Crate blake3

Expand description

The official Rust implementation of the BLAKE3 cryptographic hash function.

Examples

// Hash an input all at once.
let hash1 = blake3::hash(b"foobarbaz");

// Hash an input incrementally.
let mut hasher = blake3::Hasher::new();
hasher.update(b"foo");
hasher.update(b"bar");
hasher.update(b"baz");
let hash2 = hasher.finalize();
assert_eq!(hash1, hash2);

// Extended output. OutputReader also implements Read and Seek.
let mut output = [0; 1000];
let mut output_reader = hasher.finalize_xof();
output_reader.fill(&mut output);
assert_eq!(&output[..32], hash1.as_bytes());

// Print a hash as hex.
println!("{}", hash1);

The std feature (the only feature enabled by default) is required for implementations of the Write and Seek traits, and also for runtime CPU feature detection. If this feature is disabled, the only way to use the SIMD implementations in this crate is to enable the corresponding instruction sets globally, with e.g. RUSTFLAGS="-C target-cpu=native". The resulting binary will not be portable to other machines.

The rayon feature (disabled by default, but enabled for docs.rs) adds the Hasher::update_rayon method, for multithreaded hashing. However, even if this feature is enabled, all other APIs remain single-threaded.

The neon feature enables ARM NEON support. Currently there is no runtime CPU feature detection for NEON, so you must only enable this feature for targets that are known to have NEON support. In particular, some ARMv7 targets support NEON, and some don’t.

The traits-preview feature enables implementations of traits from the RustCrypto digest and crypto-mac crates, and re-exports those crates as traits::digest and traits::crypto_mac. However, the traits aren’t stable, and they’re expected to change in incompatible ways before those crates reach 1.0. For that reason, this crate makes no SemVer guarantees for this feature, and callers who use it should expect breaking changes between patch versions. (The “-preview” feature name follows the conventions of the RustCrypto signature crate.)