What this BLAKE2b generator does
This tool computes the BLAKE2b hash of any text, with a digest length you choose from 1 to 64 bytes. BLAKE2b is a modern, high-speed cryptographic hash used in cryptocurrencies, password hashing (as the core of Argon2), file integrity, and content addressing. It was designed as a faster and simpler replacement for SHA-2 and SHA-3 that is still conservative enough to trust in security-critical contexts.
How BLAKE2b works internally
BLAKE2b (RFC 7693) is built on a ChaCha-derived compression function that processes 128-byte blocks using eight 64-bit state words plus eight 64-bit initialisation-vector words. The requested digest length is folded into the first IV word as a parameter block, so each output size is a distinct hash rather than a truncation. Each block is mixed with twelve rounds of the G function — additions, XORs, and right-rotations by 32, 24, 16, and 63 bits — over a message schedule defined by the SIGMA permutation table. A final block sets the last-block flag, and the low bytes of the eight state words form the digest. Everything here runs in browser JavaScript using BigInt for the 64-bit arithmetic.
Choosing a digest length
BLAKE2b’s variable-length output is a genuine feature, not just truncation. Because the length parameter is mixed into the initial state, a 32-byte BLAKE2b-256 hash is a completely independent function from 64-byte BLAKE2b-512 — not simply the first half of it. Common choices:
- 32 bytes (256 bits) — broadly compatible with SHA-256-sized slots; used in Ethereum and other crypto systems
- 48 bytes (384 bits) — matches SHA-384 size expectations
- 64 bytes (512 bits) — full strength; default in most BLAKE2b implementations
BLAKE2b vs other hashes
| Hash | Speed (relative) | Digest size | Security status |
|---|---|---|---|
| MD5 | Fast | 128-bit | Broken — collisions found |
| SHA-1 | Moderate | 160-bit | Broken — collisions found |
| SHA-256 | Moderate | 256-bit | Secure |
| BLAKE2b | Very fast | 8–512 bit | Secure |
| SHA-3-256 | Slower | 256-bit | Secure |
BLAKE2b is often faster than MD5 on 64-bit hardware while being cryptographically strong — its main design goal was to eliminate the excuse of choosing MD5 for performance reasons.
When to use BLAKE2b
- File integrity and checksums — when you want speed and security without worrying about MD5’s broken status
- Content addressing — systems like IPFS use multihash wrappers that include BLAKE2b
- Non-password key derivation — as input to a KDF; for passwords, use the full Argon2 algorithm (which uses keyed BLAKE2b internally)
- MACs — keyed BLAKE2b (not available in this unkeyed tool) replaces HMAC-SHA-2 in many modern systems
Reference values and practical notes
- BLAKE2b-512 of the empty string:
786a02f742015903c6c6fd852552d272912f4740e15847618a86e217f71f5419d25e1031afee585313896444934eb04b903a685b1448b755d56f701afe9be2ce - A single changed byte in the input changes the entire digest (avalanche effect) — use this to confirm any implementation is working correctly by checking these known values.
- This tool is unkeyed; keyed BLAKE2b, which acts as a MAC, requires providing a key as part of the parameter block — that variant is not covered here.