使用Java的AES加密和解密 [英] AES Encryption and Decryption with Java

问题描述

这里是我正在做的，可以看起来有点笨拙，但任何帮助，感谢关于这个问题。阅读几乎所有相关主题，但没有找到适当的解决方案。我是加密解密编程的新手，需要在我的一个Java应用程序中实现它。

Here is what I am doing which can look a bit clumsy but any help is appreciated regarding the problem. Read almost all related topics but didn't find the appropriate solution. I am new to encryption decryption programming and need to implement it in one of my Java application.

谢谢..
这是代码的外观。 ..

Thank You.. this is how the code looks....

public static void main(String[] args) throws NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException, IllegalBlockSizeException, BadPaddingException {
    // TODO Auto-generated method stub
            String FileName="encryptedtext.txt";
            String FileName2="decryptedtext.txt";
            String pad="0"; 

            KeyGenerator KeyGen=KeyGenerator.getInstance("AES");
            KeyGen.init(128);

            SecretKey SecKey=KeyGen.generateKey();

            Cipher AesCipher=Cipher.getInstance("AES");
            AesCipher.init(Cipher.ENCRYPT_MODE,SecKey);

            byte[] byteText="My name is yogesh".getBytes();
            byte[] byteCipherText=AesCipher.doFinal(byteText);
            String cipherText = null;

            try {
                FileWriter fw=new FileWriter(FileName);
                BufferedWriter bw=new BufferedWriter(fw);
                bw.write(byteCipherText.toString());
                bw.close();
            }catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }

            try {
                FileReader fr=new FileReader(FileName);
                BufferedReader br=new BufferedReader(fr);
                cipherText=br.readLine();
                br.close();
            } catch (FileNotFoundException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }

            AesCipher.init(Cipher.DECRYPT_MODE,SecKey);
            while(((cipherText.getBytes().length)%16)!=0)
            {
                cipherText=cipherText+pad;


            }

            byte[] bytePlainText=AesCipher.doFinal(cipherText.getBytes());
            FileWriter fw1;
            try {
                fw1 = new FileWriter(FileName2);
                BufferedWriter bw1=new BufferedWriter(fw1);
                bw1.write(bytePlainText.toString());
                bw1.close();

            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }






}

推荐答案

在这里，你必须理解的是，密文不一定是一组可打印的字符。因此，当你使用readLine（）时，它不会给你文件中的所有字节。

Here, what you have to understand is a cipher text is not necessarily be a set of printable characters. So, when you user readLine(), it will no give you all the bytes in the file.

另外， byteCipherText.toString / code>不给你你以为你会得到。在java中，toString（）方法不给出数组内容的字符串表示。

Also, byteCipherText.toString() does not gives you what you thought you would get. In java, toString() method does not give the string representation of the contents of the array.

不需要对加密文本添加填充。它已经被填充。​​

There is no need to add padding to encrypted text. It is already padded.

import java.nio.file.Files;
import java.nio.file.Paths;
import javax.crypto.*;

public class Main {

    public static void main(String[] args) throws Exception {
        String FileName = "encryptedtext.txt";
        String FileName2 = "decryptedtext.txt";

        KeyGenerator KeyGen = KeyGenerator.getInstance("AES");
        KeyGen.init(128);

        SecretKey SecKey = KeyGen.generateKey();

        Cipher AesCipher = Cipher.getInstance("AES");


        byte[] byteText = "Your Plain Text Here".getBytes();

        AesCipher.init(Cipher.ENCRYPT_MODE, SecKey);
        byte[] byteCipherText = AesCipher.doFinal(byteText);
        Files.write(Paths.get(FileName), byteCipherText);


        byte[] cipherText = Files.readAllBytes(Paths.get(FileName));

        AesCipher.init(Cipher.DECRYPT_MODE, SecKey);
        byte[] bytePlainText = AesCipher.doFinal(cipherText);
        Files.write(Paths.get(FileName2), bytePlainText);
    }
}

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