\begin{abstract}
This bachelor thesis describes and implements a theoretical contcept of a donation authority system. The donation authority or in short Donau is privacy friendly and free software. It examines the usability by asking a tax authority about their current donation system and obtaining their opinion on the Donau project. Donau is a GNU Taler project. It depends on the code of the GNU Taler environment, but is completely independent of the Taler payment system.

The Donau environment includes three stakeholder. Donors, charities and of course the tax authority. The centerpiece, the Donau, would be operated by the tax authority itself. The Donau issues donation receipts for the Donor via charity and validates the receipts from the donor. Issuance by the authority prevents possible donation receipt forgeries. The automation of the donation receipt validation process would also allow the donor's various donation receipts to be combined into one. Donation data is often sensitive data. Therefore, in order to protect the donor, the system is designed to collect and store as little data as possible and to anonymize the data where possible.

results...
\end{abstract}
