java中的Aes解密 - 填充问题

Question

我想在java中实现一个简单的加密/解密工具。 因此，我找到了一个小教程：http://www.codejava.net/coding/file-encryption-and-decryption-simple-example

我改变了一些代码行，以保证大文件的加密。 现在我遇到了问题，解密不起作用。

，我得到了以下错误消息/异常：

Error encrypting/decrypting file 
    at Algorithmus.Encryptor.doCrypto(Encryptor.java:71) 
    at Algorithmus.Encryptor.decrypt(Encryptor.java:39) 
    at GUI.MainWindow$encryptThread.run(MainWindow.java:838) 
Caused by: javax.crypto.BadPaddingException: Given final block not properly padded 
    at com.sun.crypto.provider.CipherCore.doFinal(CipherCore.java:966) 
    at com.sun.crypto.provider.CipherCore.doFinal(CipherCore.java:824) 
    at com.sun.crypto.provider.AESCipher.engineDoFinal(AESCipher.java:436) 
    at javax.crypto.Cipher.doFinal(Cipher.java:2165) 
    at Algorithmus.Encryptor.doCrypto(Encryptor.java:60) 
    ... 2 more 

我试图Transoformation参数更改为AES/CBC/PKCS5Padding但没有任何效果。有谁知道，如何优化给定的代码？

 private static final String ALGORITHM = "AES"; 

     private static final String TRANSFORMATION = "AES"; 

     public static void encrypt(String key, File inputFile, File outputFile) 
       throws ExtendedException { 
      doCrypto(Cipher.ENCRYPT_MODE, key, inputFile, outputFile); 
     } 

     public static void decrypt(String key, File inputFile, File outputFile) 
       throws ExtendedException { 
      doCrypto(Cipher.DECRYPT_MODE, key, inputFile, outputFile); 
     } 

     private static void doCrypto(int cipherMode, String key, File inputFile, 
       File outputFile) throws ExtendedException { 
      try { 
       Key secretKey = new SecretKeySpec(key.getBytes(), ALGORITHM); 
       Cipher cipher = Cipher.getInstance(TRANSFORMATION); 
       cipher.init(cipherMode, secretKey); 

       FileInputStream inputStream = new FileInputStream(inputFile); 


       CipherOutputStream out = new CipherOutputStream(new FileOutputStream(outputFile), cipher); 
       byte[] buffer = new byte[8192]; 
       byte[] outputBytes = null; 
       FileOutputStream outputStream = new FileOutputStream(outputFile); 
       int count; 
       while ((count = inputStream.read(buffer)) > 0) 
       { 
        out.write(buffer, 0, count); 
        outputBytes = cipher.doFinal(buffer); 

       } 


       inputStream.close(); 
       outputStream.close(); 

      } catch (NoSuchPaddingException | NoSuchAlgorithmException 
        | InvalidKeyException | BadPaddingException 
        | IllegalBlockSizeException | IOException ex) { 
       throw new ExtendedException("Error encrypting/decrypting file", ex); 
      } 
     } 

Answer 1

只需使用CipherOutputStream。不要调用cipher.doFinal(buffer)，不要忘记关闭输出流。

FileInputStream inputStream = new FileInputStream(inputFile); 
FileOutputStream fileout = new FileOutputStream(outputFile); 
CipherOutputStream out = new CipherOutputStream(fileout , cipher); 

try { 
    byte[] buffer = new byte[8192]; 
    int count; 

    while ((count = inputStream.read(buffer)) > 0) { 
     out.write(buffer, 0, count); 
    } 
} finally { 
    out.close(); 
    inputStream.close(); 
} 

CipherOutputStream管理你的密码。当流将被关闭并刷新内部缓冲区时，它调用doFinal。