README.md

RustCrypto: hashes

Collection of cryptographic hash functions written in pure Rust.

All algorithms reside in the separate crates and implemented using traits from digest crate. Additionally all crates do not require the standard library (i.e. no_std capable) and can be easily used for bare-metal or WebAssembly programming.

Supported algorithms

Note: For new applications, or where compatibility with other existing standards is not a primary concern, we strongly recommend to use either BLAKE2, SHA-2 or SHA-3.

Name	Alt name	Crates.io	Documentation	Security Level
BLAKE2				💚
GOST94	GOST R 34.11-94			💛
Grøstl	Groestl			💚
MD2				💔
MD4				💔
MD5 ❗				💔
RIPEMD-160				💚
RIPEMD-320				💚*
SHA-1 ❗				💔
SHA-2				💚
SHA-3	Keccak			💚
Streebog	GOST R 34.11-2012			💛
Whirlpool				💚

* RIPEMD-320 provides only the same security as RIPEMD-160

Security Level Legend

The following describes the security level ratings associated with each hash function (i.e. algorithms, not the specific implementation):

Heart	Description
💚	No known successful attacks
💛	Theoretical break: security lower than claimed
💔	Attack demonstrated in practice: avoid if at all possible

Minimum Supported Rust Version (MSRV)

All crates in this repository support Rust 1.21 or higher. In future minimally supported version of Rust can be changed, but it will be done with a minor version bump.

Crate names

Whenever possible crates are published under the the same name as the crate folder. Owners of md5 and sha1 crates declined (1, 2) to participate in this project. This is why crates marked by ❗ are published under md-5 and sha-1 names respectively.

Usage

Let us demonstrate how to use crates in this repository using BLAKE2b as an example.

First add blake2 crate to your Cargo.toml:

[dependencies]
blake2 = "0.8"

blake2 and other crates re-export digest crate and Digest trait for convenience, so you don't have to add digest crate as an explicit dependency.

Now you can write the following code:

use blake2::{Blake2b, Digest};

let mut hasher = Blake2b::new();
let data = b"Hello world!";
hasher.input(data);
// `input` can be called repeatedly and is generic over `AsRef<[u8]>`
hasher.input("String data");
// Note that calling `result()` consumes hasher
let hash = hasher.result();
println!("Result: {:x}", hash);

In this example hash has type GenericArray<u8, U64>, which is a generic alternative to [u8; 64].

Alternatively you can use chained approach, which is equivalent to the previous example:

let hash = Blake2b::new()
    .chain(b"Hello world!")
    .chain("String data")
    .result();
println!("Result: {:x}", hash);

If the whole message is available you also can use convinience digest method:

let hash = Blake2b::digest(b"my message");
println!("Result: {:x}", hash);

Hashing Readable objects

If you want to hash data from Read trait (e.g. from file) you can rely on implementation of Write trait (requires enabled-by-default std feature):

use blake2::{Blake2b, Digest};
use std::{fs, io};

let mut file = fs::File::open(&path)?;
let mut hasher = Blake2b::new();
let n = io::copy(&mut file, &mut hasher)?;
let hash = hasher.result();
println!("Path: {}", path);
println!("Bytes processed: {}", n);
println!("Hash value: {:x}", hash);

Hash-based Message Authentication Code (HMAC)

If you want to calculate Hash-based Message Authentication Code (HMAC), you can use generic implementation from hmac crate, which is a part of the RustCrypto/MACs repository.

Generic code

You can write generic code over Digest (or other traits from digest crate) trait which will work over different hash functions:

use digest::Digest;

// Toy example, do not use it in practice!
// Instead use crates from: https://github.com/RustCrypto/password-hashing
fn hash_password<D: Digest>(password: &str, salt: &str, output: &mut [u8]) {
    let mut hasher = D::new();
    hasher.input(password.as_bytes());
    hasher.input(b"$");
    hasher.input(salt.as_bytes());
    output.copy_from_slice(hasher.result().as_slice())
}

use blake2::Blake2b;
use sha2::Sha256;

hash_password::<Blake2b>("my_password", "abcd", &mut buf);
hash_password::<Sha256>("my_password", "abcd", &mut buf);

If you want to use hash functions with trait objects, use digest::DynDigest trait.

License

All crates licensed under either of

• Apache License, Version 2.0
• MIT license

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.