blakity

A tiny, portable BLAKE3, optimized for size and speed without needing SIMD

blakity is a #![no_std] BLAKE3 in a single file with no dependencies, derived from upstream's reference_impl. It targets small binaries, such as UEFI applications, while staying faster than the reference implementation and needing no SIMD or platform-specific code.

Usage

Add blakity to your Cargo.toml:

[dependencies]
blakity = "0.1.0"

The API is the same as upstream's reference_impl. finalize fills an output slice of any length, so it covers both the 32-byte hash and the extendable output:

let mut hasher = blakity::Hasher::new();
hasher.update(b"abc");
hasher.update(b"def");
let mut hash = [0; 32];
hasher.finalize(&mut hash);

Hasher::new_keyed(&[u8; 32]) gives the keyed hash and Hasher::new_derive_key(context) the key derivation function.

blakity has no SIMD and no multithreading, so for large inputs on a host with std, the official blake3 crate is much faster.

Comparison

Speed

Throughput in MB/s on an x86_64 host (fat LTO, opt-level = 3). Run with just bench and just bench-portable.

input	blakity	reference_impl	blake3 (portable)	blake3 (SIMD)	C (SIMD)
1 KiB	1,227	968	1,592	999	1,003
64 KiB	1,155	916	1,524	12,835	12,872
1024 KiB	1,153	913	1,524	12,857	13,071

Size

Bytes added to a no_std binary (code + data sections), measured against a baseline that doesn't hash. Built with bread's profile: opt-level = "z", the hash crate at opt-level = 3, fat LTO. Run with just size.

target	blakity	reference_impl	blake3 (`pure`)	blake3	C (portable)
x86_64-unknown-uefi+SSE2 (bread)	3,240	4,041	17,688	57,608	16,641
x86_64-unknown-uefi	3,392	4,461	9,852	58,460	15,681
aarch64-unknown-uefi	2,720	2,816	5,456	10,232	12,748
x86_64-unknown-none	3,358	4,304	12,229	58,582	15,663

Scope

blakity is developed alongside bread, an experimental UEFI bootloader for Linux, where it is tuned for an x86_64 UEFI target with SSE2.

License

Like upstream BLAKE3, at your option: CC0-1.0, Apache-2.0, or Apache-2.0 WITH LLVM-exception.

src/lib.rs is derived from the reference_impl of BLAKE3 by the BLAKE3 team, used under the same licenses.