Question

我有一个关于客户端服务器输出无法正常工作的小错误。问题是从解密后，从我的服务器发送到客户端的输出并不总是相同。在这种情况下，得到的解密是相同的，只有一定的长度。

下面是输出，后面是源代码：

Server
Starting the socket server at port:9876
Waiting for clients...

GxModP = 2819481724922694722202990425920759863750647735434635820227489190230872167846391528548356160689879969739097933352014135386311977602583588682340466075235457

encrypted = Y:!T¤]®ð]áfyLkåª hÛÒ2{ø2/Z°ÿFär8 icÂÂñýÜå¼Níxv_Ö3?»>@×âÑÛm4ÁônûZùGÃêa¼/d
×Q¨_¬ù6øY¾½¡pOY÷?x¼ù>öMÀ|c´áúê±ôpZþÏÈy9½4S


decrypted = 2819481724922694722202990425920759863750647735434635820227489190230872167846391528548356160689879969739097933352014135386311977602583588682340466075235457


Client
Attempting to connect to localhost:9876
Connection Established

User input : Y:!T¤]®ð]áfyLkåª hÛÒ2{ø2/Z°ÿFär8 icÂÂñýÜå¼Níxv_Ö3?»>@×âÑÛm4ÁônûZùGÃêa¼/d

Gx mod P : 281948172492269472220299042592075986375064773543463582022748919023087216784639152854835616068987

我在这里做的是将加密放入客户端输入并解密加密的消息以便到达GxModP。但是，似乎GxModP的值只有一定长度才相同。谁能告诉我，我犯了什么错误导致这个？

我在下面附上了源代码以供参考

    private static String algorithm = "RC4";

            public static byte[] encryptRC4(String toEncrypt, String key) throws Exception {
              // create a binary key from the argument key (seed)
              SecureRandom sr = new SecureRandom(key.getBytes("ISO-8859-1"));
              KeyGenerator kg = KeyGenerator.getInstance(algorithm);
              kg.init(sr);
              SecretKey sk = kg.generateKey();

              // create an instance of cipher
              Cipher cipher = Cipher.getInstance(algorithm);

              // initialize the 

cipher with the key
          cipher.init(Cipher.ENCRYPT_MODE, sk);

          // enctypt!
          byte[] encrypted = cipher.doFinal(toEncrypt.getBytes("ISO-8859-1"));

          return encrypted;
        }

        public static String decryptRC4(byte[] toDecrypt, String key, int length) throws Exception {
          // create a binary key from the argument key (seed)
          SecureRandom sr = new SecureRandom(key.getBytes("ISO-8859-1"));
          KeyGenerator kg = KeyGenerator.getInstance(algorithm);
          kg.init(sr);
          SecretKey sk = kg.generateKey();

          // do the decryption with that key
          Cipher cipher = Cipher.getInstance(algorithm);
          cipher.init(Cipher.DECRYPT_MODE, sk);
          byte[] decrypted = cipher.doFinal(toDecrypt, 0, length);


          return new String(decrypted, "ISO-8859-1");
       }

服务器代码：

private void sendKey(Socket client) throws IOException {
    //calculate GxModP
    //encrypt + send over.

    String gXmodP = generateGxModP(g, p);
String temp = "";
System.out.println("GxModP = "+gXmodP);
try
{
    encryptedKey = EncryptionScheme.encryptRC4(gXmodP, password);
}catch(Exception e){}

String encrypted = new String(encryptedKey, "ISO-8859-1");

byte[] temp2 = encrypted.getBytes("ISO-8859-1");
System.out.println("encrypted = "+encrypted);
try
{
    temp = EncryptionScheme.decryptRC4(temp2, password, temp2.length);
}catch(Exception e){};
System.out.println("decrypted = " + temp);

BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(client.getOutputStream()));
writer.write(encrypted);
writer.flush();
writer.close();
}

客户代码

public void readResponse() throws IOException
{
    String userInput;
    BufferedReader stdIn = new BufferedReader(new InputStreamReader(socketClient.getInputStream()));
    String gXmodP = "";
    /*
    System.out.println("Response from server:");
    while ((userInput = stdIn.readLine()) != null) {
        System.out.println(userInput);*/ 
    //instead of reading response i will decrypt and print out

    userInput = stdIn.readLine();
    System.out.println("User input : " + userInput);
    byte [] toDecrypt = userInput.getBytes("ISO-8859-1");
    try
    {
        gXmodP = EncryptionScheme.decryptRC4(toDecrypt, password, toDecrypt.length);
    }catch(Exception e){};
    System.out.println("Gx mod P : " + gXmodP);
}

Answer 1

您处理加密输出的二进制结果的方式容易出错。您不应该直接将byte []转换为String并将其作为字符传输（使用类似Base64的编码或完全粘贴到二进制传输）。

在您的具体示例中，问题来自加密结果包含二进制中的换行符/ \ n。因此，客户端上的readLine();会在那里剪切二进制字符串，因此您的解密文本也会被删除。否则，您的加密代码运行得非常好。

但我不会评论使用RC-4。

byte []在UDP中发送java无法给出全部值

1 个答案: