goal.tex (1662B)
1 \section{Goal} 2 3 The objective of this thesis is to develop and implement a framework for the cashless withdrawal of digital cash in GNU Taler. The framework implements the process that digital cash in GNU Taler can be withdrawn at a terminal of an established payment service provider. The withdrawal process on the side of the provider terminal is implemented on the Paydroid platform, which is supplied by the payment provider \textit{Wallee}. 4 5 The framework aims to achieve the following key objectives: 6 7 \begin{enumerate} 8 \label{sec-goals-properties} 9 \item Finality: The operator of the Taler Exchange is not liable for any losses incurred in connection with the payment. 10 \item Convenience: The user experience adheres to established patterns. 11 \item Abort: The payment flow is robust and secure, and the option to abort transactions without the loss of money is available. 12 \end{enumerate} 13 14 \subsection{cashless2ecash (C2EC)} 15 16 To achieve these goals C2EC is implemented as part of GNU Taler. C2EC mediates between the Taler Exchange and the terminal provider. This includes checking that the transaction of the debitor reaches the account of the Exchange and the digital cash can be withdrawn by the user using their wallet. 17 18 \subsection{Paydroid Payment Terminal} 19 20 The Wallee payment terminal, interfaces with payment cards (credit cards, debit cards) and other means of payment (e.g. Twint) to make electronic fund transfers, i.e. a fund transfer to a given GNU Taler Exchange. For our purpose, we extend the functionality of the terminal to initiate the corresponding counter payment from the Exchange to the GNU Taler wallet of the payee.