Warning This project is in early development, it does however work with real sats! Always use amounts you don't mind losing.

Cashu Development Kit

CDK is a collection of rust crates for Cashu wallets and mints written in Rust.

ALPHA This library is in early development, the api will change and should be used with caution.

Project structure

The project is split up into several crates in the crates/ directory:

• Libraries:
  • cdk: Rust implementation of Cashu protocol.
  • cdk-sqlite: SQLite Storage backend.
  • cdk-redb: Redb Storage backend.
  • cdk-rexie: Rexie Storage backend for browsers.
  • cdk-axum: Axum webserver for mint.
  • cdk-cln: CLN Lightning backend for mint.
  • cdk-lnd: Lnd Lightning backend for mint.
  • cdk-lnbits: LNbits Lightning backend for mint.
  • cdk-fake-wallet: Fake Lightning backend for mint. To be used only for testing, quotes are automatically filled.
  • cdk-mint-rpc: Mint management gRPC server and cli.
• Binaries:
  • cdk-cli: Cashu wallet CLI.
  • cdk-mintd: Cashu Mint Binary.
  • cdk-mint-cli: Cashu Mint managemtn gRPC client cli.

Development

For a guide to settings up a development environment see DEVELOPMENT.md

Code Style Guidelines

• Large Enum Variants: When an enum variant contains a large type (>100 bytes), box it using Box<T> to reduce the overall enum size. This improves memory efficiency, especially for error types.

  // Instead of this:
  enum Error {
      SomeLargeError(LargeType),  // LargeType is >100 bytes
  }
  
  // Do this:
  enum Error {
      SomeLargeError(Box<LargeType>),
  }

Implemented NUTs:

Mandatory

NUT #	Description
00	Cryptography and Models
01	Mint public keys
02	Keysets and fees
03	Swapping tokens
04	Minting tokens
05	Melting tokens
06	Mint info

Optional

#	Description	Status
07	Token state check	✔️
08	Overpaid Lightning fees	✔️
09	Signature restore	✔️
10	Spending conditions	✔️
11	Pay-To-Pubkey (P2PK)	✔️
12	DLEQ proofs	✔️
13	Deterministic secrets	✔️
14	Hashed Timelock Contracts (HTLCs)	✔️
15	Partial multi-path payments (MPP)	✔️
16	Animated QR codes	❌
17	WebSocket subscriptions	✔️
18	Payment Requests	✔️
19	Cached responses	✔️
20	Signature on Mint Quote	✔️

Bindings

Experimental JS bindings can be found in the bindings repository.

License

Code is under the MIT License

Contribution

All contributions are welcome.

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, shall be licensed as above, without any additional terms or conditions.

Please see the development guide.