Java文件加密

Question

我正在尝试使用AES算法编写一个简单的程序来加密和解密文件.我没有加密问题,但解密..

public static void main(String[] args) throws NoSuchAlgorithmException, FileNotFoundException, InvalidKeyException, NoSuchPaddingException, IllegalBlockSizeException, BadPaddingException {

    // ????????????? ????????? ??????
    KeyGenerator keyGenS = KeyGenerator.getInstance("AES");
    keyGenS.init(128);
    SecretKey sKey1 = keyGenS.generateKey();
    SecretKey sKey2 = keyGenS.generateKey();
    // ??????? ????????? ?????? ? ?????? ? ?????? ? ????
    String key1 = SecretKeyToString(sKey1);
    String key2 = SecretKeyToString(sKey2);

    spreader.write(fileName1, key1);
    spreader.write(fileName2, key2);
    spreader.write(fileNameS1, key1);
    spreader.write(fileNameS2, key2);


    // ?????? ????????? ?????? ?? ????? ? ??????? ??????? ? ??? SecretKey
    key1 = spreader.read(fileName1);
    System.out.println("????????? ???? 1?? ????????????: " +key1);


    SecretKey seansKey1=getKeyInstance(key1);

    key2 = spreader.read(fileName2);
    System.out.println("????????? ???? 2?? ????????????: " +key2);

    SecretKey seansKey2=getKeyInstance(key2);


    //????????????? ? ???????????? ?????????? ????? ? ??????? ?????????
    Cipher aesCipher = Cipher.getInstance("AES");
    aesCipher.init(Cipher.ENCRYPT_MODE,seansKey1);

    KeyGenerator keyGen = KeyGenerator.getInstance("AES");
    keyGen.init(128);
    SecretKey secretKey = keyGen.generateKey();

    String stringsecretKey = SecretKeyToString(secretKey);
    byte[] byteKey = stringsecretKey.getBytes();
    byte[] byteCipherKey1 = aesCipher.doFinal(byteKey); 
    String encryptedKey = new BASE64Encoder().encode(byteCipherKey1);
    System.out.println("????????????? ????????? ???? ? ??????? ?????????? ????? 1: " +encryptedKey);





    aesCipher = Cipher.getInstance("AES");
    aesCipher.init(Cipher.ENCRYPT_MODE,SeansKey2);


     byteKey = etringsecretKey.getBytes();
     byte[] byteCipherKey2 = aesCipher.doFinal(byteKey); 
     encryptedKey = new BASE64Encoder().encode(byteCipherKey2);
    System.out.println("????????????? ????????? ???? ? ??????? ?????????? ????? 2: " +encryptedKey);
    spreader.write(fileNameEK2, encryptedKey);

    //?????? ?????? ?? ?????
    String text =spreader.read(fileName);
    System.out.println(text);

    // ???????????? ??????


            aesCipher.init(Cipher.ENCRYPT_MODE,secretKey); // ??????????? ??????????

            byte[] byteText = text.getBytes();
            byte[] byteCipherText = aesCipher.doFinal(byteText); 
            encryptedText = new BASE64Encoder().encode(byteCipherText);
            System.out.println("????????????? ?????: " +encryptedText);

            spreader.write(fileNameOK, encryptedText);





}

这是解密部分:

public static void main(String[] args) throws NoSuchAlgorithmException, FileNotFoundException, InvalidKeyException, NoSuchPaddingException, IllegalBlockSizeException, BadPaddingException, InvalidAlgorithmParameterException, UnsupportedEncodingException {

    String encryptedText = user.read(fileNameOK);
    String key1 = user.read(fileName1);
    String key2 = user.read(fileName2);
    String encryptedSeanceKey1 = user.read(fileNameEK1);
    String encryptedSeanceKey2 = user.read(fileNameEK2);




    SecretKey secretKey1=getKeyInstance(key1);
    SecretKey secretKey2=getKeyInstance(key2);



    Cipher aesCipher = Cipher.getInstance("AES");
    aesCipher.init(Cipher.DECRYPT_MODE,secretKey1,aesCipher.getParameters());




    //byte[] byteKey = encryptedSeanceKey1.getBytes();

       byte[] byteDecryptedKey = aesCipher.doFinal(encryptedSeanceKey1.getBytes());
       String decryptedKey1 = new String(byteDecryptedKey);
       System.out.println("?????????????? ????????? ???? ? ??????? ?????????? ????? 1: " +decryptedKey1);

    aesCipher.init(Cipher.DECRYPT_MODE,secretKey2,aesCipher.getParameters());




    byte[] byteKey2 = encryptedSeanceKey2.getBytes();
        byteDecryptedKey = aesCipher.doFinal(byteKey2); 
        String decryptedKey2 = new String(byteDecryptedKey);
       System.out.println("?????????????? ????????? ???? ? ??????? ?????????? ????? 2: " +decryptedKey2);





        // ????????????? ??????
        aesCipher.init(Cipher.DECRYPT_MODE,getKeyInstance(decryptedKey1),aesCipher.getParameters());

         byte[] byteText = encryptedText.getBytes();

        byte[] byteDecryptedText = aesCipher.doFinal(byteText);
        decryptedText = new String(byteDecryptedText);
        System.out.println(" ?????????????? ????? " +decryptedText);



}

}

现在的问题是解密部分是:当用填充密码解密时,输入长度必须是16的倍数

我知道我错误地保留会话密钥和字节的错误会丢失.但我怎么能正确地做到这一点？

Answer 1

您的代码中存在一些混淆,可能是因为您调用的某些方法丢失了,或者可能是因为您使用密钥加密...您的密钥(!!!)
让我们尝试加密和解密简单的方法,删除代码中不严格需要的所有内容(比如编码密钥并将其保存到文件中,然后在不解码的情况下恢复密钥等).

让我们看一下基于您的以下简化代码:

    KeyGenerator keyGenS = KeyGenerator.getInstance("AES");
    keyGenS.init(128);
    SecretKey sKey1 = keyGenS.generateKey();

    Cipher aesCipher = Cipher.getInstance("AES");
    aesCipher.init(Cipher.ENCRYPT_MODE,sKey1);

    byte[] byteText = "Insert here whatever you want to crypt".getBytes();

    byte[] byteCipherText = aesCipher.doFinal(byteText);

我们使用KeyGenerator生成了密钥,然后使用该密钥初始化了Cipher实例.此时我们只是调用doFinal()传递我们想要加密的plainText.
这就是加密部分的全部内容.当然,byteCipherText如果你愿意,你可以保存你的密钥和文件,但所有其他工作人员(至少)是无用的.

解密部分很容易作为加密.逻辑是一样的.如果您将密钥保存在文件中,只需将其读入a byte[],然后使用它来初始化密码实例.像这样的东西:

    aesCipher.init(Cipher.DECRYPT_MODE, sKey1);
    byte[] plainText = aesCipher.doFinal(byteCipherText);

如果您将上述所有代码放入main()并运行它,您应该使用与中plainText的相同的文本byteText.
你可以用一个验证它

    System.out.println(new String(plainText));

尝试从这里开始,然后添加您可能需要的所有其他东西.
希望这可以帮助.
问候