Introduction
BLAKE2b is a cryptographic hash function defined in RFC 7693 that is faster than MD5 and SHA-1 while offering security comparable to SHA-3. It produces variable-length digests up to 64 bytes (512 bits). This tool generates BLAKE2b hashes entirely in your browser, with no data sent to any server. Adjust the output length slider to produce digests from 1 to 64 bytes.
What this tool does
- Generates BLAKE2b hashes from any text input in real time as you type.
- Supports configurable output length from 1 to 64 bytes (2 to 128 hex characters).
- Implements the full BLAKE2b algorithm per RFC 7693 using 32-bit pair arithmetic for ES2017 compatibility.
- Displays the hash as a lowercase hexadecimal string.
- Processes all data locally in your browser with no network requests.
How this tool works
Type or paste text into the input field. The tool converts the text to UTF-8 bytes and feeds them through the BLAKE2b compression function. The output length slider controls how many bytes of digest are produced (1-64). The hash updates instantly as you change the input or output length. All computation happens client-side using a pure JavaScript implementation that uses 32-bit integer pairs to emulate 64-bit operations, ensuring compatibility with older JavaScript engines that lack BigInt support.
How BLAKE2b works
BLAKE2 was designed by Jean-Philippe Aumasson, Samuel Neves, Zooko Wilcox-O'Hairn, and Christian Winnerlein and published in 2012. It was standardized as RFC 7693 in 2015. BLAKE2b is the 64-bit variant optimized for 64-bit platforms, producing digests up to 512 bits. The algorithm uses a HAIFA construction with a compression function based on the ChaCha round function. It processes 128-byte blocks and uses 12 rounds per block. Unlike SHA-2, BLAKE2b does not require padding beyond the final block. The key advantage of BLAKE2b is its speed: on modern CPUs it is faster than MD5 while being cryptographically secure. It is used in Argon2 (the password hashing competition winner), the WireGuard VPN protocol, and numerous software projects including Python's hashlib, GNU coreutils, and the IPFS project.
How to use this tool
- Enter the text you want to hash in the input field.
- Adjust the output length slider to select the desired digest size (1-64 bytes).
- The BLAKE2b hash appears instantly in the output field as a hex string.
- Use the Copy button to copy the hash to your clipboard.
- Change the input or length at any time and the hash updates automatically.
Real-world examples
Hashing a simple string
Input: `hello` with output length 64 bytes. Output: `e9c470f9...` (128 hex characters). The same input always produces the same output.
Short digest for checksums
Input: `hello` with output length 4 bytes. Output: `6b8814e2` (8 hex characters). Shorter digests are useful for compact checksums where collision resistance requirements are lower.
Empty input
Input: empty string with output length 64 bytes. BLAKE2b still produces a valid 512-bit hash for empty input, as the algorithm processes zero-length messages correctly.
Comparison with similar methods
| Method | Complexity | Typical use |
|---|---|---|
| BLAKE2b | O(n) — 12 rounds per 128-byte block | Fast hashing, Argon2, WireGuard, file integrity |
| SHA-256 | O(n) — 64 rounds per 64-byte block | Digital signatures, TLS, blockchain |
| MD5 | O(n) — 4 rounds per 64-byte block | Legacy checksums (broken, do not use for security) |
| SHA-3 | O(n) — sponge construction | NIST standard, post-quantum readiness |
Limitations or considerations
BLAKE2b is not a password hashing function. For password storage, use Argon2, bcrypt, or PBKDF2, which incorporate salting and work factors. The implementation uses 32-bit pair arithmetic to emulate 64-bit operations for ES2017 compatibility, which is slower than native 64-bit implementations. Hash output longer than 64 bytes is not supported by the BLAKE2b specification. This tool does not support keyed hashing (MAC mode) or tree mode.
Frequently asked questions
Is BLAKE2b secure?
Yes. BLAKE2b has no known practical attacks and is considered as secure as SHA-3. It is standardized in RFC 7693 and used in production systems including WireGuard and Argon2.
Why is BLAKE2b faster than SHA-256?
BLAKE2b processes 128-byte blocks with 12 rounds, while SHA-256 processes 64-byte blocks with 64 rounds. The larger block size and fewer rounds give BLAKE2b a significant speed advantage on 64-bit platforms.
Can I use BLAKE2b for password hashing?
No. BLAKE2b is a plain hash function without salting or work factors. Use Argon2 (which is built on BLAKE2b), bcrypt, or PBKDF2 for password storage.
What is the difference between BLAKE2b and BLAKE2s?
BLAKE2b is the 64-bit variant producing up to 64-byte digests, optimized for 64-bit platforms. BLAKE2s is the 32-bit variant producing up to 32-byte digests, optimized for 8- to 32-bit platforms.
Conclusion
The BLAKE2b hash generator provides a fast, secure, RFC 7693-compliant hashing tool that runs entirely in your browser. With configurable output length and real-time hashing, it is ideal for file integrity checks, content addressing, and cryptographic applications where speed matters. For password hashing, use the Argon2 or PBKDF2 tools on this site instead.