Java vs PHP

gistfile1.java

import org.apache.commons.codec.digest.DigestUtils;
import org.apache.commons.codec.binary.Base64;

String sStringToDigest = InputString + "&" + sSecretString;
byte[] bMac = DigestUtils.md5 (sStringToDigest.getBytes()); 
String sMacEncoded = Base64.encodeBase64String (bMac);
sMacEncoded = sMacEncoded.substring (0,24);

gistfile2.php

$string_to_digest = $input_string . '&' . $secret_string;
$mac = hash('md5', $string_to_digest, true);
$mac_encoded = base64_encode($mac);
$mac_encoded = substr($mac_encoded, 0, 24);