Apply

Cashu

A Chaumian ecash protocol for Bitcoin, where a mint issues blinded tokens backed by sats on Lightning.

Cashu is an open protocol for Chaumian ecash on top of Bitcoin. A user deposits sats with a mint over Lightning and receives blinded tokens in return. The tokens can be sent peer to peer as strings or QR codes, and later redeemed at the same mint for Lightning sats.

Because the mint signs tokens blindly, it cannot link a redemption to the original deposit. The mint is still a trusted party for custody: it holds the underlying sats and can refuse to redeem. Cashu does not try to remove that trust, it tries to make each mint small, replaceable, and easy to run.

The specification is maintained as a set of NUTs at cashu.space. There are several interoperable mint and wallet implementations, including Nutshell, CDK, and cashu-ts.

References