commit 8771a2231bc9989665a9a1411a3d8bcaa64a4653 parent 4f2afb356fcab813b328c2d11100ff7200a2c68f Author: Matyja Lukas Adam <lukas.matyja@students.bfh.ch> Date: Thu, 6 Jun 2024 18:40:45 +0200 clean up Diffstat:
6 files changed, 7 insertions(+), 7 deletions(-)
diff --git a/doc/thesis/chapters/background/blindsign.tex b/doc/thesis/chapters/background/blindsign.tex @@ -1,7 +1,7 @@ \section{Blind Signatures}\label{blind_signatures} One important cryptographic scheme used by the Donau is the blind signature scheme. It is an extension of digital signatures which provides besides authenticity and non-repudiation privacy by allowing a user to obtain a signature for a message, without revealing the contents of the message to the signer. All cryptographic elements used by the Donau where privided by the GNU Taler libraries. -This section only provides an overview of blinded signatures. Detailed information about blinded signature can be found at \url{https://taler.net/papers/cs-thesis.pdf}. Blinded signatures are the key elements to reach privacy for the donor (see chapter xx). With blinded signatures a blinded unrecognizable message was signed. Only the creator of the blinded message is able to unblind the signature and therefore to receive a valid signature for the unblinded message. The Donau system uses blinded signatures to bind the identity to a donation receipt while hiding the identity of the donor. As a result of the property of blindness, the blind signer Donau is not able to link the cleartext message with the made blind signature or the blind with the unblind signature \cite[p.12]{cryptoeprint:2019/877}. There are multiple blind signature schemes. The Donau distinguishes the following two equivalent blind signature schemes: +This section only provides an overview of blinded signatures. Detailed information about blinded signature can be found at \url{https://taler.net/papers/cs-thesis.pdf}. Blinded signatures are the key elements to reach privacy for the donor (see chapter \ref{issuing_donation_receipts}). With blinded signatures a blinded unrecognizable message was signed. Only the creator of the blinded message is able to unblind the signature and therefore to receive a valid signature for the unblinded message. The Donau system uses blinded signatures to bind the identity to a donation receipt while hiding the identity of the donor. As a result of the property of blindness, the blind signer Donau is not able to link the cleartext message with the made blind signature or the blind with the unblind signature \cite[p.12]{cryptoeprint:2019/877}. There are multiple blind signature schemes. The Donau distinguishes the following two equivalent blind signature schemes: \subsection{RSA}\label{rsa} Concrete the RSA-FDH blind signatures are used. Before blinding, to eliminate certain attacks, a Full-Domain Hash on the message is applied. Full-Domain means the hash has the same size as the RSA modulus. The blind signature scheme is similar to the normal RSA signatur scheme. In addition to the normal scheme, the message is blinded with an private and random value. Practically the length of the modulus and therefore for the key size, signature size and the security level is variable. The scheme only has one round trip.\cite{nigelcrypto:2016} diff --git a/doc/thesis/chapters/background/taler.tex b/doc/thesis/chapters/background/taler.tex @@ -3,6 +3,6 @@ GNU Taler is an open protocol for electronic payment system using blind signatur One key component of the GNU Taler payment system is the exchange which is responsible for exchanging existing money into electronic money. Customers can retrieve funds from the exchange to make anonymous payments. The merchant is not anonymous and thus can not hide the income. This helps to avoid tax evasion and money laundering \cite{Taler}. GNU Taler uses denominations to represent the values of a coins. A denomination contains the unit of currency and the face value of a given coin. Each denomination contains a cryptographic public key used by the exchange to verify the denomination. -%...maybe not in background but intro? +%...maybe not in background but intro?->no too technical, better here The Donau is based on the exchange and requires some of its parts to function. The concept of the denomination was adapted into the donation units, which are used to represent the face value of a donation. diff --git a/doc/thesis/chapters/implementation/donau.tex b/doc/thesis/chapters/implementation/donau.tex @@ -62,7 +62,7 @@ The response includes the charity ID generated by the database. \subsubsection{\texttt{/batch-issue}} %TODO describe BUDI, donation unit -> glossary? -Only recognized charities requesting issue receipts for their donors (see section xx). An post issue receipt request includes an array of BUDI-Key-Pairs. A BUDI-Key-Pair consists of a BUDI and a hash of a public donation unit key. The charity also signs the request with an EdDSA private key. The corresponding public key was given to the Donau at the registration of the charity. After the Donau checked the signature from the charity it signs the BUDIs with the corresponding donation unit private key. Before the signatures are returned to the charity the Donau saves a hash of the request and all donation unit signatures to make the request idempotent (see database section). +Only recognized charities are allowed to request issue receipts for their donors (see section \ref{validation}). An post issue receipt request includes an array of BUDI-Key-Pairs. A BUDI-Key-Pair consists of a BUDI and a hash of a public donation unit key. The charity also signs the request with an EdDSA private key. The corresponding public key was given to the Donau at the registration of the charity. After the Donau checked the signature from the charity it signs the BUDIs with the corresponding donation unit private key. Before the signatures are returned to the charity the Donau saves a hash of the request and all donation unit signatures to make the request idempotent (see database section). \begin{figure}[ht] \includegraphics[width=1\textwidth]{donau_flow_issue_receipt} diff --git a/doc/thesis/chapters/introduction/interview.tex b/doc/thesis/chapters/introduction/interview.tex diff --git a/doc/thesis/chapters/introduction/scope.tex b/doc/thesis/chapters/introduction/scope.tex @@ -1,10 +1,10 @@ \section{Scope}\label{scope} -At the start of the project we wrote the REST API specifications together with the database schema and the Donau protocol. -Later tests were written to ensure that the endpoints work correctly without any errors. -During the project we documented the code and created various other documents like presentations and project summaries. +At the start of the project we wrote the REST API specifications together with the database schema for the Donau and the Donau protocol. +While implementing the Donau tests were written to ensure that the endpoints work correctly. +During the project the code was documented and various other documents like presentations and project summaries and a short film were created. To demonstrate the Donau we developped an Android application that can verify donations by scanning a QR-Code. -We also held an interview with the tax authority Zürich, which has provided valuable insight in how donations are verified and important aspects that a system like the Donau should fulfil. +We also held an interview with the tax authority Zürich, which has provided valuable insight in how donations are verified and important aspects that a system like the Donau should fulfill. Out of scope was the charity implementation which would have been integrated into the Taler merchant and the donor client implementation which would have been integrated into the Taler wallet. Unlike the charity integration, the donor part of the taler wallet is payment system dependent. In other words, since the taler wallet can only make donations with the taler payment system, it could only receive donation receipts for this. The administrator interface was also not realized, which would have provided a user-friendly interface to manage the charities. diff --git a/doc/thesis/thesis.pdf b/doc/thesis/thesis.pdf Binary files differ.