From f79f12e7d84578a4ac75f542a09c0aa65e146570 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?=C3=96zg=C3=BCr=20Kesim?= Date: Fri, 31 May 2024 05:44:58 +0200 Subject: [PATCH] added potential misuse; refine image --- .../.$age-restriction-taler.drawio.bkp | 309 +++++++++--------- .../age-restriction-taler.drawio | 35 +- eipsi2024/eipsi2024.tex | 54 +-- 3 files changed, 207 insertions(+), 191 deletions(-) diff --git a/age-restriction.drawio/.$age-restriction-taler.drawio.bkp b/age-restriction.drawio/.$age-restriction-taler.drawio.bkp index fbb486f..4a694d4 100644 --- a/age-restriction.drawio/.$age-restriction-taler.drawio.bkp +++ b/age-restriction.drawio/.$age-restriction-taler.drawio.bkp @@ -1,4 +1,4 @@ - + @@ -689,466 +689,469 @@ - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - - + + - - + + - - + + - - + + - + - + - + - + - + - + - + - + - + - + - + - + - + - + - + + + + diff --git a/age-restriction.drawio/age-restriction-taler.drawio b/age-restriction.drawio/age-restriction-taler.drawio index 7e540b8..89cb319 100644 --- a/age-restriction.drawio/age-restriction-taler.drawio +++ b/age-restriction.drawio/age-restriction-taler.drawio @@ -1,4 +1,4 @@ - + @@ -689,7 +689,7 @@ - + @@ -1086,18 +1086,6 @@ - - - - - - - - - - - - @@ -1113,8 +1101,8 @@ - - + + @@ -1149,6 +1137,21 @@ + + + + + + + + + + + + + + + diff --git a/eipsi2024/eipsi2024.tex b/eipsi2024/eipsi2024.tex index 7896c00..eb8a49d 100644 --- a/eipsi2024/eipsi2024.tex +++ b/eipsi2024/eipsi2024.tex @@ -891,22 +891,6 @@ Searching for functions \uncover<2->{with the following signatures} \end{columns} \end{frame} -\begin{frame}{Instantiation with Edx25519} - But... isn't ECDSA considered to be difficult to implement correctly? - - \pause - We also formally define another signature scheme, Edx25519:\\[1em] - - \begin{itemize} - \item based on EdDSA (Bernstein et al.), - \item generates compatible signatures, - \item allows for key derivation from both, private and public keys, independently and - \item is already in use in GNUnet. - \end{itemize}~\\[1em] - - Current implementation of age restriction in GNU Taler uses Edx25519. -\end{frame} - % \begin{frame}{Instantiation with ECDSA} % \framesubtitle{Full definitions} @@ -1046,8 +1030,7 @@ Searching for functions \uncover<2->{with the following signatures} \section{Discussion \& Conclusion} -\begin{frame}{Discussion} - Technical aspects and challenges +\begin{frame}{Discussion}{Technical aspects and challenges} \begin{itemize}[<+->] \item Our solution can in principle be used with any token-based payment scheme \item[] However, GNU Taler best aligned with our design goals @@ -1063,8 +1046,7 @@ Searching for functions \uncover<2->{with the following signatures} \end{itemize} \end{frame} -\begin{frame}{Discussion} - Legal aspects and applicability +\begin{frame}{Discussion}{Legal aspects and applicability} \begin{itemize}[<+->] \item The scheme only makes sense when cheating can be discouraged, f.e. economically \item There will be limits where the scheme is considered acceptable. @@ -1072,11 +1054,23 @@ Searching for functions \uncover<2->{with the following signatures} \end{itemize} \end{frame} +\begin{frame}{Discussion}{Potential for misuse} + \begin{itemize}[<+->] + \item Instead of age groups, couldn't the scheme encode \textit{arbitrary} semantics? + \item Yes, but \textit{implementation} in GNU Taler only allows for arithmetic comparison + \item Problem already exists with denomitations keys: + \item They could be used to seperate the anonymity set of users. + \vfill + \item GNU Taler defines the role of an \textit{Auditor}: + \item a seperate entity to supervise the operation of the exchange + \end{itemize} +\end{frame} + \begin{frame}{Related Work} \begin{itemize} \item Current privacy-perserving systems all based on - attribute-based credentials (Koning et al., - Schanzenbach et al., Camenisch et al., Au et al.) + attribute-based credentials + % (Koning et al., Schanzenbach et al., Camenisch et al., Au et al.) \item Attribute-based approach lacks support: \begin{itemize} @@ -1237,4 +1231,20 @@ Searching for functions \uncover<2->{with the following signatures} % \end{description} %\end{frame} +\begin{frame}{Instantiation with Edx25519} + But... isn't ECDSA considered to be difficult to implement correctly? + + \pause + We also formally define another signature scheme, Edx25519:\\[1em] + + \begin{itemize} + \item based on EdDSA (Bernstein et al.), + \item generates compatible signatures, + \item allows for key derivation from both, private and public keys, independently and + \item is already in use in GNUnet. + \end{itemize}~\\[1em] + + Current implementation of age restriction in GNU Taler uses Edx25519. +\end{frame} + \end{document}