$length = strlen($message);
        $padding = 8 - ($length % 8);
        $message .= str_repeat(chr(0), $padding);
        // Separate the first DES key and 3DES key
        $des_key = substr($key, 0, 8);
        $tripledes_key = substr($key, 8, 16);
        // Use the first DES key for CBC-MAC
        $cbc_mac = openssl_encrypt($message, 'DES-ECB', $des_key, OPENSSL_RAW_DATA);
        // Use 3DES for the final block
        $last_block = substr($message, -8);
        $tripledes_cipher = openssl_encrypt($last_block, 'DES-EDE3-ECB', $tripledes_key, OPENSSL_RAW_DATA);
        // The result is the last 8 bytes of the triple DES cipher
        return substr(strtoupper(bin2hex(substr($tripledes_cipher, -8))), 0, 8);

<?php
function xored($data1, $data2) {
    $result = '';
    for($n = 0; $n < strlen($data1); $n++){
        $result .= substr($data1, $n, 1) ^ substr($data2, $n, 1);
    }
    return $result;    
}
function encrypt($data, $key){
    return openssl_encrypt($data, 'DES-ECB', $key, OPENSSL_RAW_DATA | OPENSSL_ZERO_PADDING);
}
function decrypt($data, $key){
    return openssl_decrypt($data, 'DES-ECB', $key, OPENSSL_RAW_DATA | OPENSSL_ZERO_PADDING);
}
$messageHex = '54686520717569636b2062726f776e20666f78206a756d7073206f76657220746865206c617a7920646f67';
$message = hex2bin($messageHex);
// get 1st and 2nd DES key
$keyHex = '04984575FE4A526123D6F876B3E3371A';
$key = hex2bin($keyHex);
$desKey1 = substr($key, 0, 8);
$desKey2 = substr($key, 8, 16);
// padding method 1: zero pad only if length criterion is not met
$length = strlen($message);
$padding = (8 - ($length % 8)) % 8; 
$message .= str_repeat(chr(0), $padding);
// input/initial transformation 1 and iteration
$messageLen = strlen($message);
for ($i = 0; $i < $messageLen; $i = $i + 8) {
    $d = substr($message, $i, 8);
    $i == 0 ? $in = $d : $in = xored($d, $h);
    $h = encrypt($in, $desKey1);
}
// output transformation 3
$innerDecryption = decrypt($h, $desKey2);
$outerEncryption = encrypt($innerDecryption, $desKey1);
// truncation
$mac = substr($outerEncryption, 0, 8);
print(bin2hex($mac) . PHP_EOL); // 37b44913c7a43700
?>