getrandom

A Rust library for retrieving random data from (operating) system source. It is assumed that system always provides high-quality cryptographically secure random data, ideally backed by hardware entropy sources. This crate derives its name from Linux‘s getrandom function, but is cross platform, roughly supporting the same set of platforms as Rust’s std lib.

This is a low-level API. Most users should prefer using high-level random-number library like rand.

Usage

Add this to your Cargo.toml:

[dependencies]
getrandom = "0.1"

Then invoke the getrandom function:

fn get_random_buf() -> Result<[u8; 32], getrandom::Error> {
    let mut buf = [0u8; 32];
    getrandom::getrandom(&mut buf)?;
    Ok(buf)
}

Features

This library is no_std for every supported target. However, getting randomness usually requires calling some external system API. This means most platforms will require linking against system libraries (i.e. libc for Unix, Advapi32.dll for Windows, Security framework on iOS, etc...).

The log library is supported as an optional dependency. If enabled, error reporting will be improved on some platforms.

For the wasm32-unknown-unknown target, one of the following features should be enabled:

By default, compiling getrandom for an unsupported target will result in a compilation error. If you want to build an application which uses getrandom for such target, you can either:

Use [replace] or [patch] section in your Cargo.toml to switch to a custom implementation with a support of your target.
Enable the dummy feature to have getrandom use an implementation that always fails at run-time on unsupported targets.

Minimum Supported Rust Version

This crate requires Rust 1.32.0 or later.

License

The getrandom library is distributed under either of

at your option.