# RustCrypto: `sm4` block cipher
[![crate][crate-image]][crate-link]
[![Docs][docs-image]][docs-link]
![Apache2/MIT licensed][license-image]
[Documentation][docs-link]
## Warnings
This is an experimental pure Rust implementation of the Serpent block cipher.
It has never received any review by professional cryptographers.
We recommend it should not be used in production applications.
**USE AT YOUR OWN RISK.**
## License
Licensed under either of
* [Apache License, Version 2.0](http://www.apache.org/licenses/LICENSE-2.0)
* [MIT license](http://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.
[//]: # (badges)
[crate-image]: https://img.shields.io/crates/v/serpent.svg
[crate-link]: https://crates.io/crates/serpent
[docs-image]: https://docs.rs/serpent/badge.svg
[docs-link]: https://docs.rs/serpent/
[license-image]: https://img.shields.io/badge/license-Apache2.0/MIT-blue.svg