<?php
$messages = [random_bytes(32), random_bytes(32), random_bytes(16)];
$state = sodium_crypto_generichash_init();
foreach ($messages as $message) {
sodium_crypto_generichash_update($state, $message);
}
$final = sodium_crypto_generichash_final($state);
var_dump(sodium_bin2hex($final));
$allAtOnce = sodium_crypto_generichash(implode('', $messages));
var_dump(sodium_bin2hex($allAtOnce));
?>
The above example will output
something similar to:
string(64) "e16e28bbbbcc39d9f5b1cbc33c41f1d217808640103e57a41f24870f79831e04"
string(64) "e16e28bbbbcc39d9f5b1cbc33c41f1d217808640103e57a41f24870f79831e04"