rust-cktap 0.3.0

A Rust implementation of the Coinkite Tap Protocol (cktap) for use with SATSCARD, TAPSIGNER, and SATSCHIP products.
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# rust-cktap

[![License](https://img.shields.io/badge/license-MIT%2FApache--2.0-blue.svg)](https://github.com/bitcoindevkit/rust-cktap/blob/master/LICENSE)
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[![rustc](https://img.shields.io/badge/rustc-1.85.0%2B-lightgrey.svg)](https://blog.rust-lang.org/2025/02/20/Rust-1.85.0/)

A Rust implementation of the [Coinkite Tap Protocol](https://github.com/coinkite/coinkite-tap-proto) (cktap)
for use with [SATSCARD], [TAPSIGNER], and [SATSCHIP] products.

This project provides PC/SC APDU message encoding and decoding, cvc authentication, certificate chain verification, and card response verification.

It is up to the crate user to send and receive the raw cktap APDU messages via NFC to the card by implementing the `CkTransport` trait. An example implementation is provided using the optional rust `pcsc` crate. Mobile users are expected to implement `CkTransport` using the iOS or Android provided libraries.

### Supported Features

- [x] [IOS Applet Select](https://github.com/coinkite/coinkite-tap-proto/blob/master/docs/protocol.md#first-step-iso-applet-select)
- [x] [CVC Authentication](https://github.com/coinkite/coinkite-tap-proto/blob/master/docs/protocol.md#authenticating-commands-with-cvc)

#### Shared Commands

- [x] [status](https://github.com/coinkite/coinkite-tap-proto/blob/master/docs/protocol.md#status)
- [x] [read](https://github.com/coinkite/coinkite-tap-proto/blob/master/docs/protocol.md#read)
  - [x] response verification
- [x] [derive](https://github.com/coinkite/coinkite-tap-proto/blob/master/docs/protocol.md#derive)
  - [ ] response verification
- [x] [certs](https://github.com/coinkite/coinkite-tap-proto/blob/master/docs/protocol.md#certs)
- [x] [new](https://github.com/coinkite/coinkite-tap-proto/blob/master/docs/protocol.md#new)
- [x] [nfc](https://github.com/coinkite/coinkite-tap-proto/blob/master/docs/protocol.md#nfc)
- [x] [sign](https://github.com/coinkite/coinkite-tap-proto/blob/master/docs/protocol.md#sign)
  - [x] response verification
- [x] [wait](https://github.com/coinkite/coinkite-tap-proto/blob/master/docs/protocol.md#wait)

#### SATSCARD-Only Commands

- [x] [unseal](https://github.com/coinkite/coinkite-tap-proto/blob/master/docs/protocol.md#unseal)
- [x] [dump](https://github.com/coinkite/coinkite-tap-proto/blob/master/docs/protocol.md#dump)

#### TAPSIGNER-Only Commands

- [x] [change](https://github.com/coinkite/coinkite-tap-proto/blob/master/docs/protocol.md#change)
- [x] [xpub](https://github.com/coinkite/coinkite-tap-proto/blob/master/docs/protocol.md#xpub)
- [x] [backup](https://github.com/coinkite/coinkite-tap-proto/blob/master/docs/protocol.md#backup)

### Automated and CLI Testing with Emulator

#### Prerequisites

1. Install dependencies for [cktap emulator](https://github.com/coinkite/coinkite-tap-proto/blob/master/emulator/README.md)

#### Run tests with emulator

```
just test
```

#### Run CLI with emulated card reader

```
just start # for SATSCARD emulator
just start -t # for TAPSIGNER emulator
just run_emu --help
just run_emu certs
just run_emu read
just stop # stop emulator
```

### Manual Testing with real cards

#### Prerequisites

1. Get USB PCSC NFC card reader, for example:
   - [OMNIKEY 5022 CL](https://www.hidglobal.com/products/omnikey-5022-reader)
2. Get Coinkite SATSCARD, TAPSIGNER, or SATSCHIP cards
3. Install card reader PCSC driver
4. Connect USB PCSC NFC reader to desktop system
5. Place SATSCARD, TAPSIGNER, or SATSCHIP on reader

#### Run CLI with desktop USB PCSC NFC card reader

```
just run -- --help
just run certs
just run read
```

## Swift Package

Swift bindings are distributed from this repo as a Swift Package. Once a
release includes `cktapFFI.xcframework.zip`, add the repository URL in Xcode
and use the `CKTap` product.

See `cktap-swift/README.md` for local development and release steps.

## Minimum Supported Rust Version (MSRV)

This library should always compile with any valid combination of features on Rust **1.85.0**.

## License

Licensed under either of

* Apache License, Version 2.0, ([LICENSE-APACHE](LICENSE-APACHE) or <https://www.apache.org/licenses/LICENSE-2.0>)
* MIT license ([LICENSE-MIT](LICENSE-MIT) or <https://opensource.org/licenses/MIT>)

at your option.

## Contribution

Unless you explicitly state otherwise, any contribution intentionally
submitted for inclusion in the work by you, as defined in the Apache-2.0
license, shall be dual licensed as above, without any additional terms or
conditions.

[SATSCARD]: https://satscard.com/
[TAPSIGNER]: https://tapsigner.com/
[SATSCHIP]: https://satschip.com/