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diff --git a/third_party/rust/digest/README.md b/third_party/rust/digest/README.md new file mode 100644 index 0000000000..9f68559cd2 --- /dev/null +++ b/third_party/rust/digest/README.md @@ -0,0 +1,164 @@ +# RustCrypto: Digest Algorithm Traits + +[![crate][crate-image]][crate-link] +[![Docs][docs-image]][docs-link] +![Apache2/MIT licensed][license-image] +![Rust Version][rustc-image] +[![Project Chat][chat-image]][chat-link] +[![Build Status][build-image]][build-link] + +Traits which describe functionality of [cryptographic hash functions][0], a.k.a. +digest algorithms. + +See [RustCrypto/hashes][1] for implementations which use this trait. + +[Documentation][docs-link] + +## Minimum Supported Rust Version + +Rust **1.41** or higher. + +Minimum supported Rust version can be changed in the future, but it will be +done with a minor version bump. + +## SemVer Policy + +- All on-by-default features of this library are covered by SemVer +- MSRV is considered exempt from SemVer as noted above + +## Usage + +Let us demonstrate how to use crates in this repository using Sha256 as an +example. + +First add the `sha2` crate to your `Cargo.toml`: + +```toml +[dependencies] +sha2 = "0.10" +``` + +`sha2` 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: + +```rust +use sha2::{Sha256, Digest}; + +let mut hasher = Sha256::new(); +let data = b"Hello world!"; +hasher.update(data); +// `input` can be called repeatedly and is generic over `AsRef<[u8]>` +hasher.update("String data"); +// Note that calling `finalize()` consumes hasher +let hash = hasher.finalize(); +println!("Result: {:x}", hash); +``` + +In this example `hash` has type [`GenericArray<u8, U64>`][2], which is a generic +alternative to `[u8; 64]`. + +Alternatively you can use chained approach, which is equivalent to the previous +example: + +```rust +let hash = Sha256::new() + .chain_update(b"Hello world!") + .chain_update("String data") + .finalize(); + +println!("Result: {:x}", hash); +``` + +If the whole message is available you also can use convenience `digest` method: + +```rust +let hash = Sha256::digest(b"my message"); +println!("Result: {:x}", hash); +``` + +### Hashing `Read`-able objects + +If you want to hash data from [`Read`][3] trait (e.g. from file) you can rely on +implementation of [`Write`][4] trait (requires enabled-by-default `std` feature): + +```rust +use sha2::{Sha256, Digest}; +use std::{fs, io}; + +let mut file = fs::File::open(&path)?; +let mut hasher = Sha256::new(); +let n = io::copy(&mut file, &mut hasher)?; +let hash = hasher.finalize(); + +println!("Path: {}", path); +println!("Bytes processed: {}", n); +println!("Hash value: {:x}", hash); +``` + +### Generic code + +You can write generic code over `Digest` (or other traits from `digest` crate) +trait which will work over different hash functions: + +```rust +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.update(password.as_bytes()); + hasher.update(b"$"); + hasher.update(salt.as_bytes()); + output.copy_from_slice(hasher.finalize().as_slice()) +} + +let mut buf1 = [0u8; 32]; +let mut buf2 = [0u8; 64]; + +hash_password::<sha2::Sha256>("my_password", "abcd", &mut buf1); +hash_password::<sha2::Sha512>("my_password", "abcd", &mut buf2); +``` + +If you want to use hash functions with trait objects, use `digest::DynDigest` +trait. + +## 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/digest.svg +[crate-link]: https://crates.io/crates/digest +[docs-image]: https://docs.rs/digest/badge.svg +[docs-link]: https://docs.rs/digest/ +[license-image]: https://img.shields.io/badge/license-Apache2.0/MIT-blue.svg +[rustc-image]: https://img.shields.io/badge/rustc-1.41+-blue.svg +[chat-image]: https://img.shields.io/badge/zulip-join_chat-blue.svg +[chat-link]: https://rustcrypto.zulipchat.com/#narrow/stream/260041-hashes +[build-image]: https://github.com/RustCrypto/traits/workflows/digest/badge.svg?branch=master&event=push +[build-link]: https://github.com/RustCrypto/traits/actions?query=workflow%3Adigest + +[//]: # (general links) + +[0]: https://en.wikipedia.org/wiki/Cryptographic_hash_function +[1]: https://github.com/RustCrypto/hashes +[2]: https://docs.rs/generic-array +[3]: https://doc.rust-lang.org/std/io/trait.Read.html +[4]: https://doc.rust-lang.org/std/io/trait.Write.html +[5]: https://en.wikipedia.org/wiki/Hash-based_message_authentication_code +[6]: https://github.com/RustCrypto/MACs |