(PHP Extension) Example: Hash Text in Chunks

Shows how to generate a final hash, like SHA-256, for a large text by processing it in chunks.

Chilkat PHP Downloads PHP Extension for Windows, Linux, MacOS, Alpine Linux

<?php

include("chilkat.php");

$crypt = new CkCrypt2();
$crypt->put_HashAlgorithm('sha256');
$crypt->put_Charset('utf-8');

$bd = new CkBinData();

$s = 'The quick brown fox jumped over the lazy dog.\r\n';

// Accumulate the text in a StringBuilder.  We'll demonstrate hashing the text in chunks,
// and then also hashing the entire text at once to show the results are the same.

$bd->AppendString($s,'utf-8');
$success = $crypt->HashBeginString($s);

$i = 0;
while ($i < 200) {
    $bd->AppendString($s,'utf-8');
    $crypt->HashMoreString($s);
    $i = $i + 1;
}

// Get the hash in base64 format.
$crypt->put_EncodingMode('base64');

$encodedHash = $crypt->hashFinalENC();
print 'Hash computed in chunks: ' . $encodedHash . "\n";

// Let's alternatively compute the hash of the entire amount of data at once,
// to show the hash computation is the same:
$encodedHash = $crypt->hashBdENC($bd);
print 'Hash computed in 1 step: ' . $encodedHash . "\n";

// Output:

// Hash computed in chunks: unwkVff61k40roRIJizaknreScHaL6frWe37kydXbZQ=
// Hash computed in 1 step: unwkVff61k40roRIJizaknreScHaL6frWe37kydXbZQ=

?>