Simple hashing function in PHP. Any alogrithm supported by the build in hash() function can be used. This function actually only adds rounds and concatenate the string with a salt.

hashStringFunction.php

<?php

/**
 * @param $string string The string/password to be hashed
 * @param $salt   string The salt that will be added to the string
 * @param $rounds int    Number of rounds
 * @param $algo   string The algorithm that should be used for hashing
 * @return string Returns the hashed string
 */
function createHash($string, $salt = '', $rounds = 500, $algo = 'sha256') {
    for ($rounds; $rounds > 0; $rounds--) {
		$string = hash($algo, $string . $salt);
	}
	return $string;
}