加密解密问题

Question

使用Cipher类进行对字符串的加密解密，加密没有问题，解密的时候老是出现javax.crypto.IllegalBlockSizeException错误，请问怎么办啊？我粘的诺基亚网站上的代码。
好像要长是8的倍数。
但我不知道为什么
String str = new String(outputBytes, 0, 8);
inputBytes = str.getBytes();
inputBytes 的长度是7
代码如下：
        // Object of this class provides the functionality for
        // encryption and decryption.
        Cipher cipher;
        try {
            // parameter "DES" specifies type of cipher we want to create
            // through the factory method. It includes algorithm, mode and
            // padding. You can define only algorithm and in that case default
            // values will be used for mode and padding.
            cipher = Cipher.getInstance("DES/ECB/PKCS5Padding");
        } catch (NoSuchAlgorithmException ex) {
            // requested cryptographic algorithm is not available
            printString(ex.toString());
            printString("Error! Snippets execution stopped.");
            return;
        } catch (NoSuchPaddingException ex) {
            // requested padding mechanism is not available in the environment.
            printString(ex.toString());
            printString("Error! Snippets execution stopped.");
            return;
        }
        // The lenght of keyString is 8. It's important characteristic
        // for encryption
        String keyString = "testtest";
        byte[] keyData = keyString.getBytes();
        // key object specifies a secret key
        // it uses to construct the secret key for our cipher object from a byte
        // array
        SecretKeySpec key = new SecretKeySpec(keyData, 0, keyData.length, "DES");
        try {
            // initializing with setting up the type of operation it's to be
            // used for. In this case - for encryption.
            cipher.init(Cipher.ENCRYPT_MODE, key);
        } catch (InvalidKeyException ex) {
            // given key object is inappropriate for initializing this cipher
            printString(ex.toString());
            printString("Error! Snippets execution stopped.");
            return;
        }
        int cypheredBytes = 0;
        printString("Source string: " + textToCrypting);
        byte[] inputBytes = textToCrypting.getBytes();
        byte[] outputBytes = new byte[100];
        try {
            // doFinal method encrypts data to outputBytes array.
            // for unknown or big counts of data update method more recomended
            // counts of crypted bytes saved inside cypheredBytes variable
            
            cypheredBytes = cipher.doFinal(inputBytes, 0, inputBytes.length,
                    outputBytes, 0);
        } catch (IllegalStateException ex) {
            printString(ex.toString());
            printString("Error! Snippets execution stopped.");
            return;        } catch (ShortBufferException ex) {
            printString(ex.toString());
            printString("Error! Snippets execution stopped.");
            return;
        } catch (IllegalBlockSizeException ex) {
            printString(ex.toString());
            printString("Error! Snippets execution stopped.");
            return;
        } catch (BadPaddingException ex) {
            printString(ex.toString());
            printString("Error! Snippets execution stopped.");
            return;
        }
        String str = new String(outputBytes, 0, cypheredBytes);
        inputBytes = str.getBytes();
        printString("Crypted string:" + str);
        try {
            cipher.init(Cipher.DECRYPT_MODE, key);
        } catch (InvalidKeyException ex) {
            printString(ex.toString());
            printString("Error! Snippets execution stopped.");
            return;
        }
        try {
            // decrypts data
            cypheredBytes = cipher.doFinal(inputBytes, 0, inputBytes.length,
                    outputBytes, 0);
        } catch (IllegalStateException ex) {
            printString(ex.toString());
            printString("Error! Snippets execution stopped.");
            return;
        } catch (ShortBufferException ex) {
            printString(ex.toString());
            printString("Error! Snippets execution stopped.");
            return;
        } catch (IllegalBlockSizeException ex) {
            printString(ex.toString());
            printString("Error! Snippets execution stopped.");
            return;
        } catch (BadPaddingException ex) {
            printString(ex.toString());
            printString("Error! Snippets execution stopped.");
            return;
        }
        str = new String(outputBytes, 0, cypheredBytes);
        printString("Decrypted string:" + str);
        printString(" Ok!   " + str);

Answer 1

http://blog.csdn.net/jiangfeng861016/archive/2009/11/01/4755675.aspx

Answer 2

http://topic.csdn.net/u/20100512/19/c7dcc2fa-a561-4d81-9969-b31bea3bfacc.html这里有个 DES 的加密解密代码。你这代码抛出的异常也不知道是哪一行抛出来的！

Answer 3

我已经查出来了，就是在解密的时候 
cypheredBytes = cipher.doFinal(inputBytes, 0,inputBytes.length,outputBytes, 0);
这句话抛出的。原因是inputBytes.length为7。可我不知道该怎么解决啊

Answer 4

怎么突然那么多加解密帖？- -就是解密doFinal的时候被解密串非8的倍数，很好解决
inputBytes之前已经定长了，重新申请一个byte[] inputBytes1 = new byte[cypheredBytes];
try {
    str = new String(outputBytes, 0, cypheredBytes, "iso-8859-1");
    inputBytes1 = str.getBytes("iso-8859-1");
} catch(UnsupportedEncodingException e) {
    e.printStackTrace();
}

Answer 5

谢谢6楼，已经解决了，原来是要进行一下编码控制
try {
  str = new String(outputBytes, 0, cypheredBytes, "iso-8859-1");
  inputBytes1 = str.getBytes("iso-8859-1");
} catch(UnsupportedEncodingException e) {
  e.printStackTrace();
}
这样就可以了，也不用再申请inputBytes了。也谢谢上面各位，结贴了

Answer 6

是的，犯了个概念错误，直接赋inputBytes