coin public key $C := cG$
- \item[$S_{RK}()$] EdDSA signature
- \item[$S_{DK}()$] RSA-FDH signature
- \end{description}
- \end{minipage}
- \end{figure}
-\end{frame}
-
-
-\begin{frame}[t]{Taler {\tt /deposit}}
-Merchant and exchange see only the public coin $\langle C, S_{DK}(C) \rangle$.
-\bigskip
- \begin{figure}[th]
- \begin{minipage}[b]{0.45\linewidth}
- \begin{center}
- \begin{tikzpicture}[scale = 0.4,
- transform shape,
- msglabel/.style = { text = Black, yshift = .3cm,
- sloped, midway },
- okmsg/.style = { ->, color = MidnightBlue, thick,
- >=stealth },
- rstmsg/.style = { ->, color = BrickRed, thick,
- >=stealth }
- ]
- \node[draw = MidnightBlue,
- fill = CornflowerBlue,
- minimum width = .3cm,
- minimum height = 10cm
- ] (h1) at (-4, 0) {};
- \node[draw = MidnightBlue,
- fill = CornflowerBlue,
- minimum width = .3cm,
- minimum height = 10cm
- ] (h2) at (4, 0) {};
- \node[above = 0cm of h1] {Merchant};
- \node[above = 0cm of h2] {Exchange};
-
- \path[->, color = MidnightBlue, very thick, >=stealth]
- (-5, 4.5) edge
- node[rotate=90, text = Black, yshift = .3cm] {Time}
- (-5, -4.5);
- \path[->, color = MidnightBlue, thick, >=stealth]
- ($(h1.east)+(0,3)$) edge
- node[text = Black, yshift = .3cm, sloped] {POST {\tt /deposit} $S_{DK}(C), S_{c}(D)$}
- ($(h2.west)+(0,2)$);
- \path[->, color = MidnightBlue, thick, >=stealth]
- ($(h2.west)+(0,0.5)$) edge
- node[text = Black, yshift = .3cm, sloped] {200 OK: $S_{SK}(S_{c}(D))$}
- ($(h1.east)+(0,-0.5)$);
- \path[rstmsg]
- ($(h2.west)+(0, -2.5)$) edge
- node[msglabel] {409 CONFLICT: $S_{c}(D')$}
- ($(h1.east)+(0, -3.5)$);
- \node at (5.3, 0) {};
- \end{tikzpicture}
- \end{center}
- \end{minipage}
- \hspace{0.5cm}
- \begin{minipage}[b]{0.45\linewidth}
- \tiny
- \begin{description}
- \item[$DK$] Denomination key
- \item[$S_{DK}()$] RSA-FDH signature using $DK$
- \item[$c$] Private coin key, $C := cG$.
- \item[$S_{C}()$] EdDSA signature using $c$
- \item[$D$] Deposit details
- \item[$SK$] Exchange's signing key
- \item[$S_{SK}()$] EdDSA signature using $SK$
- \item[$D'$] Conficting deposit details $D' \not= D$
- \end{description}
- \end{minipage}
- \end{figure}
-\end{frame}
-
-
-\begin{frame}{Taler {\tt /refresh/melt}}
- \begin{figure}[th]
- \begin{minipage}[b]{0.45\linewidth}
- \begin{center}
- \begin{tikzpicture}[scale = 0.4,
- transform shape,
- msglabel/.style = { text = Black, yshift = .3cm,
- sloped, midway },
- okmsg/.style = { ->, color = MidnightBlue, thick,
- >=stealth },
- rstmsg/.style = { ->, color = BrickRed, thick,
- >=stealth }
- ]
- \node[draw = MidnightBlue,
- fill = CornflowerBlue,
- minimum width = .3cm,
- minimum height = 10cm
- ] (h1) at (-4, 0) {};
- \node[draw = MidnightBlue,
- fill = CornflowerBlue,
- minimum width = .3cm,
- minimum height = 10cm
- ] (h2) at (4, 0) {};
- \node[above = 0cm of h1] {Customer};
- \node[above = 0cm of h2] {Exchange};
-
- \path[->, color = MidnightBlue, very thick, >=stealth]
- (-5, 4.5) edge
- node[rotate=90, text = Black, yshift = .3cm] {Time}
- (-5, -4.5);
- \path[->, color = MidnightBlue, thick, >=stealth]
- ($(h1.east)+(0,3)$) edge
- node[text = Black, yshift = .3cm, sloped] {POST {\tt /refresh/melt} $S_{DK}(C), S_c({\cal DK}, {\cal T},{\cal B})$}
- ($(h2.west)+(0,2)$);
- \path[->, color = MidnightBlue, thick, >=stealth]
- ($(h2.west)+(0,0.5)$) edge
- node[text = Black, yshift = .3cm, sloped] {200 OK: $S_{SK}(H({\cal T}, {\cal B}),\gamma)$}
- ($(h1.east)+(0,-0.5)$);
- \path[rstmsg]
- ($(h2.west)+(0, -2.5)$) edge
- node[msglabel] {409 CONFLICT: $S_{C}(X), \ldots$}
- ($(h1.east)+(0, -3.5)$);
- \node at (5.3, 0) {};
- \end{tikzpicture}
- \end{center}
- \end{minipage}
- \hspace{0.5cm}
- \begin{minipage}[b]{0.45\linewidth}
- \tiny
- \begin{description}
- \item[$\kappa$] System-wide security parameter, usually 3.
- \\ \smallskip
- \item[$\cal DK$] $:= [DK^{(i)}]_i$ \\ List of denomination keys \\
- $D + \sum_i A_{DK^{(i)}} < A_{DK}$
- \item[$t_j$] Random scalar for $j<\kappa$
- \item[${\cal T}$] $:= [T_j]_\kappa$ where $T_j = t_j G$
- \item[$k_j$] $:= c T_j = t_j C$ is an ECDHE
- \item[$b_j^{(i)}$] $:= KDF_b(k_j,i)$ % blinding factor
- \item[$c_j^{(i)}$] $:= KDF_c(k_j,i)$ % coin secret keys
- \item[$C_j^{(i)}$] $: = c_j^{(i)} G$ % new coin publics % keys
- \item[${\cal B}$] $:= [H( \beta_j )]_\kappa$ where \\
- $\beta_j := \left[ B_{b_j^{(i)}}(C_j^{(i)}) \right]_i$
- \\ \smallskip
- \item[$\gamma$] Random value in $[0,\kappa)$
-% \\ \smallskip
-% \item[$X$] Deposit or refresh
- \end{description}
- \end{minipage}
- \end{figure}
-\end{frame}
-
-
-\begin{frame}{Taler {\tt /refresh/reveal}}
- \begin{figure}[th]
- \begin{minipage}[b]{0.45\linewidth}
- \begin{center}
- \begin{tikzpicture}[scale = 0.4,
- transform shape,
- msglabel/.style = { text = Black, yshift = .3cm,
- sloped, midway },
- okmsg/.style = { ->, color = MidnightBlue, thick,
- >=stealth },
- rstmsg/.style = { ->, color = BrickRed, thick,
- >=stealth }
- ]
- \node[draw = MidnightBlue,
- fill = CornflowerBlue,
- minimum width = .3cm,
- minimum height = 10cm
- ] (h1) at (-4, 0) {};
- \node[draw = MidnightBlue,
- fill = CornflowerBlue,
- minimum width = .3cm,
- minimum height = 10cm
- ] (h2) at (4, 0) {};
- \node[above = 0cm of h1] {Customer};
- \node[above = 0cm of h2] {Exchange};
-
- \path[->, color = MidnightBlue, very thick, >=stealth]
- (-5, 4.5) edge
- node[rotate=90, text = Black, yshift = .3cm] {Time}
- (-5, -4.5);
- \path[->, color = MidnightBlue, thick, >=stealth]
- ($(h1.east)+(0,3)$) edge
- node[text = Black, yshift = .3cm, sloped] {POST {\tt /refresh/reveal} $H({\cal T}, {\cal B}), {\tilde{\cal T}}, \beta_\gamma$}
- ($(h2.west)+(0,2)$);
- \path[->, color = MidnightBlue, thick, >=stealth]
- ($(h2.west)+(0,0.5)$) edge
- node[text = Black, yshift = .3cm, sloped] {200 OK: $\cal S$}
- ($(h1.east)+(0,-0.5)$);
- \path[rstmsg]
- ($(h2.west)+(0, -2.5)$) edge
- node[msglabel] {400 BAD REQUEST: $Z$}
- ($(h1.east)+(0, -3.5)$);
- \node at (5.3, 0) {};
- \end{tikzpicture}
- \end{center}
- \end{minipage}
- \hspace{0.5cm}
- \begin{minipage}[b]{0.45\linewidth}
- \tiny
- \begin{description}
- \item[$\cal DK$] $:= [DK^{(i)}]_i$
- \item[$t_j$] .. \\ \smallskip
-
- \item[$\tilde{\cal T}$] $:= [t_j | j \in \kappa, j \neq \gamma]$ \\ \smallskip
-
- \item[$k_\gamma$] $:= c T_\gamma = t_\gamma C$
- \item[$b_\gamma^{(i)}$] $:= KDF_b(k_\gamma,i)$
- \item[$c_\gamma^{(i)}$] $:= KDF_c(k_\gamma,i)$
- \item[$C_\gamma^{(i)}$] $: = c_\gamma^{(i)} G$
-
- \item[$B_\gamma^{(i)}$] $:= B_{b_\gamma^{(i)}}(C_\gamma^{(i)})$
- \item[$\beta_\gamma$] $:= \big[ B_\gamma^{(i)} \big]_i$
- \item[$\cal S$] $:= \left[ S_{DK^{(i)}}( B_\gamma^{(i)} ) \right]_i$ \\ \smallskip
-
- \item[$Z$] Cut-and-choose missmatch information
- \end{description}
- \end{minipage}
- \end{figure}
-\end{frame}
-
-
-\begin{frame}{Taler {\tt /refresh/link}}
- \begin{figure}[th]
- \begin{minipage}[b]{0.45\linewidth}
- \begin{center}
- \begin{tikzpicture}[scale = 0.4,
- transform shape,
- msglabel/.style = { text = Black, yshift = .3cm,
- sloped, midway },
- okmsg/.style = { ->, color = MidnightBlue, thick,
- >=stealth },
- rstmsg/.style = { ->, color = BrickRed, thick,
- >=stealth }
- ]
- \node[draw = MidnightBlue,
- fill = CornflowerBlue,
- minimum width = .3cm,
- minimum height = 10cm
- ] (h1) at (-4, 0) {};
- \node[draw = MidnightBlue,
- fill = CornflowerBlue,
- minimum width = .3cm,
- minimum height = 10cm
- ] (h2) at (4, 0) {};
- \node[above = 0cm of h1] {Customer};
- \node[above = 0cm of h2] {Exchagne};
-
- \path[->, color = MidnightBlue, very thick, >=stealth]
- (-5, 4.5) edge
- node[rotate=90, text = Black, yshift = .3cm] {Time}
- (-5, -4.5);
- \path[->, color = MidnightBlue, thick, >=stealth]
- ($(h1.east)+(0,3)$) edge
- node[text = Black, yshift = .3cm, sloped] {POST {\tt /refresh/link} $C$}
- ($(h2.west)+(0,2)$);
- \path[->, color = MidnightBlue, thick, >=stealth]
- ($(h2.west)+(0,0.5)$) edge
- node[text = Black, yshift = .3cm, sloped] {200 OK: $T_\gamma$}
- ($(h1.east)+(0,-0.5)$);
- \path[rstmsg]
- ($(h2.west)+(0, -2.5)$) edge
- node[msglabel] {404 NOT FOUND}
- ($(h1.east)+(0, -3.5)$);
- \node at (5.3, 0) {};
- \end{tikzpicture}
- \end{center}
- \end{minipage}
- \hspace{0.5cm}
- \begin{minipage}[b]{0.45\linewidth}
- \tiny
- \begin{description}
- \item[$C$] Old coind public key \\ \smallskip
- \item[$T_\gamma$] Linkage data $\cal L$ at $\gamma$
- \end{description}
- \end{minipage}
- \end{figure}
-\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}
-
-
-\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 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}{Use Case: Anti-Spam}
- \framesubtitle{Background: \url{https://pep.security/}}
- Today, p$\equiv$p provides authenticated encryption for e-mail:
- \begin{itemize}
- \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}
-\end{frame}
