I have algorithm of encryption\ decryption files:
private static byte[] encrypt(byte[] raw, byte[] clear) throws Exception { SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES"); Cipher cipher = Cipher.getInstance("AES/ECB/PKCS5Padding"); cipher.init(Cipher.ENCRYPT_MODE, skeySpec); byte[] encrypted = cipher.doFinal(clear); return encrypted; } private static byte[] getRawKey(byte[] seed) throws Exception { KeyGenerator kgen = KeyGenerator.getInstance("AES"); SecureRandom sr = new SecureRandom(); sr.setSeed(seed); kgen.init(sr); // 192 and 256 bits may not be available SecretKey skey = kgen.generateKey(); byte[] raw = skey.getEncoded(); return raw; } private static byte[] decrypt(byte[] raw, byte[] encrypted) throws Exception { SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES"); Cipher cipher = Cipher.getInstance("AES/ECB/PKCS5Padding"); cipher.init(Cipher.DECRYPT_MODE, skeySpec); byte[] decrypted = cipher.doFinal(encrypted); return decrypted; }
It works great, but on Android 4.4 (api 19) I have strangely exception
javax.crypto.BadPaddingException: error:06065064:digital envelope routines:EVP_DecryptFinal_ex:bad decrypt
What is it?
Here what I got: http://www.logikdev.com/2010/11/01/encrypt-with-php-decrypt-with-java/
public class AES2 { private static final String TRANSFORMATION = "AES/CFB8/NoPadding"; private static final String ALGO_MD5 = "MD5"; private static final String ALGO_AES = "AES"; /** * See http://www.logikdev.com/2012/12/12/md5-generates-31-bytes-instead-of-32/ form more detail. * * @param input * @return * @throws NoSuchAlgorithmException */ private static String md5(String input) throws NoSuchAlgorithmException { MessageDigest md = MessageDigest.getInstance(ALGO_MD5); byte[] messageDigest = md.digest(input.getBytes()); BigInteger number = new BigInteger(1, messageDigest); return String.format("%032x", number); } public static String decrypt(String encryptedData, String initialVectorString, String secretKey) { String decryptedData = null; try { String md5Key = md5(secretKey); SecretKeySpec skeySpec = new SecretKeySpec(md5Key.getBytes(), ALGO_AES); IvParameterSpec initialVector = new IvParameterSpec(initialVectorString.getBytes()); Cipher cipher = Cipher.getInstance(TRANSFORMATION); cipher.init(Cipher.DECRYPT_MODE, skeySpec, initialVector); byte[] encryptedByteArray = Base64.decode(encryptedData.getBytes(), Base64.DEFAULT); byte[] decryptedByteArray = cipher.doFinal(encryptedByteArray); decryptedData = new String(decryptedByteArray); } catch (NoSuchAlgorithmException e) { e.printStackTrace(); } catch (NoSuchPaddingException e) { e.printStackTrace(); } catch (InvalidKeyException e) { e.printStackTrace(); } catch (InvalidAlgorithmParameterException e) { e.printStackTrace(); } catch (IllegalBlockSizeException e) { e.printStackTrace(); } catch (BadPaddingException e) { e.printStackTrace(); } return decryptedData; } }
So you have to create a initialVectorString (example: "fedcba9876543210"). Hope this help.
