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why AES java decryption return extra characters?

Excuse me for bad English.
i use mcrypt which i get it from here MCrypt for php and java. 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.
JAVA 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<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;
}
}
the PHP code
<?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;
}
}
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
PHP call:
<?php
$data =json_decode(file_get_contents('php://input'), true);
$data=$data["request"];
require_once "encryption.php";
$etool=new MCrypt();
$data=$etool->encrypt($data);
$array=array('data'=>$data);
echo json_encode($array);
JAVA 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 );
the result is:
example������
and if i use Farsi/Arabic word it get worse
like this-> درود����������������
in addition, i checked other questions but i could not get the answer.
AES encryption, got extra trash characters in decrypted file and
PHP MCRYPT encrypt/decrypt returns invisible strange characters?
thank you in advance!

AES encrypt in blocks of 16 bytes. If your input ain't a multiple of 16 bytes, a padding scheme is needed. As you have not specified any padding option for Mcrypt, it uses "zero padding".
In your Java code you specify "NoPadding" when you instantiate your Cipher:
cipher = Cipher.getInstance("AES/CBC/NoPadding");
So Java considers the padding done by php to be part of the encrypted data.
You just need to ensure that your php and Java code uses the same padding scheme.

I think this is binary data which can not be displayed.
Have you tried to use base64 to convert it to a regular string before sending it to the php script?
In the php script then you do following to decode the base64 string.
$data=base64_decode($data["request"])

Java Aes class convert to php

Java code :
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;
import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;
public class AESSecurityUtil {
private static final String AES = "AES";
private static final String CHARSET_NAME = "utf-8";
private static SecretKeySpec getKey(String password) throws NoSuchAlgorithmException{
KeyGenerator kgen = KeyGenerator.getInstance(AES);
SecureRandom random=SecureRandom.getInstance("SHA1PRNG");
random.setSeed(password.getBytes());
kgen.init(128, random);
SecretKey secretKey = kgen.generateKey();
byte[] enCodeFormat = secretKey.getEncoded();
SecretKeySpec key = new SecretKeySpec(enCodeFormat, AES);
return key;
}
public static String encode(String str, String password)
{
byte[] arr = encodeToArr(str, password);
return byteArrToString(arr);
}
private static byte[] encodeToArr(String str, String password)
{
try
{
Cipher cipher = Cipher.getInstance(AES);
byte[] byteContent = str.getBytes(CHARSET_NAME);
cipher.init(Cipher.ENCRYPT_MODE, getKey(password));
byte[] result = cipher.doFinal(byteContent);
return result;
}
catch (Exception e)
{
e.printStackTrace();
}
return null;
}
public static String decode(String hexStr, String password){
byte[] arr = string2ByteArr(hexStr);
return decode(arr, password);
}
private static String decode(byte[] arr, String password) {
try{
Cipher cipher = Cipher.getInstance(AES);
cipher.init(Cipher.DECRYPT_MODE, getKey(password));
byte[] result = cipher.doFinal(arr);
return new String(result, CHARSET_NAME);
}catch (Exception e){
e.printStackTrace();
}
return null;
}
private static String byteArrToString(byte[] arr) {
StringBuffer sb = new StringBuffer();
for (int i = 0; i <arr.length; i++) {
String s = Integer.toString(arr[i] + 128, 16);
if (s.length() == 1){
s = "0" + s;
}
sb.append(s);
}
return sb.toString().toUpperCase();
}
private static byte[] string2ByteArr(String s) {
s = s.toUpperCase();
String str = "0123456789ABCDEF";
byte[] arr = new byte[s.length() / 2];
for (int i = 0; i <arr.length; i++){
char s1 = s.charAt(i * 2);
char s2 = s.charAt(i * 2 + 1);
int tmp1 = str.indexOf(s1) * 16;
int tmp2 = str.indexOf(s2);
arr[i] = (byte) (tmp1 + tmp2 - 128);
}
return arr;
}
public static void main(String[] args) throws Exception {
System.out.println(decode("03AB8A3B85AFDD3926850B14C1BFF608", "imcc"));
String keyStr = "UITN25LMUQC436IM";
String plainText = "this is a string will be AES_Encrypt";
String encText = encode(plainText,keyStr);
String decString = decode(encText,keyStr);
System.out.println(encText);
System.out.println(decString);
}
}
Does the class can turn into a php code to achieve encryption and decryption ? I think the problem is that the getKey method can not achieve in php.
This Java class, provided by the platform side, can not require making changes.
Please tell me where the problem is?
Thanks
Append ...my PHP code:
<?php
if (!function_exists('hex2bin')) {
function hex2bin($str) {
$sbin = "";
$len = strlen($str);
for ($i = 0; $i < $len; $i += 2) {
$sbin .= pack("H*", substr($str, $i, 2));
}
return $sbin;
}
}
class Util_AesEncrypt {
private $_cipher = MCRYPT_RIJNDAEL_128;
private $_mode = MCRYPT_MODE_ECB;
private function _pkcs5Pad($text, $blockSize) {
$pad = $blockSize - (strlen($text) % $blockSize);
return $text . str_repeat(chr($pad), $pad);
}
private function _pkcs5Unpad($text) {
$end = substr($text, -1);
$last = ord($end);
$len = strlen($text) - $last;
if (substr($text, $len) == str_repeat($end, $last)) {
return substr($text, 0, $len);
}
return false;
}
public function encrypt($encrypt, $key) {
$blockSize = mcrypt_get_block_size($this->_cipher, $this->_mode);
$paddedData = $this->_pkcs5Pad($encrypt, $blockSize);
$ivSize = mcrypt_get_iv_size($this->_cipher, $this->_mode);
$iv = mcrypt_create_iv($ivSize, MCRYPT_RAND);
$encrypted = mcrypt_encrypt($this->_cipher, $key, $paddedData, $this->_mode, $iv);
return bin2hex($encrypted);
}
public function decrypt($decrypt, $key) {
$decoded = hex2bin($decrypt);
$blockSize = mcrypt_get_iv_size($this->_cipher, $this->_mode);
$iv = mcrypt_create_iv($blockSize, MCRYPT_RAND);
$decrypted = mcrypt_decrypt($this->_cipher, $key, $decoded, $this->_mode, $iv);
return $this->_pkcs5Unpad($decrypted);
}
}
$keyStr = 'UITN25LMUQC436IM';
$plainText = 'this is a string will be AES_Encrypt';
$aes = new Util_AesEncrypt();
$encText = $aes->encrypt($plainText, $keyStr);
$decString = $aes->decrypt($encText, $keyStr);
echo $encText, "\n", $decString;
Different encryption results

The JAVA getKey() function will get 128bit key from password use SHA1PRNG, you can use this PHP code to get key from password:
$key = substr(openssl_digest(openssl_digest($password, 'sha1', true), 'sha1', true), 0, 16);
I also spent a lot of time in this case, Good Luck.

PHP + Android XML Encryption/Decryption

I have an app that is downloading and parsing an xml into an sql database. My problem is that the data from the xml once the app is deployed could easily be scraped and other people could use my hard earned data for their own evil purposes/apps. Basically I need to encrypt the xml using php, and then decrypt it using android. I've seen a couple of php classes that make it easy to encrypt but I'm not entirely sure what method to encrypt would be compatible with android.
Edit after solution:
At first I thought I had to ignore brackets for some reason and was going to iterate through all the text and spit out formatted xml lol. Much simpler than that.
$mcrypt = new MCrypt();
$datainxml = file_get_contents("data.xml");
$cipher = $mcrypt->encrypt($value);
echo $cipher;

The following code might help you. Using this you can encrypt/decrypt strings between PHP and Android.
Java Part:
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 Part:
<?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;
}
}
Usage (Java):
mcrypt = new MCrypt();
/* Encrypt */
String encrypted = MCrypt.bytesToHex( mcrypt.encrypt("Text to Encrypt") );
/* Decrypt */
String decrypted = new String( mcrypt.decrypt( encrypted ) );
Usage (PHP):
$mcrypt = new MCrypt();
#Encrypt
$encrypted = $mcrypt->encrypt("Text to encrypt");
#Decrypt
$decrypted = $mcrypt->decrypt($encrypted);

Encryption mismatch between Java and PHP

I'm working on an encryption system that passes the data to a 3rd party application. The encryption is done in Java and the decryption is done in PHP. Despite several attempts I can't get the encrypted string to be opened by the PHP application.
For testing purposes I created a PHP script that also encrypts the data, so I could compare the Java and PHP encrypted strings. The results match up to the 21st character, and then they differ. This is what I have:
// Java - Encrypt
private String EncryptAES(String text,String key) throws Exception
{
SecretKeySpec skeySpec = new SecretKeySpec(key.getBytes(), "AES");
// Instantiate the cipher
Cipher cipher = Cipher.getInstance("AES");
cipher.init(Cipher.ENCRYPT_MODE, skeySpec);
byte[] encrypted = cipher.doFinal(text.getBytes());
String encrypttext = new BASE64Encoder().encode(encrypted);
return encrypttext;
}
RESULT: TeUZAFxoFoQy/roPm5tXyPzJP/TLAwR1aIGn2xHbZpsbY1qrKwXfO+F/DAqmeTwB0b8e6dsSM+Yy0zrQt22E2Q==
and
// PHP - Encrypt
<?php
$encrypt = $crypt = openssl_encrypt($toCrypt,"AES256","key-32-char-long");
echo $encrypt;
?>
RESULT: TeUZAFxoFoQy/roPm5tXyC05wta1Z5YOXcq4OtgFoSbfVi/bHAuD6B5tDthT8EcGXQir08UAx0QvcqRJ2fJmbQ==
Obviously something is being done right because part of the strings match, but obviously not everything is correct because the rest does not match. Also, if I try to decrypt the Java string in PHP, nothing happens:
// PHP - Decrypt
<?php
$toDecrypt = "TeUZAFxoFoQy/roPm5tXyPzJP/TLAwR1aIGn2xHbZpsbY1qrKwXfO+F/DAqmeTwB0b8e6dsSM+Yy0zrQt22E2Q==";
$decrypt = openssl_decrypt($toDecrypt,"AES256","<key-32-char-long>");
echo $decrypt;
?>
RESULT: <nothing>
Does anyone have any ideas what might be happening?

Since both encrypted strings start with the same characters, it looks like you're using ECB in one and CBC in the other.

What about this (to decrypt within Your PHP):
$toDecrypt = "TeUZAFxoFoQy/roPm5tXyPzJP/TLAwR1aIGn2xHbZpsbY1qrKwXfO+F/DAqmeTwB0b8e6dsSM+Yy0zrQt22E2Q==";
$decrypt = openssl_decrypt(base64_decode($toDecrypt),"AES256","key-32-char-long");
echo $decrypt;
You should decrypt the base64 decoded string and for decrypting You should call openssl_decrypt not openssl_encrypt :-)

you are using getBytes in java
instead use getBytes(Charset) method to ensure the same encoding of the key and plaintext as the one used in php
(dump the byte array in both and see if they match before you go on)

Some remarks:
the key size is not explicit in the java program
did you check what is the block cipher modes of operation of both programs ? CBC, ECB, OFB, etc... ? Some can require an IV to passe with the encrypted data.
last idea: what is the padding used by the Java and PHP programs ?
This document can help you: you have all the valid combinations cipher / block cipher mode / padding mode / key size.

I have just got this working.
The thing to do is to encode the string as UTF-8 before padding and then send the byte array to encrypt.
UTF-8 represents accented characters as two hex bytes c3 xx so the converted string will be longer if it contains characters that need to be encoded. BTW the c3 character is "A" with a "~" on top so if your decryption shows up with these odd characters then you haven't recoded the decryption.
import java.security.NoSuchAlgorithmException;
import javax.crypto.Cipher;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;
import android.util.Log;
public class MCrypt {
private IvParameterSpec ivspec;
private SecretKeySpec keyspec;
private Cipher cipher;
private String iv = "cant hear you";
private String SecretKey = "top secret";
public MCrypt()
{
ivspec = new IvParameterSpec(iv.getBytes());
keyspec = new SecretKeySpec(SecretKey.getBytes(), "AES");
try {
cipher = Cipher.getInstance("AES/CBC/NoPadding");
} catch (NoSuchAlgorithmException e) {
e.printStackTrace();
} catch (NoSuchPaddingException e) {
e.printStackTrace();
}
}
public byte[] encrypt(String text) throws Exception{
if(text == null || text.length() == 0) throw new Exception("Empty string");
byte[] bs = text.getBytes("UTF-8");
byte[] toEncrypt = padBytes(bs);
byte[] encrypted = null;
try {
cipher.init(Cipher.ENCRYPT_MODE, keyspec, ivspec);
encrypted = cipher.doFinal(toEncrypt);
} 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 byte[] padBytes(byte[] source){
char paddingChar = ' ';
int size = 16;
int x = source.length % size;
int padLength = size - x;
int bufferLength = source.length + padLength;
byte[] ret = new byte[bufferLength];
int i = 0;
for ( ; i < source.length; i++){
ret[i] = source[i];
}
for ( ; i < bufferLength; i++){
ret[i] = (byte)paddingChar;
}
return ret;
}
} // class close
The pHp side is similar... ( I cannot figure out how to enter pHp code here!!!!
class MCrypt
{
private $iv = 'adfdadfgfd'; #Same as in JAVA
private $key = 'adfadfdfdafadfa'; #Same as in JAVA
function __construct()
{
}
function encrypt($str) {
$iv = $this->iv;
$td = mcrypt_module_open('rijndael-128', '', 'cbc', $iv);
mcrypt_generic_init($td, $this->key, $iv);
$s = padString(utf8_encode($str));
$encrypted = mcrypt_generic($td, $s);
//echo $encrypted;
mcrypt_generic_deinit($td);
mcrypt_module_close($td);
return bin2hex($encrypted);
}
function decrypt($code) {
$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($td);
return (trim(utf8_decode($decrypted)));
}
protected function hex2bin($hexdata) {
$bindata = '';
for ($i = 0; $i < strlen($hexdata); $i += 2) {
$bindata .= chr(hexdec(substr($hexdata, $i, 2)));
}
return $bindata;
}
}
that's it, quite straightforward really... Oh by the way, if you do the padding yourself then it does not matter if the method is Padding or NoPadding!

Java decrypt error: data not block size aligned

I'm trying to encrypt data between my android application and a PHP webservice.
I found the next piece of code in this website: http://schneimi.wordpress.com/2008/11/25/aes-128bit-encryption-between-java-and-php/
But when I try to decrypt I get the Exception of the title "data not block size aligned"
This are the method in my MCrypt class
public String encrypt(String text) throws Exception
{
if(text == null || text.length() == 0)
throw new Exception("Empty string");
Cipher cipher;
byte[] encrypted = null;
try {
cipher = Cipher.getInstance("AES/CBC/NoPadding");
cipher.init(Cipher.ENCRYPT_MODE, keyspec, ivspec);
encrypted = cipher.doFinal(padString(text).getBytes());
} catch (Exception e)
{
throw new Exception("[encrypt] " + e.getMessage());
}
return new String( encrypted );
}
public String decrypt(String code) throws Exception
{
if(code == null || code.length() == 0)
throw new Exception("Empty string");
Cipher cipher;
byte[] decrypted = null;
try {
cipher = Cipher.getInstance("AES/CBC/NoPadding");
cipher.init(Cipher.DECRYPT_MODE, keyspec, ivspec);
decrypted = cipher.doFinal(hexToBytes(code));
} catch (Exception e)
{
throw new Exception("[decrypt] " + e.getMessage());
}
return new String( decrypted );
}
private static byte[] hexToBytes(String hex) {
String HEXINDEX = "0123456789abcdef";
int l = hex.length() / 2;
byte data[] = new byte[l];
int j = 0;
for (int i = 0; i < l; i++) {
char c = hex.charAt(j++);
int n, b;
n = HEXINDEX.indexOf(c);
b = (n & 0xf) << 4;
c = hex.charAt(j++);
n = HEXINDEX.indexOf(c);
b += (n & 0xf);
data[i] = (byte) b;
}
return data;
}
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;
}
And this is how I'm using it in my activity to test:
String encrypted = mcrypt.encrypt(jsonUser.toString());
String decrypted = mcrypt.decrypt(encrypted);
the encrypt method works fine, but the second throws an exception.

At last! I made it work! Thanks for all your suggestion. I would like to share the code just in case somebody get stuck like me:
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;
}
}
HOW TO USE IT (JAVA)
mcrypt = new MCrypt();
/* Encrypt */
String encrypted = MCrypt.bytesToHex( mcrypt.encrypt("Text to Encrypt") );
/* Decrypt */
String decrypted = new String( mcrypt.decrypt( encrypted ) );
====================================================
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;
}
}
HOW TO USE IT (PHP)
<?php
$mcrypt = new MCrypt();
#Encrypt
$encrypted = $mcrypt->encrypt("Text to encrypt");
#Decrypt
$decrypted = $mcrypt->decrypt($encrypted);

I'm guessing your keyspec and ivspec are not valid for decryption. I've typically transformed them into PublicKey and PrivateKey instances and then use the private key to decrypt.

I looked at the comments in the other answer. I ran into a similar problem trying to encrypt a large block of text using open SSL in php (on both sides). I imagine the same issue would come up in Java.
If you have a 1024 bit RSA key, you must split the incoming text into 117 byte chunks (a char is a byte) and encrypt each (you can concatenate them together). On the other end, you must split the encrypted data into 128 byte chunks and decrypt each. This should give you your original message.
Also note that http may not play friendly with the non-ASCII encrypted data. I base64 encode/decode it before and after transmission (plus you have to worry about additional urlencoding for the base64 change, but it is easy).
I'm not sure of your AES key length, but if it's 1024 bits the chunk length is probably the same. If it's not, you will have to divide the bits by 8 to find the byte chunk length coming out. I'm actually not sure how to get it coming in, unfortunately (maybe multiply by 117/128 ?)
Here's some php code:
class Crypto {
public function encrypt($key, $data) {
$crypto = '';
foreach (str_split($data, 117) as $chunk) {
openssl_public_encrypt($chunk, $encrypted, $key);
$crypto .= $encrypted;
}
return $crypto;
}
//Decrypt omitted. Basically the same, change 117 to 128.
/**##+
* Update data for HTTP transmission and retrieval
* Must be used on encrypted data, but also useful for any binary data
* (e.g. zip files).
*/
public function base64_encode($value) {
return rtrim(strtr(base64_encode($value), '+/', '-_'), '=');
}
//String length must be padded for decoding for some reason
public function base64_decode($value) {
return base64_decode(str_pad(strtr($value, '-_', '+/')
, strlen($value) % 4, '=', STR_PAD_RIGHT));
}
/**##-*/
}