BLAKE2b Hasher
Compute BLAKE2b cryptographic hashes (RFC 7693).
Overview
The BLAKE2b hasher computes a fast modern cryptographic digest of any text or byte input. Paste a message, pick an output length, and receive a hex digest in a single keystroke. Optional keyed mode lets you use BLAKE2 as a built-in MAC without needing a separate HMAC construction.
It is the digest of choice when SHA-256 feels slow — popular in libsodium, WireGuard, Argon2 internals, and a growing number of file integrity tools. Engineers benchmarking hash performance, libsodium users debugging tag mismatches, and CTF players cracking BLAKE2 puzzles all want a BLAKE2b hash generator online.
How it works
BLAKE2b, defined in RFC 7693, is the 64-bit-word variant of BLAKE2 — itself a streamlined and tweaked version of the SHA-3 finalist BLAKE. It runs a fixed compression function based on the ChaCha permutation over 12 rounds, producing digests of any length from 1 to 64 bytes. Unlike SHA-2, the algorithm bakes in a personalisation field, a salt, and an optional key, so keyed BLAKE2 is a faster drop-in for HMAC-SHA-2 with provably equivalent security under standard assumptions. BLAKE2s is the 32-bit-word cousin tuned for 8- to 32-bit platforms; the two share design but produce different digests.
Examples
Input: abc
Output (512-bit BLAKE2b):
ba80a53f981c4d0d6a2797b69f12f6e94c212f14685ac4b74b12bb6fdbffa2d1
7d87c5392aab792dc252d5de4533cc9518d38aa8dbf1925ab92386edd4009923
Input: "" (empty)
Output (256-bit BLAKE2b-256):
0e5751c026e543b2e8ab2eb06099daa1d1e5df47778f7787faab45cdf12fe3a8
Input: "The quick brown fox jumps over the lazy dog"
Output (512-bit):
a8add4bdddfd93e4877d2746e62817b116364a1fa7bc148d95090bc7333b3673
f82401cf7aa2e4cb1ecd90296e3f14cb5413f8ed77be73045b13914cdcd6a918
FAQ
BLAKE2 or SHA-3?
BLAKE2 is generally 2–3× faster than SHA-256 in software and 3–4× faster than SHA-3-256, with comparable security guarantees. SHA-3 has a different internal design (Keccak sponge) and is the NIST standard, so pick it for FIPS-required contexts.
Is BLAKE2 collision-resistant?
Yes — to roughly 2^(n/2) work for an n-bit output. For a 256-bit BLAKE2b digest that is 2^128 operations, well beyond any feasible attack.
Why pick keyed BLAKE2 over HMAC-SHA-256?
Speed and simplicity. Keyed BLAKE2 is a single pass through the data and needs no inner/outer padding, so it is significantly faster than HMAC while remaining a secure MAC.
What output length should I pick?
256 bits (32 bytes) is the common default for fingerprints; 512 bits matches SHA-512. Shorter outputs are useful for short identifiers but cut into collision resistance.