GNU Taler preserving privacy on electronic payment systems using digital coins stored in self-custody on user’s devices

Christian Grothoff
Christian Grothoff, CEO of Taler Systems

Taler Systems SA is a technology company specialising in creating free software for digital payment systems. Our flagship product, the GNU Taler System, is a privacy-respecting digital payment system with built-in age restrictions that allows for fast and secure transactions with anonymity for the buyer. The Taler system uses established cryptography, ensuring that transactions are processed quickly and securely with user privacy. This makes the GNU Taler system ideal for use in various industries, including e-commerce, micropayments, and the sharing economy. The GNU Taler system is highly scalable, allowing it to handle many transactions per second on cheap and power-saving hardware.

Overall, the GNU Taler system offers a unique solution for anyone looking to securely and anonymously process digital payments in the spirit of GDPR. GNU Taler works for standard and crypto-currencies.

How did the project begin?

Working on a decentralized privacy-preserving Next Generation Internet, it was clear that we needed a privacy-preserving payment system. However, blockchains were not a socially desirable solution due to their high environmental and social cost.

Did you have a concept of your final project idea, or did it evolve during the process?

We have over time, added various features based on ideas from the team or requirements brought to us from third parties, but the basic idea of building a privacy-preserving payment system has remained unchanged.

GNU Taler Team

Meet the team

We are a global community of Free Software developers and privacy activists with roots in the GNU project. We have contributors of all genders from ages 14 to 70 years and over a dozen countries speaking various natural and programming languages, trying to follow the culture of the GNU way of communicating.

GNU Taler has repeatedly received support from NGI
funded the first external security audit of the protocol and core implementation, the integration into the e-commerce solution WooCommerce with usability studies, scalability experiments on the Grid5000, age-restrictions, escrow and peer-to-peer payments, accessibility reviews to ensure the payment system is usable by blind people and is providing ongoing funding for enhancements to support regional currencies and the development of a Taler wallet on iOS.

How did you learn about NGI?

We probably first learned about NGI during consultations that resulted in the inception of the NGI program.

What was the status of your project/technology situation before applying for NGI funding?

At the time of our first NGI funding for GNU Taler, we had a first working prototype with academic publications backing the idea but no external reviews of the Taler-specific code.

Will you be taking the idea further now that the support from NGI is over? Please outline a little about how the project continues to be used or to evolve.

NGI support is still ongoing, and we hope that with continued support, we will be able to bring GNU Taler into the European market as a payment solution operated by retail or central banks.

What is the advantage of being part of the NGI community?

Among NGI projects, what is great is that we find mutual respect for certain core values (Free Software, informational self-determination). And with respect to the NGI administration organizations, we appreciate the reasonably fast decisions and low administrative overheads.

What is unique about the NGI community?

We appreciate that Libre Software is a respected core value that has no boundaries for collaboration among NGI projects, and no one asks us to justify business plans based on Libre Software licensing and support models.

How do you support women in STEM?

The GNU Project encourages contributions from anyone who wishes to advance the development of the GNU system, regardless of gender, race, ethnic group, physical appearance, religion, cultural background, and any other demographic characteristics, as well as personal political views. We do not have a special treatment when it comes to gender, we welcome talented, enthusiastic and motivated folks from all genders and parts of the world.

How has the community used the tool for open source software?

Operating GNU Taler, in general, is expected to require an e-money issuer license. We are still adding required AML and KYC features that seem necessary before anyone can legally use the payment system at scale. However, members of the community have already successfully used the payment system to handle payments for drinks at a conference and it is also in limited operation at the BFH.

Taler Systems vending machine
Taler Systems vending machine

Could you explain in simple terms what is new and original in your project?

GNU Taler offers one-sided privacy, where the person making a payment remains anonymous to the other party and the payment system operators, while anyone receiving payments can be easily identified by the operator. This prevents mass surveillance in the private domain (where we spend money) while preventing criminals from using the system to receive money for illegal business activities or evading taxation.

What problem does your project solve?

There is no privacy-preserving, usable, efficient and legal payment system for the Internet.

Please explain a little about any marketing or business development initiatives around the project?

Taler Systems SA is a start-up dedicated to further developing and commercially supporting the GNU Taler software.

Towards the end of the project, what was the evolution of the idea?

Initially, we focused on the protocols, then the user interfaces, and now we are focusing more on community-requested features, performance and compliance.

Where do you see yourself in 5/10 years?

In 10 years, GNU Taler will either be the technology backing the Digital Euro, or GNU Taler, will be the technology that made the Digital Euro project of the European Central Bank obsolete, or we will be “enjoying” life without liberty under a government in absolute control.

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