# evpkdf

Rust implementation of OpenSSL [EVP_bytesToKey] function.

`evpkdf` derives key from the given password and salt.

Notice that this approach is **too weak** for modern standard
now. Newer applications should choice a more modern algorithm
like [bcrypt], [pbkdf2] or [scrypt].

[EVP_bytesToKey]: https://www.openssl.org/docs/man1.0.2/man3/EVP_BytesToKey.html
[bcrypt]: https://crates.io/crates/bcrypt
[pbkdf2]: https://crates.io/crates/pbkdf2
[scrypt]: https://crates.io/crates/scrypt

## Basic Usage

```rust
use evpkdf::evpkdf;
use hex_literal::hex;
use md5::Md5;   // from md-5 crate
use sha1::Sha1; // from sha-1 crate

let mut output = [];

evpkdf::<Md5>(b"password", b"saltsalt", 1000, &mut output);

assert_eq!(output, []);

let mut output = [0; 128 / 8];

evpkdf::<Md5>(b"password", b"saltsalt", 1000, &mut output);

assert_eq!(output, hex!("8006de5d2a5d15f9bbdb8f40196d5af1"));

let mut output = [0; 128 / 8];

evpkdf::<Sha1>(b"password", b"saltsalt", 1000, &mut output);

assert_eq!(output, hex!("f8833429b112582447bc66f433497f75"));
```

## Compatible with crypto-js

Below sinppet generates the same result as
`CryptoJS.kdf.OpenSSL.execute('password', 256 / 32, 128 / 32, 'saltsalt')`.

```rust
use evpkdf::evpkdf;
use hex_literal::hex;
use md5::Md5;   // from md-5 crate

const KEY_SIZE: usize = 256;
const IV_SIZE: usize = 128;

let mut output = [0; (KEY_SIZE + IV_SIZE) / 8];

evpkdf::<Md5>(b"password", b"saltsalt", 1, &mut output);

let (key, iv) = output.split_at(KEY_SIZE / 8);

assert_eq!(
    key,
    hex!("fdbdf3419fff98bdb0241390f62a9db35f4aba29d77566377997314ebfc709f2")
);

assert_eq!(
    iv,
    hex!("0b5ca7b1081f94b1ac12e3c8ba87d05a")
);
```

## License

MIT