BLAKE3 is a cryptographic hash function built on BLAKE, one of the finalists in the competition that picked SHA-3. The RFC says it's about as secure as SHA3-256 but much faster. This RFC from Hans Henrik Bergan adds BLAKE3 to PHP's hash extension.

Why add it

Speed is the main reason. In PHP's own hash benchmark on an AMD Ryzen 9 7950x, BLAKE3 was over four times faster than SHA3-256, finishing in 0.007752 seconds compared to 0.031518 seconds.

Show me

You'd use it with the functions you already know. Here is the RFC's example:

$hash = hash('blake3', 'The quick brown fox jumps over the lazy dog');
echo $hash, PHP_EOL; // 2f1514181aadccd913abd94cfa592701a5686ab23f8df1dff1b74710febc6d4a

$key = 'secret-key';
$hash_keyed = hash_hmac('blake3', 'The quick brown fox jumps over the lazy dog', $key);

The RFC covers:

  • blake3 as a new algorithm for hash()
  • Keyed hashing with hash_hmac()
  • New ext/hash documentation with BLAKE3 examples

There are no new constants and no new php.ini settings.

What's left for later

BLAKE3 can spread work across several CPU threads and can produce output of any length. PHP's hash functions don't support either today, so the RFC leaves both for future work.

What it means for existing code

Nothing breaks. This only adds a new algorithm, and the other hash algorithms work the same as before.

Where it stands

The RFC has been a draft since January 24, 2025, and targets the next PHP 8.x release. The page has a yes or no vote set up, but no one has voted. The code is in php-src PR #13194.