Saturday, February 11, 2012

How to Encrypt / Decrypt Between Android and PHP?

How to use it in Java..
mcrypt = new MCrypt();
/* Encrypt */
String encrypted = MCrypt.bytesToHex( mcrypt.encrypt("Text to Encrypt") );
/* Decrypt */
String decrypted = new String( mcrypt.decrypt( encrypted ) );
How to use it in php...

$mcrypt = new MCrypt();
#Encrypt
$encrypted = $mcrypt->encrypt("Text to encrypt");
#Decrypt
$decrypted = $mcrypt->decrypt($encrypted);

/***********/

/**JAVA**/


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<len; i++) {
if ((data[i]&0xFF)<16)
str = str + "0" + java.lang.Integer.toHexString(data[i]&0xFF);
else
str = str + java.lang.Integer.toHexString(data[i]&0xFF);
}
return str;
}


public static byte[] hexToBytes(String str) {
if (str==null) {
return null;
} else if (str.length() < 2) {
return null;
} else {
int len = str.length() / 2;
byte[] buffer = new byte[len];
for (int i=0; i<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 < padLength; i++)
 {
 source += paddingChar;
 }


 return source;
}
}






====================================================


/**********/
/**PHP**/


<?php 


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




function __construct()
{
}


function encrypt($str) {


 //$key = $this->hex2bin($key);    
 $iv = $this->iv;


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


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


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


 return bin2hex($encrypted);
}


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


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


 mcrypt_generic_init($td, $this->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; $i < strlen($hexdata); $i += 2) {
$bindata .= chr(hexdec(substr($hexdata, $i, 2)));
 }


 return $bindata;
}


}

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