From 9e694994681b0b2861553d0a50bca6623b546dd2 Mon Sep 17 00:00:00 2001 From: Gian Demarmels Date: Mon, 14 Feb 2022 00:03:06 +0100 Subject: CS thesis --- doc/cs/ads/abstract.tex | 26 ++++++++++++++++++++++++++ 1 file changed, 26 insertions(+) create mode 100644 doc/cs/ads/abstract.tex (limited to 'doc/cs/ads/abstract.tex') diff --git a/doc/cs/ads/abstract.tex b/doc/cs/ads/abstract.tex new file mode 100644 index 000000000..0610eb10b --- /dev/null +++ b/doc/cs/ads/abstract.tex @@ -0,0 +1,26 @@ +\chapter*{Abstract} +GNU Taler is an intuitive, fast and socially responsible digital payment system implemented as free software. +While preserving the customers privacy, GNU Taler is still compliant to regulations. +\\\\ +The goal of this thesis is to improve Taler's performance and provide cipher agility by adding support for Schnorr's blind signatures. +To achieve this goal, the current state in research for Schnorr signatures needs to be analyzed. +After choosing a signature scheme, it has to be integrated into the Taler protocols. +Besides implementing the redesigned protocols in Taler, an implementation of the cryptographic routines is needed. +\\\\ +The paper "Blind Schnorr +Signatures and Signed ElGamal Encryption in the Algebraic Group Model" \cite{cryptoeprint:2019:877} from 2019 (updated in 2021) introducing \gls{CSBS} is used as theoretical basis for our improvements. +The paper explains why simple Blind Schnorr Signatures are broken and how the Clause Schnorr Blind Signature scheme is secured against this attack.\\ +Compared to the currently used \gls{RSABS}, the new scheme has an additional request, two blinding factors instead of one and many calculations are done twice to prevent attacks. +\\\\ +The Taler protocols were redesigned to support the Clause Blind Schnorr Signature scheme, including slight alterations to ensure \textit{abort-idempotency}, and then further specified. +Before starting with the implementation of the redesigned protocols, the cryptographic routines for \gls{CSBS} were implemented as part of the thesis. \\ +All of the implemented code is tested and benchmarks are added for the cryptographic routines. +\\\\ +Multiple results were achieved during this thesis: +The redesigned protocols Taler protocols with support for \gls{CSBS}, the implementation of the cryptographic routines, the implementation of Talers core protocols and a detailed comparison between \gls{RSABS} and \gls{CSBS}. +Overall, the \gls{CSBS} are significantly faster, require less disk space, and bandwidth and provide \textit{cipher agility} for Taler. + +\section*{Acknowledgement} +We would like to kindly thank Christian Grothoff (Bern University of Applied Sciences) for his extensive advice, support and very helpful feedback during our whole thesis.\\ +We also kindly thank Jeffrey Burdges (Web 3, Switzerland) for reviewing the proposal containing the redesigned protocols and giving feedback.\\ +Further, we kindly thank Jacob Appelbaum (Bern University of Applied Sciences, Eindhoven University of Technology) for further results for the performance measurements of our cryptographic routines and the insightful conversations. -- cgit v1.2.3