#crypto #sha2 #hash #digest

no-std sha2

SHA-2 hash functions

15 releases

0.7.1 Apr 27, 2018
0.7.0 Nov 15, 2017
0.6.0 Jun 12, 2017
0.4.2 Jan 23, 2017
0.1.2 May 6, 2016

#15 in Cryptography

Download history 7192/week @ 2018-06-11 9357/week @ 2018-06-18 9209/week @ 2018-06-25 8884/week @ 2018-07-02 7190/week @ 2018-07-09 9607/week @ 2018-07-16 9905/week @ 2018-07-23 8445/week @ 2018-07-30 8695/week @ 2018-08-06 8625/week @ 2018-08-13 7634/week @ 2018-08-20 8750/week @ 2018-08-27 8822/week @ 2018-09-03

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Used in 433 crates (146 directly)


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RustCrypto hashes Build Status

Collection of cryptographic hash functions written in pure Rust.

All algorithms split into 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 programming.

Supported algorithms

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

Name Alt name Crates.io Documentation Security Level
BLAKE2 crates.io Documentation :green_heart:
GOST94 GOST R 34.11-94 crates.io Documentation :yellow_heart:
Grøstl Groestl crates.io Documentation :green_heart:
MD2 crates.io Documentation :broken_heart:
MD4 crates.io Documentation :broken_heart:
MD5 :exclamation: crates.io Documentation :broken_heart:
RIPEMD-160 crates.io Documentation :green_heart:
SHA-1 :exclamation: crates.io Documentation :broken_heart:
SHA-2 crates.io Documentation :green_heart:
SHA-3 Keccak crates.io Documentation :green_heart:
Streebog GOST R 34.11-2012 crates.io Documentation :yellow_heart:
Whirlpool crates.io Documentation :green_heart:

Security Level Legend

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

Heart Description
:green_heart: No known successful attacks
:yellow_heart: Theoretical break: security lower than claimed
:broken_heart: Attack demonstrated in practice: avoid if at all possible

Minimum Rust version

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 the minor version bump.

Older crate versions support older Rust as well up to 1.13.

Crate names

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


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

First add blake2 crate to your Cargo.toml:

blake2 = "0.7"

blake2 and other crates re-export 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!";
// `input` can be called repeatedly
hasher.input("String data".as_bytes());
// Note that calling `result()` consumes hasher
let hash = hasher.result();
println!("Result: {:x}", hash);

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

Also you can use the following approach if the whole message is available:

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 enable std feature in digest crate:

blake2 = "0.7"
digest = { version = "0.7", features = ["std"]}

And use digest_reader method which will compute hash by reading data using 1 KB blocks:

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

let mut file = fs::File::open(&path)?;
let hash = Blake2b::digest_reader(&mut file)?;
println!("{:x}\t{}", hash, path);

Hash-based Message Authentication Code (HMAC)

One of the common tasks for cryptographic hash functions is generation of Message Authentication Codes (MAC). In RustCrypto all MAC functions represented using Mac trait from crypto-mac crate. Some hash functions provide Mac implementations (e.g. BLAKE2), but for others you can use generically implemented HMAC from hmac crate.

To demonstrate how to use HMAC, lets use SHA256 as an example. First add the following dependencies to your crate:

hmac = "0.5"
sha2 = "0.7"

To get the authentication code:

extern crate hmac;
extern crate sha2;

use sha2::Sha256;
use hmac::{Hmac, Mac};

// Create `Mac` trait implementation, namely HMAC-SHA256
let mut mac = Hmac::<Sha256>::new(b"my secret and secure key").unwrap();
mac.input(b"input message");

// `result` has type `MacResult` which is a thin wrapper around array of
// bytes for providing constant time equality check
let result = mac.result();
// To get underlying array use `code` method, but be carefull, since
// incorrect use of the code value may permit timing attacks which defeat
// the security provided by the `MacResult`
let code_bytes = result.code();

To verify the message:

let mut mac = Hmac::<Sha256>::new(b"my secret and secure key").unwrap();

mac.input(b"input message");

// `verify` will return `Ok(())` if code is correct, `Err(MacError)` otherwise

Generic code

You can write generic code over Digest trait which will work over different hash functions:

use digest::Digest;

// Toy example, do not use it in practice!
fn hash_password<D: Digest>(password: &str, salt: &str, output: &mut [u8]) {
    let mut hasher = D::new();

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

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


All crates licensed under either of

at your option.


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.