шифрование — Шифрование изображения в Php с использованием алгоритма AES

Я пытаюсь зашифровать изображение при загрузке с использованием AES 128 бит, но текст зашифрован и расшифрован, но я не понимаю, как зашифровать изображения перед загрузкой. Ниже приведен код для AES, который я использую:

Код:

<?php
/**
Aes encryption
*/
class AES {

const M_CBC = 'cbc';
const M_CFB = 'cfb';
const M_ECB = 'ecb';
const M_NOFB = 'nofb';
const M_OFB = 'ofb';
const M_STREAM = 'stream';

protected $key;
protected $cipher;
protected $data;
protected $mode;
protected $IV;
/**
*
* @param type $data
* @param type $key
* @param type $blockSize
* @param type $mode
*/
function __construct($data = null, $key = null, $blockSize = null, $mode = null) {
$this->setData($data);
$this->setKey($key);
$this->setBlockSize($blockSize);
$this->setMode($mode);
$this->setIV("");
}

/**
*
* @param type $data
*/
public function setData($data) {
$this->data = $data;
}

/**
*
* @param type $key
*/
public function setKey($key) {
$this->key = $key;
}

/**
*
* @param type $blockSize
*/
public function setBlockSize($blockSize) {
switch ($blockSize) {
case 128:
$this->cipher = MCRYPT_RIJNDAEL_128;
break;

case 192:
$this->cipher = MCRYPT_RIJNDAEL_192;
break;

case 256:
$this->cipher = MCRYPT_RIJNDAEL_256;
break;
}
}

/**
*
* @param type $mode
*/
public function setMode($mode) {
switch ($mode) {
case AES::M_CBC:
$this->mode = MCRYPT_MODE_CBC;
break;
case AES::M_CFB:
$this->mode = MCRYPT_MODE_CFB;
break;
case AES::M_ECB:
$this->mode = MCRYPT_MODE_ECB;
break;
case AES::M_NOFB:
$this->mode = MCRYPT_MODE_NOFB;
break;
case AES::M_OFB:
$this->mode = MCRYPT_MODE_OFB;
break;
case AES::M_STREAM:
$this->mode = MCRYPT_MODE_STREAM;
break;
default:
$this->mode = MCRYPT_MODE_ECB;
break;
}
}

/**
*
*
* @return boolean
*/
public function validateParams() {
if ($this->data != null &&
$this->key != null &&
$this->cipher != null) {
return true;
} else {
return FALSE;
}
}

public function setIV($IV) {
$this->IV = $IV;
}
protected function getIV() {
if ($this->IV == "") {
$this->IV = mcrypt_create_iv(mcrypt_get_iv_size($this->cipher, $this->mode), MCRYPT_RAND);
}
return $this->IV;
}

/**
* @return type
* @throws Exception
*/
public function encrypt() {

if ($this->validateParams()) {
return trim(base64_encode(
mcrypt_encrypt(
$this->cipher, $this->key, $this->data, $this->mode, $this->getIV())));
} else {
throw new Exception('Invlid params!');
}
}
/**
*
* @return type
* @throws Exception
*/
public function decrypt() {
if ($this->validateParams()) {
return trim(mcrypt_decrypt(
$this->cipher, $this->key, base64_decode($this->data), $this->mode, $this->getIV()));
} else {
throw new Exception('Invlid params!');
}
}

}
?>

<?php
include 'enc.php';if(isset($_POST['submit']))
{
$blockSize = 128;
$inputKey = "My text to encrypt";$allowedExts = array("jpg", "jpeg", "gif", "png", "mp3", "mp4", "wma");
$fileName = $_FILES['file']['name'];
$extension = substr($fileName, strrpos($fileName, '.') + 1); // getting the info about the image to get its extension

if(in_array($extension, $allowedExts))
{
if ($_FILES["file"]["error"] > 0)
{
echo "Return Code: " . $_FILES["file"]["error"] . "<br />";
}
else
{
$aes = new AES($_FILES["file"]["tmp_name"], $inputKey, $blockSize);
$enc = $aes->encrypt();
echo "Upload: " . $_FILES["file"]["name"] . "<br />";
echo "Type: " . $_FILES["file"]["type"] . "<br />";
echo "Size: " . ($_FILES["file"]["size"] / 1024) . " Kb<br />";
echo "Temp file: " . $_FILES["file"]["tmp_name"] . "<br />";

if (file_exists("upload/" . $_FILES["file"]["name"]))
{
echo $_FILES["file"]["name"] . " already exists. ";
}
else
{
move_uploaded_file($_FILES["file"]["tmp_name"],"upload/" . $enc."jpg");
echo "Stored in: " . "upload/" . $_FILES["file"]["name"];
}
}
}
else
{
echo "Invalid file";
}
}
?>
<form method="post"  enctype="multipart/form-data" >

<label for="file"><span>Filename:</span></label>

<input type="file" name="file" id="file" />

<br />
<input type="submit" name="submit" value="Submit" />
</form>