演示使用RSA公钥系统来交换实现机密性和完整性/认证的消息 [英] Demonstrate the use of RSA Public-key system to exchange messages that achieve confidentiality and integrity/authentication

问题描述

我试图演示使用RSA公钥系统来交换实现机密性和完整性/认证的消息。我试图加密在客户端的消息，并发送此信息到服务器端进行解密。我遇到的问题是我的代码不解密。它给我以下错误：

  javax.crypto.BadPaddingException：数据必须以零开始
。 security.rsa.RSAPadding.unpadV15（RSAPadding.java:308）
 at sun.security.rsa.RSAPadding.unpad（RSAPadding.java:255）
 at com.sun.crypto.provider.RSACipher。 a（DashoA13 * ..）
 at com.sun.crypto.provider.RSACipher.engineDoFinal（DashoA13 * ..）
 at javax.crypto.Cipher.doFinal（DashoA13 * ..）
在PKServer.decryptMessage（PKServer.java:36）
在PKServer.main（PKServer.java:69）
  

公钥客户端代码：

  import java.io. *; 
 import java.net。*; 
 import java.security。*; 
 import javax.crypto。*; 
 
 public class PKClient 
 {
 public static final int kBufferSize = 8192; 
 
 public static void main（String [] args）throws Exception 
 {
 
 try {
 //生成新密钥
 KeyPair keyPair = KeyPairGenerator.getInstance（RSA）。generateKeyPair（）; 
 PrivateKey privateKey = keyPair.getPrivate（）; 
 String message =快速的棕色狐狸跳过懒惰的狗。 
 
 //计算签名
签名实例= Signature.getInstance（SHA1withRSA）; 
 instance.initSign（privateKey）; 
 instance.update（（message）.getBytes（））; 
 byte [] signature = instance.sign（）; 
 
 //计算摘要
 MessageDigest sha1 = MessageDigest.getInstance（SHA1）; 
 byte [] digest = sha1.digest（（message）.getBytes（））; 
 
 //加密摘要
加密密码= Cipher.getInstance（RSA / ECB / PKCS1Padding）; 
 cipher.init（Cipher.ENCRYPT_MODE，privateKey）; 
 byte [] encryptedMsg = cipher.doFinal（digest）; 
 
 //将密钥存储在文件中
 ObjectOutputStream out = new ObjectOutputStream（new FileOutputStream（KeyFile.xx））; 
 out.writeObject（privateKey）; 
 out.close（）; 
 
 System.out.println（Client  -  Message：+ message）; 
 System.out.println（Client  -  Encrypted：+ PKServer.asHex（encryptedMsg））; 
 
 String host =localhost; 
 int port = 7999; 
 Socket s = new Socket（host，port）; 
 
 //打开流到密码服务器
 DataOutputStream os = new DataOutputStream（s.getOutputStream（））; 
 os.writeInt（encryptedMsg.length）; 
 os.write（encryptedMsg）; 
 os.writeInt（digest.length）; 
 os.write（digest）; 
 os.writeInt（signature.length）; 
 os.write（signature）; 
 
 os.flush（）; 
 os.close（）; 
 
 //关闭套接字
 s.close（）; 
 
} catch（Exception e）{
 e.printStackTrace（）; 
} 
} 
} 
  

公用密钥服务器代码：

  import java.io. *; 
 import java.net。*; 
 import java.security。*; 
 import javax.crypto。*; 
 
 public class PKServer 
 {
 public void decryptMessage（InputStream inStream）throws IOException，NoSuchAlgorithmException 
 {
 try {
 
 //从套接字创建数据输入流
 DataInputStream dis = new DataInputStream（inStream）; 
 
 //获取密钥
 ObjectInputStream in = new ObjectInputStream（new FileInputStream（KeyFile.xx））; 
 
 // ObjectOutputStream outSocket = new ObjectOutputStream（s.getOutputStream（））; 
 
 PrivateKey privatekey =（PrivateKey）in.readObject（）; 
 System.out.println（Key Used：+ in.toString（））; 
 in.close（）; 
 
 //启动密码
 Cipher cipher = Cipher.getInstance（RSA / ECB / PKCS1Padding）; 
 cipher.init（Cipher.DECRYPT_MODE，privatekey）; 
 
 int len = dis.readInt（）; 
 byte [] encryptedMsg = new byte [len]; 
 dis.readFully（encryptedMsg）; 
 
 System.out.println（Server  -  Msg Length：+ len）; 
 System.out.println（Server  -  Encrypted：+ asHex（encryptedMsg））; 
 
 //  - 打印解密字符串以查看它是否与原始消息匹配。 
 byte [] plainText = cipher.doFinal（encryptedMsg）; 
 System.out.println（Decrypted Message：+ new String（plainText，SHA））; 
 
 
} catch（Exception e）{
 e.printStackTrace（）; 
} 
} 
 
 //使字节可打印的函数（十六进制格式）
 public static String asHex（byte buf []）{
 StringBuilder strbuf = new StringBuilder（buf.length * 2）; 
 int i; 
 for（i = 0; i  if（（int）buf [i]& 0xff）<0x10）{
 strbuf.append （0）; 
} 
 strbuf.append（Long.toString（（int）buf [i]& 0xff，16））; 
} 
 return strbuf.toString（）; 
} 
 public static void main（String [] args）throws Exception 
 {
 int port = 7999; 
 ServerSocket server = new ServerSocket（port）; 
 Socket s = server.accept（）; 
 
 
 PKServer cs = new PKServer（）; 
 cs.decryptMessage（s.getInputStream（））; 
 
 server.close（）; 
} 
} 
  

这是我在服务器端收到的输出：

 使用的密钥：java.io.ObjectInputStream@fee4648 
服务器 - 消息长度：128 
服务器 - 加密：8c23b2cd96c07950f4901a670b025531b5f52be0730e4548c9a76090d7ae65a8ce82901c66acfb6bd79520cf8d86bf74bf3105fd638892a681a6905556cbadf394915fbdc09babb5b78b9dd06382e92604e9ca88901613520ccb45fcc376e813df059ebc649c52f233dc2632733d99212b42ce54e59ebd6d9dca98af36a20fc6 
 javax.crypto.BadPaddingException：数据必须开始与sun.security.rsa.RSAPadding.unpadV15（RSAPadding.java:308）
零
。在sun.security.rsa。 RSAPadding.unpad（RSAPadding.java:255）
 at com.sun.crypto.provider.RSACipher.a（DashoA13 * ..）
 at com.sun.crypto.provider.RSACipher.engineDoFinal（DashoA13 * ..）
 at PKCS.m.m（PKServer.java：PKServer.java）上的
在PKServer.main（PKServer.java:36） 69）
  

我注意到如果我调整行：

  Cipher cipher = Cipher.getInstance（RSA / ECB / PKCS1Padding）; 
  

到

  Cipher cipher = Cipher.getInstance（RSA / ECB / NoPadding）; 
  

程序会解密，但不会解密到预期的字符串。它看起来像这样：

 解密消息：E ???。1G？：*？$ ?? | α
 VO）Zjap6 - △T * ？：？（？C？，??'??`（？2D？mC？OLc <7？？？？？？？
  pre> 
 
 
请让我知道，如果你能看到我在这个代码错误。
解决方案
您需要使用 PKClient 中的公钥对您的摘要进行加密：
  KeyPair keyPair = KeyPairGenerator.getInstance（RSA）。generateKeyPair（）; 
 Key pubKey = keyPair.getPublic（）; //添加这个
 PrivateKey privateKey = keyPair.getPrivate（）; 
 //几行之后... 
 //启动密码
 cipher.init（Cipher.ENCRYPT_MODE，pubKey）; //将privateKey更改为pubKey 
  
 
I'm trying to demonstrate the use of RSA Public-key system to exchange messages that achieve confidentiality and integrity/authentication.  I am trying to encrypt a message on the client side and send this information to the server side to decrypt.  The issue I am having is that my code is not decrypting.  It is giving me the following error:
javax.crypto.BadPaddingException: Data must start with zero
    at sun.security.rsa.RSAPadding.unpadV15(RSAPadding.java:308)
    at sun.security.rsa.RSAPadding.unpad(RSAPadding.java:255)
    at com.sun.crypto.provider.RSACipher.a(DashoA13*..)
    at com.sun.crypto.provider.RSACipher.engineDoFinal(DashoA13*..)
    at javax.crypto.Cipher.doFinal(DashoA13*..)
    at PKServer.decryptMessage(PKServer.java:36)
    at PKServer.main(PKServer.java:69)
Public-Key Client code:
import java.io.*;
import java.net.*;
import java.security.*;
import javax.crypto.*;

public class PKClient
{
    public static final int kBufferSize = 8192;

    public static void main(String[] args) throws Exception 
    {

        try {           
            // Generate new key
            KeyPair keyPair = KeyPairGenerator.getInstance("RSA").generateKeyPair();
            PrivateKey privateKey = keyPair.getPrivate();
            String message = "The quick brown fox jumps over the lazy dog.";

            // Compute signature
            Signature instance = Signature.getInstance("SHA1withRSA");
            instance.initSign(privateKey);
            instance.update((message).getBytes());
            byte[] signature = instance.sign();

            // Compute digest
            MessageDigest sha1 = MessageDigest.getInstance("SHA1");
            byte[] digest = sha1.digest((message).getBytes());

            // Encrypt digest
            Cipher cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding");
            cipher.init(Cipher.ENCRYPT_MODE, privateKey);
            byte[] encryptedMsg = cipher.doFinal(digest);

            //Store the key in a file
            ObjectOutputStream out = new ObjectOutputStream(new FileOutputStream("KeyFile.xx"));
            out.writeObject(privateKey);
            out.close();

            System.out.println("Client - Message: " + message);
            System.out.println("Client - Encrypted: " + PKServer.asHex(encryptedMsg));

            String host = "localhost";
            int port = 7999;
            Socket s = new Socket(host, port);

            //Open stream to cipher server
            DataOutputStream os = new DataOutputStream(s.getOutputStream());
            os.writeInt(encryptedMsg.length);
            os.write(encryptedMsg);
            os.writeInt(digest.length);
            os.write(digest);
            os.writeInt(signature.length);
            os.write(signature);

            os.flush();
            os.close();

            //Close socket
            s.close();

        }catch (Exception e) {
            e.printStackTrace();
        }
    }
}
Public-key Server code:
import java.io.*;
import java.net.*;
import java.security.*;
import javax.crypto.*;

public class PKServer
{
    public void decryptMessage(InputStream inStream) throws IOException, NoSuchAlgorithmException
    {
        try {

            //Create the Data input stream from the socket
            DataInputStream dis = new DataInputStream(inStream);

            //Get the key
            ObjectInputStream in = new ObjectInputStream(new FileInputStream("KeyFile.xx"));

            //ObjectOutputStream outSocket = new ObjectOutputStream(s.getOutputStream());

            PrivateKey privatekey = (PrivateKey) in.readObject();
            System.out.println("Key Used: " + in.toString());
            in.close();

            //Initiate the cipher
            Cipher cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding");                        
            cipher.init(Cipher.DECRYPT_MODE,privatekey);

            int len = dis.readInt();
            byte[] encryptedMsg = new byte[len];
            dis.readFully(encryptedMsg);         

            System.out.println("Server - Msg Length: " + len);
            System.out.println("Server - Encrypted: " + asHex(encryptedMsg));

            // -Print out the decrypt String to see if it matches the original message.
            byte[] plainText = cipher.doFinal(encryptedMsg);
            System.out.println("Decrypted Message: " + new String(plainText, "SHA"));


        } catch (Exception e) {
            e.printStackTrace();
        }
    }

    //Function to make the bytes printable (hex format)
    public static String asHex(byte buf[]) {
        StringBuilder strbuf = new StringBuilder(buf.length * 2);
        int i;
        for (i = 0; i < buf.length; i++) {
            if (((int) buf[i] & 0xff) < 0x10) {
                strbuf.append("0");
            }
            strbuf.append(Long.toString((int) buf[i] & 0xff, 16));
        }
        return strbuf.toString();
    }
    public static void main(String[] args) throws Exception 
    {
        int port = 7999;
        ServerSocket server = new ServerSocket(port);
        Socket s = server.accept();                     


        PKServer cs = new PKServer();
        cs.decryptMessage(s.getInputStream());

        server.close();
    }
}
Here is the output I receive on the server side:
Key Used: java.io.ObjectInputStream@fee4648
Server - Msg Length: 128
Server - Encrypted: 8c23b2cd96c07950f4901a670b025531b5f52be0730e4548c9a76090d7ae65a8ce82901c66acfb6bd79520cf8d86bf74bf3105fd638892a681a6905556cbadf394915fbdc09babb5b78b9dd06382e92604e9ca88901613520ccb45fcc376e813df059ebc649c52f233dc2632733d99212b42ce54e59ebd6d9dca98af36a20fc6
javax.crypto.BadPaddingException: Data must start with zero
    at sun.security.rsa.RSAPadding.unpadV15(RSAPadding.java:308)
    at sun.security.rsa.RSAPadding.unpad(RSAPadding.java:255)
    at com.sun.crypto.provider.RSACipher.a(DashoA13*..)
    at com.sun.crypto.provider.RSACipher.engineDoFinal(DashoA13*..)
    at javax.crypto.Cipher.doFinal(DashoA13*..)
    at PKServer.decryptMessage(PKServer.java:36)
    at PKServer.main(PKServer.java:69)
I have noticed that if I adjust the line:
Cipher cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding");
to
Cipher cipher = Cipher.getInstance("RSA/ECB/NoPadding");
The program does decrypt but it does not decrypt to the intended string.  It looks like this:
Decrypted Message: E???.1G?:*?$??|o\?"?
V????????O)Z?j??a?!p)6??????_??T*?c?6O????????:?(??C?,??'??`??????(?2D?mC?OLc<7?'?S?R?
Please let me know if you can see where I am going wrong with this code.
解决方案
You need to encrypt your digest with public key in PKClient:
KeyPair keyPair = KeyPairGenerator.getInstance("RSA").generateKeyPair();
Key pubKey = keyPair.getPublic();  // add this
PrivateKey privateKey = keyPair.getPrivate();
// several lines later...
// Initiate the cipher
cipher.init(Cipher.ENCRYPT_MODE, pubKey);  // change privateKey to pubKey


                        
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