Cashu is Ecash for Bitcoin

Cashu is a free and open-source Chaumian ecash protocol built for Bitcoin. Ecash is a digital bearer token that is stored on a user's device, very similar to physical cash. The Cashu protocol allows you to build applications such as wallets or voucher systems. Cashu is designed to be private, secure and scalable. Transactions are instant and nearly free.

What is Cashu?

Cashu is an ecash protocol that is integrated with the Bitcoin protocol. An Ecash system consists of two parts, the mint and the Ecash wallet. Anyone can run a mint for their application, be it a wallet, a web paywall, paid streaming services, or a voucher and rewards system for a super market. Ecash transactions between users or from the user to a service provider respect the user's privacy. A mint does not store a database of user accounts and their activity which protects users of an Ecash system from leaks their private data to hackers and can provide stronger censorship resistant than classical payment systems.

Explore Cashu

Cryptography

Cashu is an Ecash implementation based on David Wagner's variant of Chaumian blinding.

Protocol

Cashu NUTs (Notation, Usage, and Terminology) are Cashu's protocol specifications and the developer libraries make it easy to write wallets and mints.

Apps

There are many apps that implement the Cashu protocol. Apps are available as mobile apps for iOS and Android, progressive web apps (PWA), and command-line tools (CLI).

Libraries

Cashu libraries are available for various programming languages. Click here to see the full list. Here are some examples.

Join Cashu R&D

We have a Matrix space and a Telegram channel focussed on Cashu R&D. If you're developer, please join us!