why AES java decryption return extra characters?
<p>Excuse me for bad English.
i use mcrypt which i get it from here <a href="https://snipt.net/raw/ee573b6957b7416f28aa560ead71c3a2/?nice" rel="nofollow noreferrer">MCrypt for php and java</a>. in my android application i need php and java communicate securely so i get above mentioned AES.
the problem is when php sends encrypted data, java can decrypt it but some extra characters are included.</p>

<p>JAVA Code</p>

<pre><code>    import java.security.NoSuchAlgorithmException;

    import javax.crypto.Cipher;
    import javax.crypto.NoSuchPaddingException;
    import javax.crypto.spec.IvParameterSpec;
    import javax.crypto.spec.SecretKeySpec;

    public class MCrypt {

            private String iv = "fedcba9876543210";//Dummy iv (CHANGE IT!)
            private IvParameterSpec ivspec;
            private SecretKeySpec keyspec;
            private Cipher cipher;

            private String SecretKey = "0123456789abcdef";//Dummy secretKey (CHANGE IT!)

            public MCrypt()
            {
                    ivspec = new IvParameterSpec(iv.getBytes());

                    keyspec = new SecretKeySpec(SecretKey.getBytes(), "AES");

                    try {
                            cipher = Cipher.getInstance("AES/CBC/NoPadding");
                    } catch (NoSuchAlgorithmException e) {
                            // TODO Auto-generated catch block
                            e.printStackTrace();
                    } catch (NoSuchPaddingException e) {
                            // TODO Auto-generated catch block
                            e.printStackTrace();
                    }
            }

            public byte[] encrypt(String text) throws Exception
            {
                    if(text == null || text.length() == 0)
                            throw new Exception("Empty string");

                    byte[] encrypted = null;

                    try {
                            cipher.init(Cipher.ENCRYPT_MODE, keyspec, ivspec);

                            encrypted = cipher.doFinal(padString(text).getBytes());
                    } catch (Exception e)
                    {                       
                            throw new Exception("[encrypt] " + e.getMessage());
                    }

                    return encrypted;
            }

            public byte[] decrypt(String code) throws Exception
            {
                    if(code == null || code.length() == 0)
                            throw new Exception("Empty string");

                    byte[] decrypted = null;

                    try {
                            cipher.init(Cipher.DECRYPT_MODE, keyspec, ivspec);

                            decrypted = cipher.doFinal(hexToBytes(code));
                    } catch (Exception e)
                    {
                            throw new Exception("[decrypt] " + e.getMessage());
                    }
                    return decrypted;
            }



            public static String bytesToHex(byte[] data)
            {
                    if (data==null)
                    {
                            return null;
                    }

                    int len = data.length;
                    String str = "";
                    for (int i=0; i&lt;len; i++) {
                            if ((data[i]&amp;0xFF)&lt;16)
                                    str = str + "0" + java.lang.Integer.toHexString(data[i]&amp;0xFF);
                            else
                                    str = str + java.lang.Integer.toHexString(data[i]&amp;0xFF);
                    }
                    return str;
            }


            public static byte[] hexToBytes(String str) {
                    if (str==null) {
                            return null;
                    } else if (str.length() &lt; 2) {
                            return null;
                    } else {
                            int len = str.length() / 2;
                            byte[] buffer = new byte[len];
                            for (int i=0; i&lt;len; i++) {
                                    buffer[i] = (byte) Integer.parseInt(str.substring(i*2,i*2+2),16);
                            }
                            return buffer;
                    }
            }



            private static String padString(String source)
            {
              char paddingChar = ' ';
              int size = 16;
              int x = source.length() % size;
              int padLength = size - x;

              for (int i = 0; i &lt; padLength; i++)
              {
                      source += paddingChar;
              }

              return source;
            }
    }
</code></pre>

<p>the PHP code </p>

<pre><code> &lt;?php 

    class MCrypt
    {
            private $iv = 'fedcba9876543210'; #Same as in JAVA
            private $key = '0123456789abcdef'; #Same as in JAVA


            function __construct()
            {
            }

            function encrypt($str) {

              //$key = $this-&gt;hex2bin($key);    
              $iv = $this-&gt;iv;

              $td = mcrypt_module_open('rijndael-128', '', 'cbc', $iv);

              mcrypt_generic_init($td, $this-&gt;key, $iv);
              $encrypted = mcrypt_generic($td, $str);

              mcrypt_generic_deinit($td);
              mcrypt_module_close($td);

              return bin2hex($encrypted);
            }

            function decrypt($code) {
              //$key = $this-&gt;hex2bin($key);
              $code = $this-&gt;hex2bin($code);
              $iv = $this-&gt;iv;

              $td = mcrypt_module_open('rijndael-128', '', 'cbc', $iv);

              mcrypt_generic_init($td, $this-&gt;key, $iv);
              $decrypted = mdecrypt_generic($td, $code);

              mcrypt_generic_deinit($td);
              mcrypt_module_close($td);

              return utf8_encode(trim($decrypted));
            }

            protected function hex2bin($hexdata) {
              $bindata = '';

              for ($i = 0; $i &lt; strlen($hexdata); $i += 2) {
                    $bindata .= chr(hexdec(substr($hexdata, $i, 2)));
              }

              return $bindata;
            }

    }
</code></pre>

<p>so the scenario is java send data (simple text) in JSON format to PHP , php extract the data , encrypt it and finally echo it in JSON format</p>

<p>PHP call:</p>

<pre><code>&lt;?php

$data =json_decode(file_get_contents('php://input'), true);

$data=$data["request"];
require_once "encryption.php";
$etool=new MCrypt();
$data=$etool-&gt;encrypt($data);
$array=array('data'=&gt;$data);
echo json_encode($array);
</code></pre>

<p>JAVA code:</p>

<pre><code> //sb is StringBuilder
JSONObject j=new JSONObject(sb.toString());
encryption etool=new encryption();
result=j.get("data").toString();
result= new String(etool.decrypt( result ));
Log.d("success remote ",result );
</code></pre>

<p>the result is:</p>

<p>example������</p>

<p>and if i use Farsi/Arabic word it get worse</p>

<p>like this-> درود����������������</p>

<p>in addition, i checked other questions but i could not get the answer.</p>

<p><a href="https://stackoverflow.com/questions/29029410/aes-encryption-got-extra-trash-characters-in-decrypted-file">AES encryption, got extra trash characters in decrypted file</a> and<br>
<a href="https://stackoverflow.com/questions/16895540/php-mcrypt-encrypt-decrypt-returns-invisible-strange-characters">PHP MCRYPT encrypt/decrypt returns invisible strange characters?</a></p>

<p>thank you in advance!</p>