# RustCrypto: Concat KDF

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Pure Rust implementation of the Concatenation Key Derivation Function (Concat KDF) generic over hash function. 
This function is described in the section 5.8.1 of [NIST SP 800-56A, Recommendation for Pair-Wise Key Establishment
Schemes Using Discrete Logarithm Cryptography](https://nvlpubs.nist.gov/nistpubs/Legacy/SP/nistspecialpublication800-56ar.pdf).

# Usage

The most common way to use Concat KDF is as follows: you generate a shared secret with other party (e.g. via Diffie-Hellman algorithm) 
and use key derivation function to derive a shared key.

```rust
let mut key = [0u8; 32];
concat_kdf::derive_key_into::<sha2::Sha256>(b"shared-secret", b"other-info", &mut key).unwrap();
```

[crate-image]: https://img.shields.io/crates/v/concat-kdf.svg
[crate-link]: https://crates.io/crates/concat-kdf
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[docs-link]: https://docs.rs/concat-kdf/
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[build-link]: https://github.com/RustCrypto/KDFs/actions?query=workflow:concat-kdf