When set to TRUE, outputs raw binary data.
Default value (FALSE) outputs lowercase hexits.
Return Values
Returns a string containing the calculated message digest as lowercase hexits
unless raw_output is set to true in which case the raw
binary representation of the message digest is returned.
Examples
Example 1. hash_final() example
<?php
$ctx = hash_init('sha1');
hash_update($ctx, 'The quick brown fox jumped over the lazy dog.');
echo hash_final($ctx);
?>