Cashless to e-Cash

Enabling withdrawal of digital cash through third parties in GNU Taler

During his bachelor thesis, Joel Häberli designed and implemented a framework allowing for cashless withdrawals in GNU Taler.


This thesis develops and implements a framework that allows for cashless withdrawals using GNU Taler, with the objective of increasing the easy onboarding and acceptance of GNU Taler as payment system. Currently, the GNU Taler payment system permits the withdrawal of digital cash using different means of payment. However, GNU Taler currently lacks the possibility using cashless payment means such as credit cards to withdraw digital cash. To address this gap, this thesis introduces a novel component, called cashless2ecash (C2EC), which establishes a reliable connection between the Taler ecosystem and payment service provider’s terminals. The reference implementation establishes the process between the payment service provider Wallee and the GNU Taler Exchange by implementing the new Terminals API in C2EC. The implemented process guarantees the finality of the transaction to the GNU Taler Exchange and the terminal operator. The finality enables the withdrawal of digital cash using GNU Taler without the use of cash. The liability for the transaction is borne by the payment service provider, which assumes the guarantees for the GNU Taler Exchange.

Introduction video

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