AES 256 CBC encryption in Laravel and Decryption in android

问题:

So my problem is this: i have a password that i'm encrypting in Laravel 5.6 with AES-256-CBC and send it to an android device, problem is i can't find a way to decrypt it knowing that i found a way to extract the IV and the encrypted value and the key is available on the android device !

I'm successfully decrypting the value if i use AES-128-CBC using this code on the android device, but failing the AES-256-CBC cypher and i don't understand where the problem is ! The code :

public static String decrypt(byte[] keyValue, String ivValue, String encryptedData) throws Exception {     Key key = new SecretKeySpec(keyValue, "AES");     byte[] iv = Base64.decode(ivValue.getBytes("UTF-8"), Base64.DEFAULT);     byte[] decodedValue = Base64.decode(encryptedData.getBytes("UTF-8"), Base64.DEFAULT);     Cipher c = Cipher.getInstance("AES/CBC/PKCS7Padding");     c.init(Cipher.DECRYPT_MODE, key, new IvParameterSpec(iv));     byte[] decValue = c.doFinal(decodedValue);     return new String(decValue); } 

At what instance it's specified that this code should use AES-128 and not 256 ? and how can i change it !

Thanks in advance !

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EDIT

the PHP code is as follows :

$cipher="AES-256-CBC"; $key='somerandomkeyof32byteslong'; $crypt=new Encrypter($key,$cipher); $result=$crypt->encryptString('oussama'); //i'm sending the result to the android device 

回答1:

Try this one

Security.java

import javax.crypto.Cipher; import javax.crypto.spec.SecretKeySpec;  import org.apache.commons.codec.binary.Base64;  public class Security { public static String encrypt(String input, String key){   byte[] crypted = null;   try{     SecretKeySpec skey = new SecretKeySpec(key.getBytes(), "AES");       Cipher cipher = Cipher.getInstance("AES/ECB/PKCS5Padding");       cipher.init(Cipher.ENCRYPT_MODE, skey);       crypted = cipher.doFinal(input.getBytes());     }catch(Exception e){         System.out.println(e.toString());     }     return new String(Base64.encodeBase64(crypted)); }  public static String decrypt(String input, String key){     byte[] output = null;     try{       SecretKeySpec skey = new SecretKeySpec(key.getBytes(), "AES");       Cipher cipher = Cipher.getInstance("AES/ECB/PKCS5Padding");       cipher.init(Cipher.DECRYPT_MODE, skey);       output = cipher.doFinal(Base64.decodeBase64(input));     }catch(Exception e){       System.out.println(e.toString());     }     return new String(output); }  public static void main(String[] args) {   String key = "1234567891234567";   String data = "example";   System.out.println(Security.decrypt(Security.encrypt(data, key), key));   System.out.println(Security.encrypt(data, key));       }    } 

Security.php

class Security {     public static function encrypt($input, $key) {     $size = mcrypt_get_block_size(MCRYPT_RIJNDAEL_128, MCRYPT_MODE_ECB);             $input = Security::pkcs5_pad($input, $size);      $td = mcrypt_module_open(MCRYPT_RIJNDAEL_128, '', MCRYPT_MODE_ECB, '');      $iv = mcrypt_create_iv (mcrypt_enc_get_iv_size($td), MCRYPT_RAND);     mcrypt_generic_init($td, $key, $iv);      $data = mcrypt_generic($td, $input);      mcrypt_generic_deinit($td);      mcrypt_module_close($td);      $data = base64_encode($data);      return $data;  }   private static function pkcs5_pad ($text, $blocksize) {      $pad = $blocksize - (strlen($text) % $blocksize);      return $text . str_repeat(chr($pad), $pad);  }   public static function decrypt($sStr, $sKey) {     $decrypted= mcrypt_decrypt(         MCRYPT_RIJNDAEL_128,         $sKey,          base64_decode($sStr),          MCRYPT_MODE_ECB     );     $dec_s = strlen($decrypted);      $padding = ord($decrypted[$dec_s-1]);      $decrypted = substr($decrypted, 0, -$padding);     return $decrypted; }    }?> 

Example.php

<?php include 'security.php';  $value = 'plain text';  $key = "your key"; //16 Character Key  echo "Encrypt =>"."<br><br>"; echo  Security::encrypt($value, $key);  echo "<br><br>"."Decrypt =>"."<br><br>";  echo Security::decrypt("AES Encrypted response",$key); //echo Security::decrypt(Security::encrypt($value, $key), $key);  ?> 

回答2:

If you need AES with 256 bit key length, you can do it like this:

Cipher c = Cipher.getInstance("AES_256/CBC/PKCS7Padding"); 

Android reference sometimes better than oracle when you want to use java classes for android. Here is reference.

But remember that is only api 26+. You can compile openssl and use it in an JNI if you need support for previous versions(and I think you need to do). or find another cryptographic library for java.

文章来源: AES 256 CBC encryption in Laravel and Decryption in android