Java开发实例大全提高篇—

本文主要是介绍Java开发实例大全提高篇——Java安全，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！

开发十年，就只剩下这套架构体系了！ >>>

第6篇 Java安全与Applet应用篇
第20章 Java安全
20.1 Java对称加密
实例531 使用BASE64加密
   public static String encryptBASE64(byte[] data) {
       //加密数据
       return (new BASE64Encoder()).encodeBuffer(data);
   }

   /**
   * 解密
   *
   * @param data
   * @return
   * @throws IOException
   */
   public static byte[] decryptBASE64(String data) throws IOException {
       //解密数据
       return (new BASE64Decoder()).decodeBuffer(data);
   }

   public static void main(String[] avg) throws IOException {
       String data = "明日科技";
       System.out.println("加密前：" + data);
       String data1 = BothBase64.encryptBASE64(data.getBytes());
       System.out.println("加密后：" + data1);
       byte[] data2 = BothBase64.decryptBASE64(data1);
       System.out.println("解密后：" + new String(data2));
   }

实例532 使用BASE64解密
   public static String encryptBASE64(byte[] data) {
       //加密数据
       return (new BASE64Encoder()).encodeBuffer(data);
   }

实例533 生成DES的密钥
   String algorithm = "DES";
   // key保存的文件名称
   String keyFile = "keyData.dat";
   // 数据保存的文件名称
   String dataFile = "fileData.dat";

   public BothDESFile() {
       try {
           initKey();
       } catch (NoSuchAlgorithmException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       }
   }

   /**
   * 生成密钥数据,保存到文件中
   *
   * @throws NoSuchAlgorithmException
   */
   private void initKey() throws NoSuchAlgorithmException {
       // 产生一个随机数源
       SecureRandom secureRandom = new SecureRandom();
       // 为DES算法生成一个KeyGenerator
       KeyGenerator generator = KeyGenerator.getInstance(algorithm);
       generator.init(secureRandom);
       SecretKey key = generator.generateKey();
       //生成密钥数据,保存到文件中
       writeFile(key.getEncoded(), keyFile);

}

   /**
   * 转化密钥成Key进行加密解密
   *
   * @return
   * @throws InvalidKeyException
   * @throws NoSuchAlgorithmException
   * @throws InvalidKeySpecException
   */
   private Key toKey() throws InvalidKeyException, NoSuchAlgorithmException,
           InvalidKeySpecException {
       byte[] key = readFile(keyFile);
       DESKeySpec keySpec = new DESKeySpec(key);
       SecretKeyFactory factory = SecretKeyFactory.getInstance(algorithm);
       SecretKey secretKey = factory.generateSecret(keySpec);
       return secretKey;
   }

   /**
   * 加密，把加密数据保存在文件中
   *
   * @param data
   * @param key
   * @throws InvalidKeyException
   * @throws NoSuchAlgorithmException
   * @throws InvalidKeySpecException
   * @throws NoSuchPaddingException
   * @throws IllegalBlockSizeException
   * @throws BadPaddingException
   */
   public void encrypt(byte[] data) throws InvalidKeyException,
           NoSuchAlgorithmException, InvalidKeySpecException,
           NoSuchPaddingException, IllegalBlockSizeException,
           BadPaddingException {
       Key key = toKey();
       // 使用Cipher实际完成加密操作
       Cipher cipher = Cipher.getInstance(algorithm);
       // 使用密钥初始化Cipher
       cipher.init(Cipher.ENCRYPT_MODE, key);
       byte[] f = cipher.doFinal(data);
       writeFile(f, dataFile);
   }

   /**
   * 解密把数据从文件中取出来在解密
   *
   * @param data
   * @param key
   * @return
   * @throws InvalidKeyException
   * @throws NoSuchAlgorithmException
   * @throws InvalidKeySpecException
   * @throws NoSuchPaddingException
   * @throws IllegalBlockSizeException
   * @throws BadPaddingException
   */
   public String decrypt() throws InvalidKeyException,
           NoSuchAlgorithmException, InvalidKeySpecException,
           NoSuchPaddingException, IllegalBlockSizeException,
           BadPaddingException {
       Key key = toKey();
       Cipher cipher = Cipher.getInstance(algorithm);
       cipher.init(Cipher.DECRYPT_MODE, key);
       byte[] f = readFile(dataFile);
       return new String(cipher.doFinal(f));
   }

       } catch (FileNotFoundException e2) {
           // TODO Auto-generated catch block
           e2.printStackTrace();
       } catch (IOException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       }
   }

   /**
   * 根据fileName读取数据文件
   *
   * @param fileName
   * @return
   */
   public byte[] readFile(String fileName) {

       // 读取
       try {
           File file = new File(fileName);
           FileInputStream fileInputStream = new FileInputStream(file);
           byte[] data = new byte[(int) file.length()];
           fileInputStream.read(data);
           fileInputStream.close();
           return data;
       } catch (FileNotFoundException e1) {
           // TODO Auto-generated catch block
           e1.printStackTrace();
       } catch (IOException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       }
       return null;

}

   public static void main(String[] avg) throws InvalidKeyException, NoSuchAlgorithmException, InvalidKeySpecException, NoSuchPaddingException, IllegalBlockSizeException, BadPaddingException {
       BothDESFile bothDESFile = new BothDESFile();
       String data = "明日科技";

       // 数据加密
       System.out.println("加密前：" + data);
       bothDESFile.encrypt(data.getBytes());

       // 数据解密
       String b = bothDESFile.decrypt();
       System.out.println("解密后：" + b);

}

实例534 使用DES加密
   String algorithm = "DES";
   // key保存的文件名称
   String keyFile = "keyData.dat";
   // 数据保存的文件名称
   String dataFile = "fileData.dat";

   public BothDESFile() {
       try {
           initKey();
       } catch (NoSuchAlgorithmException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       }
   }

}

   /**
   * 根据fileName读取数据文件
   *
   * @param fileName
   * @return
   */
   public byte[] readFile(String fileName) {

}

       // 数据加密
       System.out.println("加密前：" + data);
       bothDESFile.encrypt(data.getBytes());

       // 数据解密
       String b = bothDESFile.decrypt();
       System.out.println("解密后：" + b);

}

实例535 使用DES解密
   String algorithm = "DES";
   // key保存的文件名称
   String keyFile = "keyData.dat";
   // 数据保存的文件名称
   String dataFile = "fileData.dat";

   public BothDESFile() {
       try {
           initKey();
       } catch (NoSuchAlgorithmException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       }
   }

}

   /**
   * 根据fileName读取数据文件
   *
   * @param fileName
   * @return
   */
   public byte[] readFile(String fileName) {

}

       // 数据加密
       System.out.println("加密前：" + data);
       bothDESFile.encrypt(data.getBytes());

       // 数据解密
       String b = bothDESFile.decrypt();
       System.out.println("解密后：" + b);

}

实例536 PBE的盐值
String algorithm = "PBEWithMD5AndDES";

String saltFile = "saltData.dat";
String dataFile = "fileData.dat";

   /**
   * 获取盐值
   *
   * @return
   * @throws Exception
   */
   public void initSalt() {
       byte[] salt = new byte[8];
       Random random = new Random();
       //生成随机数
       random.nextBytes(salt);
       //保存盐值
       writeFile(salt, saltFile);
   }

   /**
   * 获取钥匙
   *
   * @param password
   * @return
   * @throws NoSuchAlgorithmException
   * @throws InvalidKeySpecException
   */
   private Key toKey(String password) throws NoSuchAlgorithmException,
           InvalidKeySpecException {
       PBEKeySpec keySpec = new PBEKeySpec(password.toCharArray());
       SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(algorithm);
       SecretKey secretKey = keyFactory.generateSecret(keySpec);
       return secretKey;
   }

   /**
   * 加密
   *
   * @param data
   * @param password
   * @throws InvalidKeySpecException
   * @throws NoSuchAlgorithmException
   * @throws NoSuchPaddingException
   * @throws InvalidAlgorithmParameterException
   * @throws InvalidKeyException
   * @throws BadPaddingException
   * @throws IllegalBlockSizeException
   */
   public void encrypt(byte[] data, String password)
           throws NoSuchAlgorithmException, InvalidKeySpecException,
           NoSuchPaddingException, InvalidKeyException,
           InvalidAlgorithmParameterException, IllegalBlockSizeException,
           BadPaddingException {
       Key key = toKey(password);
       byte[] salt = readFile(saltFile);
       PBEParameterSpec paramSpec = new PBEParameterSpec(salt, 100);
       Cipher cipher = Cipher.getInstance(algorithm);
       cipher.init(Cipher.ENCRYPT_MODE, key, paramSpec);
       writeFile(cipher.doFinal(data), dataFile);

}

   /**
   * 解密
   *
   * @param data
   * @param password
   * @return
   * @throws InvalidKeySpecException
   * @throws NoSuchAlgorithmException
   * @throws NoSuchPaddingException
   * @throws InvalidAlgorithmParameterException
   * @throws InvalidKeyException
   * @throws BadPaddingException
   * @throws IllegalBlockSizeException
   */
   public String decrypt(String password) throws NoSuchAlgorithmException,
           InvalidKeySpecException, NoSuchPaddingException,
           InvalidKeyException, InvalidAlgorithmParameterException,
           IllegalBlockSizeException, BadPaddingException {
       Key key = toKey(password);
       byte[] salt = readFile(saltFile);
       byte[] data = readFile(dataFile);
       PBEParameterSpec paramSpec = new PBEParameterSpec(salt, 100);
       Cipher cipher = Cipher.getInstance(algorithm);
       cipher.init(Cipher.DECRYPT_MODE, key, paramSpec);
       return new String(cipher.doFinal(data));
   }

   /**
   * 把数据写到指定的文件上
   *
   * @param data
   *            数据
   * @param fileName
   *            文件名称
   */
   public void writeFile(byte[] data, String fileName) {
       try {
           FileOutputStream fileOutputStream = new FileOutputStream(fileName);
           fileOutputStream.write(data);
           fileOutputStream.close();
       } catch (FileNotFoundException e2) {
           // TODO Auto-generated catch block
           e2.printStackTrace();
       } catch (IOException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       }
   }

   /**
   * 根据fileName读取数据文件
   *
   * @param fileName
   * @return
   */
   public byte[] readFile(String fileName) {

}

   public static void main(String[] avg) {
       BothPBEFile bothPBEFile = new BothPBEFile();
       String data = "明日科技";
       String password = "123456";
       System.out.println("加密前：" + data);
       try {
           bothPBEFile.initSalt();
           bothPBEFile.encrypt(data.getBytes(), password);
           String tdata = bothPBEFile.decrypt(password);
           System.out.println("解密后：" + tdata);
       } catch (NoSuchAlgorithmException e) {
           e.printStackTrace();
       } catch (Exception e) {
           e.printStackTrace();
       }
   }

实例537 生成PBE的密钥
String algorithm = "PBEWithMD5AndDES";

String saltFile = "saltData.dat";
String dataFile = "fileData.dat";

}

   /**
   * 根据fileName读取数据文件
   *
   * @param fileName
   * @return
   */
   public byte[] readFile(String fileName) {

}

实例538 使用PBE加密
String algorithm = "PBEWithMD5AndDES";

String saltFile = "saltData.dat";
String dataFile = "fileData.dat";

}

   /**
   * 根据fileName读取数据文件
   *
   * @param fileName
   * @return
   */
   public byte[] readFile(String fileName) {

}

实例539 使用PBE解密
String algorithm = "PBEWithMD5AndDES";

String saltFile = "saltData.dat";
String dataFile = "fileData.dat";

}

   /**
   * 根据fileName读取数据文件
   *
   * @param fileName
   * @return
   */
   public byte[] readFile(String fileName) {

}

20.2 Java非对称加密
实例540 生成RSA密钥对
BothRSAClientFile.java
   private String keyAlgorithm = "RSA";
   private String singAlgorithm = "MD5withRSA";
   // 服务端数据文件
   private String serverdataFile = "fileServerData.dat";
   // 客户端数据文件
   private String clientdataFile = "fileClientData.dat";
   // 签名文件
   private String signdataFile = "fileSignData.dat";
   // 公钥文件
   private String publickeyFile = "keyPublicData.dat";

   /**
   * 根据fileName读取数据文件
   *
   * @param fileName
   * @return
   */
   public byte[] readFile(String fileName) {

}

   /**
   * 校验数字签名
   *
   * @return 校验成功返回true 失败返回false
   */
   public boolean verifySign() {
       byte[] data = readFile(serverdataFile);
       byte[] publicKey = readFile(publickeyFile);
       byte[] sign = readFile(signdataFile);
       X509EncodedKeySpec keySpec = new X509EncodedKeySpec(publicKey);
       KeyFactory keyFactory = null;
       PublicKey pubKey = null;
       try {
           keyFactory = KeyFactory.getInstance(keyAlgorithm);
           pubKey = keyFactory.generatePublic(keySpec);
       } catch (InvalidKeySpecException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       } catch (NoSuchAlgorithmException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       }

       try {
           // 验证签名是否正常
           Signature signature = Signature.getInstance(singAlgorithm);
           signature.initVerify(pubKey);
           signature.update(data);
           return signature.verify(sign);
       } catch (SignatureException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       } catch (InvalidKeyException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       } catch (NoSuchAlgorithmException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       }
       return false;
   }

   /**
   * 用公钥解密
   *
   * @return
   */
   public byte[] decryptByPublicKey() {
       byte[] data = readFile(serverdataFile);
       byte[] key = readFile(publickeyFile);
       // 取得公钥
       X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(key);
       KeyFactory keyFactory = null;
       Key publicKey = null;
       try {
           keyFactory = KeyFactory.getInstance(keyAlgorithm);
           publicKey = keyFactory.generatePublic(x509KeySpec);
       } catch (InvalidKeySpecException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       } catch (NoSuchAlgorithmException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       }

       // 对数据解密
       try {
           Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
           cipher.init(Cipher.DECRYPT_MODE, publicKey);
           return cipher.doFinal(data);
       } catch (NoSuchAlgorithmException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       } catch (NoSuchPaddingException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       } catch (InvalidKeyException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       } catch (IllegalBlockSizeException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       } catch (BadPaddingException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       }
       return null;
   }

   /**
   * 用公钥加密
   */
   public void encryptByPublicKey(byte[] data) {
       byte[] key = readFile(publickeyFile);
       // 取得公钥
       X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(key);
       KeyFactory keyFactory = null;
       Key publicKey = null;
       try {
           keyFactory = KeyFactory.getInstance(keyAlgorithm);
           publicKey = keyFactory.generatePublic(x509KeySpec);
       } catch (InvalidKeySpecException e1) {
           // TODO Auto-generated catch block
           e1.printStackTrace();
       } catch (NoSuchAlgorithmException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       }

       // 对数据加密
       try {
           Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
           cipher.init(Cipher.ENCRYPT_MODE, publicKey);
           writeFile(cipher.doFinal(data), clientdataFile);
       } catch (InvalidKeyException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       } catch (NoSuchAlgorithmException e1) {
           // TODO Auto-generated catch block
           e1.printStackTrace();
       } catch (NoSuchPaddingException e1) {
           // TODO Auto-generated catch block
           e1.printStackTrace();
       } catch (IllegalBlockSizeException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       } catch (BadPaddingException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       }
   }

   public static void main(String[] arg) {
       BothRSAClientFile bothRSAClientFile = new BothRSAClientFile();
       BothRSAServerFile bothRSAServerFile = new BothRSAServerFile();

       String cdata = "服务端你好，这里是客户端";
       bothRSAClientFile.encryptByPublicKey(cdata.getBytes());
       byte [] cdata1 = bothRSAServerFile.decryptByPrivateKey();
       System.out.println("Client原始数据："+cdata);
       System.out.println("Servet解密数据："+new String (cdata1));

   }
BothRSAServerFile.java
   private String keyAlgorithm = "RSA";
   private String singAlgorithm = "MD5withRSA";
   // 服务端数据文件
   private String serverdataFile = "fileServerData.dat";
   // 客户端数据文件
   private String clientdataFile = "fileClientData.dat";
   // 签名文件
   private String signdataFile = "fileSignData.dat";
   // 私钥文件
   private String privatekeyFile = "keyPrivateData.dat";
   // 公钥文件
   private String publickeyFile = "keyPublicData.dat";

   /**
   * 根据fileName读取数据文件
   *
   * @param fileName
   * @return
   */
   public byte[] readFile(String fileName) {

}

   /**
   * 生成密钥对
   */
   public void generateKeyFile() {
       KeyPairGenerator keyPairGen = null;
       try {
           keyPairGen = KeyPairGenerator.getInstance(keyAlgorithm);
       } catch (NoSuchAlgorithmException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       }
       KeyPair keyPair = keyPairGen.generateKeyPair();

       // 公钥
       PublicKey publicKey = keyPair.getPublic();
       writeFile(publicKey.getEncoded(), publickeyFile);

       // 私钥
       PrivateKey privateKey = keyPair.getPrivate();
       writeFile(privateKey.getEncoded(), privatekeyFile);
   }

   /**
   * 用私钥加密
   *
   * @param data
   * @return
   */
   public void encryptByPrivateKey(byte[] data) {

       // 取得私钥
       byte[] key = readFile(privatekeyFile);
       PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(key);
       KeyFactory keyFactory = null;
       Key privateKey = null;
       try {
           keyFactory = KeyFactory.getInstance(keyAlgorithm);
           privateKey = keyFactory.generatePrivate(pkcs8KeySpec);
       } catch (InvalidKeySpecException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       } catch (NoSuchAlgorithmException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       }

       // 对数据加密
       try {
           Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
           cipher.init(Cipher.ENCRYPT_MODE, privateKey);
           writeFile(cipher.doFinal(data), serverdataFile);
       } catch (IllegalBlockSizeException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       } catch (BadPaddingException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       } catch (InvalidKeyException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       } catch (NoSuchAlgorithmException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       } catch (NoSuchPaddingException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       }
   }

   /**
   * 用私钥对信息生成数字签名
   *
   * @param data
   *            加密数据
   * @param privateKey
   *            私钥
   *
   * @return
   * @throws Exception
   */
   public void generateSign() {

       byte[] privateKey = readFile(privatekeyFile);
       byte[] serverData = readFile(serverdataFile);
       // 构造PKCS8EncodedKeySpec对象
       PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(privateKey);

       // KEY_ALGORITHM 指定的加密算法
       KeyFactory keyFactory = null;
       PrivateKey priKey = null;
       try {
           //生成私钥
           keyFactory = KeyFactory.getInstance(keyAlgorithm);
           priKey = keyFactory.generatePrivate(pkcs8KeySpec);
       } catch (InvalidKeySpecException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       } catch (NoSuchAlgorithmException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       }

       try {
           //生成数字签名
           Signature signature = Signature.getInstance(singAlgorithm);
           signature.initSign(priKey);
           signature.update(serverData);
           writeFile(signature.sign(), signdataFile);
       } catch (InvalidKeyException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       } catch (SignatureException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       } catch (NoSuchAlgorithmException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       }
   }

   /**
   * 用私钥解密
   *
   * @param data
   * @param key
   * @return
   * @throws Exception
   */
   public byte[] decryptByPrivateKey() {
       byte[] data = readFile(clientdataFile);
       byte[] key = readFile(privatekeyFile);
       // 取得私钥
       PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(key);
       KeyFactory keyFactory = null;
       Key privateKey = null;
       try {
           keyFactory = KeyFactory.getInstance(keyAlgorithm);
           privateKey = keyFactory.generatePrivate(pkcs8KeySpec);
       } catch (InvalidKeySpecException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       } catch (NoSuchAlgorithmException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       }

       try {
           Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
           cipher.init(Cipher.DECRYPT_MODE, privateKey);
           return cipher.doFinal(data);
       } catch (IllegalBlockSizeException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       } catch (BadPaddingException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       } catch (InvalidKeyException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       } catch (NoSuchAlgorithmException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       } catch (NoSuchPaddingException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       }
       return null;
   }

   public static void main(String[] arg) {
       String data = "客户端你好，我是服务端";
       // 服务端操作
       BothRSAServerFile bothRSAServerFile = new BothRSAServerFile();
       // 生成密钥对
       bothRSAServerFile.generateKeyFile();
       // 加密明文
       bothRSAServerFile.encryptByPrivateKey(data.getBytes());
       // 生成签名
       bothRSAServerFile.generateSign();

// 客户端操作
BothRSAClientFile bothRSAClientFile = new BothRSAClientFile();

       byte[] data1 =null;
       if(bothRSAClientFile.verifySign()){
           data1= bothRSAClientFile.decryptByPublicKey();
       }
       System.out.println("Servet原始数据："+data);
       System.out.println("Client解密数据："+new String (data1));

   }

实例541 使用RSA的签名
BothRSAClientFile.java
   private String keyAlgorithm = "RSA";
   private String singAlgorithm = "MD5withRSA";
   // 服务端数据文件
   private String serverdataFile = "fileServerData.dat";
   // 客户端数据文件
   private String clientdataFile = "fileClientData.dat";
   // 签名文件
   private String signdataFile = "fileSignData.dat";
   // 公钥文件
   private String publickeyFile = "keyPublicData.dat";

   /**
   * 根据fileName读取数据文件
   *
   * @param fileName
   * @return
   */
   public byte[] readFile(String fileName) {

}

   /**
   * 根据fileName读取数据文件
   *
   * @param fileName
   * @return
   */
   public byte[] readFile(String fileName) {

}

       // 公钥
       PublicKey publicKey = keyPair.getPublic();
       writeFile(publicKey.getEncoded(), publickeyFile);

       // 私钥
       PrivateKey privateKey = keyPair.getPrivate();
       writeFile(privateKey.getEncoded(), privatekeyFile);
   }

   /**
   * 用私钥加密
   *
   * @param data
   * @return
   */
   public void encryptByPrivateKey(byte[] data) {

       // KEY_ALGORITHM 指定的加密算法
       KeyFactory keyFactory = null;
       PrivateKey priKey = null;
       try {
           keyFactory = KeyFactory.getInstance(keyAlgorithm);
           priKey = keyFactory.generatePrivate(pkcs8KeySpec);
       } catch (InvalidKeySpecException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       } catch (NoSuchAlgorithmException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       }

       try {
           Signature signature = Signature.getInstance(singAlgorithm);
           signature.initSign(priKey);
           signature.update(serverData);
           writeFile(signature.sign(), signdataFile);
       } catch (InvalidKeyException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       } catch (SignatureException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       } catch (NoSuchAlgorithmException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       }
   }

// 客户端操作
BothRSAClientFile bothRSAClientFile = new BothRSAClientFile();

实例542 RSA服务端加密
BothRSAClientFile.java
   private String keyAlgorithm = "RSA";
   private String singAlgorithm = "MD5withRSA";
   // 服务端数据文件
   private String serverdataFile = "fileServerData.dat";
   // 客户端数据文件
   private String clientdataFile = "fileClientData.dat";
   // 签名文件
   private String signdataFile = "fileSignData.dat";
   // 公钥文件
   private String publickeyFile = "keyPublicData.dat";

   /**
   * 根据fileName读取数据文件
   *
   * @param fileName
   * @return
   */
   public byte[] readFile(String fileName) {

}

   /**
   * 根据fileName读取数据文件
   *
   * @param fileName
   * @return
   */
   public byte[] readFile(String fileName) {

}

       // 公钥
       PublicKey publicKey = keyPair.getPublic();
       writeFile(publicKey.getEncoded(), publickeyFile);

       // 私钥
       PrivateKey privateKey = keyPair.getPrivate();
       writeFile(privateKey.getEncoded(), privatekeyFile);
   }

   /**
   * 用私钥加密
   *
   * @param data
   * @return
   */
   public void encryptByPrivateKey(byte[] data) {

// 客户端操作
BothRSAClientFile bothRSAClientFile = new BothRSAClientFile();

实例543 RSA客户端加密
BothRSAClientFile.java
   private String keyAlgorithm = "RSA";
   private String singAlgorithm = "MD5withRSA";
   // 服务端数据文件
   private String serverdataFile = "fileServerData.dat";
   // 客户端数据文件
   private String clientdataFile = "fileClientData.dat";
   // 签名文件
   private String signdataFile = "fileSignData.dat";
   // 公钥文件
   private String publickeyFile = "keyPublicData.dat";

   /**
   * 根据fileName读取数据文件
   *
   * @param fileName
   * @return
   */
   public byte[] readFile(String fileName) {

}

   /**
   * 根据fileName读取数据文件
   *
   * @param fileName
   * @return
   */
   public byte[] readFile(String fileName) {

}

       // 公钥
       PublicKey publicKey = keyPair.getPublic();
       writeFile(publicKey.getEncoded(), publickeyFile);

       // 私钥
       PrivateKey privateKey = keyPair.getPrivate();
       writeFile(privateKey.getEncoded(), privatekeyFile);
   }

   /**
   * 用私钥加密
   *
   * @param data
   * @return
   */
   public void encryptByPrivateKey(byte[] data) {

// 客户端操作
BothRSAClientFile bothRSAClientFile = new BothRSAClientFile();

实例544 DH服务端加密
BothDHClientFile.java
   private String keyAlgorithm = "DH";
   private String secretAlgorithm = "DES";
   // 服务端数据文件
   private String serverdataFile = "fileServerData.dat";
   // 客户端数据文件
   private String clientdataFile = "fileClientData.dat";
   // 服务端公钥文件
   private String publicServerkeyFile = "keyServerPublicData.dat";
   // 客户端公钥文件
   private String publicClientkeyFile = "keyClientPublicData.dat";
   // 客户端私钥文件
   private String privateClientkeyFile = "keyClientPrivateData.dat";

   /**
   * 根据fileName读取数据文件
   *
   * @param fileName
   * @return
   */
   public byte[] readFile(String fileName) {

}

   /**
   * 生成客户端密钥对
   */
   public void generateClientKeyFile() {
       KeyPairGenerator keyPairGen = null;

       try {
           byte[] publicServerkey = readFile(publicServerkeyFile);
           X509EncodedKeySpec x509EncodedKeySpec = new X509EncodedKeySpec(
                   publicServerkey);
           KeyFactory keyFactory = KeyFactory.getInstance(keyAlgorithm);
           PublicKey publicKey = keyFactory.generatePublic(x509EncodedKeySpec);
           DHParameterSpec dhParameterSpec = ((DHPublicKey) publicKey)
                   .getParams();

           keyPairGen = KeyPairGenerator
                   .getInstance(keyFactory.getAlgorithm());
           keyPairGen.initialize(dhParameterSpec);

       } catch (NoSuchAlgorithmException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       } catch (InvalidKeySpecException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       } catch (InvalidAlgorithmParameterException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       }
       KeyPair keyPair = keyPairGen.generateKeyPair();

       // 公钥
       PublicKey publicKey = keyPair.getPublic();
       writeFile(publicKey.getEncoded(), publicClientkeyFile);

       // 私钥
       PrivateKey privateKey = keyPair.getPrivate();
       writeFile(privateKey.getEncoded(), privateClientkeyFile);
   }

   /**
   * 生成客户端机密密钥
   *
   * @return
   */
   private SecretKey getClientSecretKey() {
       byte[] privateClientKey = readFile(privateClientkeyFile);
       byte[] publicServerKey = readFile(publicServerkeyFile);

       X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(publicServerKey);
       PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(
               privateClientKey);

       PublicKey publicKey = null;
       KeyFactory keyFactory = null;
       Key privateKey = null;
       KeyAgreement keyAgree = null;

       try {
           keyFactory = KeyFactory.getInstance(keyAlgorithm);
           publicKey = keyFactory.generatePublic(x509KeySpec);
           // privateKey = keyFactory.generatePrivate(x509KeySpec);
           privateKey = keyFactory.generatePrivate(pkcs8KeySpec);
           // 创建密钥协议
           keyAgree = KeyAgreement.getInstance(keyFactory.getAlgorithm());
           keyAgree.init(privateKey);
           keyAgree.doPhase(publicKey, true);
           return keyAgree.generateSecret(secretAlgorithm);
       } catch (InvalidKeyException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       } catch (IllegalStateException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       } catch (NoSuchAlgorithmException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       } catch (InvalidKeySpecException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       }
       return null;
   }

   /**
   * 客户端数据解密
   *
   * @param data
   * @param key
   * @return
   * @throws Exception
   */
   public byte[] decryptForClient() {
       SecretKey secretKey = getClientSecretKey();

       try {
           byte[] data = readFile(serverdataFile);
           Cipher cipher = Cipher.getInstance(secretKey.getAlgorithm());
           cipher.init(Cipher.DECRYPT_MODE, secretKey);
           return cipher.doFinal(data);
       } catch (NoSuchAlgorithmException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       } catch (NoSuchPaddingException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       } catch (InvalidKeyException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       } catch (IllegalBlockSizeException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       } catch (BadPaddingException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       }
       return null;
   }

   /**
   * 客户端数据加密
   *
   * @param data
   */
   public void encryptForClient(byte[] data) {

SecretKey secretKey = getClientSecretKey();

       try {
           Cipher cipher = Cipher.getInstance(secretKey.getAlgorithm());
           cipher.init(Cipher.ENCRYPT_MODE, secretKey);
           writeFile(cipher.doFinal(data), clientdataFile);
       } catch (NoSuchAlgorithmException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       } catch (NoSuchPaddingException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       } catch (InvalidKeyException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       } catch (IllegalBlockSizeException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       } catch (BadPaddingException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       }
   }

   public static void main(String[] arg) {
       String data = "服务端你好，我是客户端";
       BothDHServerFile bothDHServerFile = new BothDHServerFile();
       BothDHClientFile bothDHClientFile = new BothDHClientFile();

       // 生成服务端密钥对
       bothDHServerFile.generateServerKeyFile();
       // 生成客户端密钥对
       bothDHClientFile.generateClientKeyFile();
       // 客户端加密
       bothDHClientFile.encryptForClient(data.getBytes());
       // 服务端解密
       byte[] data1 = bothDHServerFile.decryptForServer();
       System.out.println("Client原始数据：" + data);
       System.out.println("Servet解密数据：" + new String(data1));

   }
BothDHServerFile.java
   private String keyAlgorithm = "DH";
   private String secretAlgorithm = "DES";
   // 服务端数据文件
   private String serverdataFile = "fileServerData.dat";
   // 客户端数据文件
   private String clientdataFile = "fileClientData.dat";
   // 服务端私钥文件
   private String privateServerkeyFile = "keyServerPrivateData.dat";
   // 服务端公钥文件
   private String publicServerkeyFile = "keyServerPublicData.dat";
   // 客户端公钥文件
   private String publicClientkeyFile = "keyClientPublicData.dat";

   /**
   * 根据fileName读取数据文件
   *
   * @param fileName
   * @return
   */
   public byte[] readFile(String fileName) {

}

   /**
   * 生成服务端密钥对
   */
   public void generateServerKeyFile() {
       KeyPairGenerator keyPairGen = null;
       try {
           keyPairGen = KeyPairGenerator.getInstance(keyAlgorithm);
       } catch (NoSuchAlgorithmException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       }
       KeyPair keyPair = keyPairGen.generateKeyPair();

       // 公钥
       PublicKey publicKey = keyPair.getPublic();
       writeFile(publicKey.getEncoded(), publicServerkeyFile);

       // 私钥
       PrivateKey privateKey = keyPair.getPrivate();
       writeFile(privateKey.getEncoded(), privateServerkeyFile);
   }

   /**
   * 生成服务端机密密钥
   *
   * @return
   */
   private SecretKey getServerSecretKey() {
       byte[] privateServerKey = readFile(privateServerkeyFile);
       byte[] publicClientKey = readFile(publicClientkeyFile);

       X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(publicClientKey);
       PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(
               privateServerKey);

       Key publicKey = null;
       KeyFactory keyFactory = null;
       Key privateKey = null;
       KeyAgreement keyAgree = null;

       try {
           keyFactory = KeyFactory.getInstance(keyAlgorithm);
           publicKey = keyFactory.generatePublic(x509KeySpec);
           privateKey = keyFactory.generatePrivate(pkcs8KeySpec);
           // 创建密钥协议
           keyAgree = KeyAgreement.getInstance(keyFactory.getAlgorithm());
           //初始化密钥
           keyAgree.init(privateKey);
           keyAgree.doPhase(publicKey, true);
           return keyAgree.generateSecret(secretAlgorithm);
       } catch (InvalidKeyException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       } catch (IllegalStateException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       } catch (NoSuchAlgorithmException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       } catch (InvalidKeySpecException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       }
       return null;
   }

   /**
   * 服务端数据加密
   *
   * @param data
   */
   public void encryptForServer(byte[] data) {

SecretKey secretKey = getServerSecretKey();

       try {
           Cipher cipher = Cipher.getInstance(secretKey.getAlgorithm());
           cipher.init(Cipher.ENCRYPT_MODE, secretKey);
           writeFile(cipher.doFinal(data), serverdataFile);
       } catch (NoSuchAlgorithmException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       } catch (NoSuchPaddingException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       } catch (InvalidKeyException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       } catch (IllegalBlockSizeException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       } catch (BadPaddingException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       }
   }

   /**
   * 服务端数据解密
   *
   * @param data
   * @param key
   * @return
   * @throws Exception
   */
   public byte[] decryptForServer() {
       SecretKey secretKey = getServerSecretKey();

       try {
           byte[] data = readFile(clientdataFile);
           Cipher cipher = Cipher.getInstance(secretKey.getAlgorithm());
           cipher.init(Cipher.DECRYPT_MODE, secretKey);
           return cipher.doFinal(data);
       } catch (NoSuchAlgorithmException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       } catch (NoSuchPaddingException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       } catch (InvalidKeyException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       } catch (IllegalBlockSizeException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       } catch (BadPaddingException e) {
           // TODO Auto-generated catch block
           e.printStackTrace();
       }
       return null;
   }

   public static void main(String[] arg) {
       String data = "客户端你好，我是服务端";
       BothDHServerFile bothDHServerFile = new BothDHServerFile();
       BothDHClientFile bothDHClientFile = new BothDHClientFile();

       // 生成服务端密钥对
       bothDHServerFile.generateServerKeyFile();
       // 生成客户端密钥对
       bothDHClientFile.generateClientKeyFile();
       // 服务端加密
       bothDHServerFile.encryptForServer(data.getBytes());
       // 客户端解密
       byte[] data1 = bothDHClientFile.decryptForClient();
       System.out.println("Servet原始数据：" + data);
       System.out.println("Client解密数据：" + new String(data1));
   }

实例545 DH客户端加密
BothDHClientFile.java
   private String keyAlgorithm = "DH";
   private String secretAlgorithm = "DES";
   // 服务端数据文件
   private String serverdataFile = "fileServerData.dat";
   // 客户端数据文件
   private String clientdataFile = "fileClientData.dat";
   // 服务端公钥文件
   private String publicServerkeyFile = "keyServerPublicData.dat";
   // 客户端公钥文件
   private String publicClientkeyFile = "keyClientPublicData.dat";
   // 客户端私钥文件
   private String privateClientkeyFile = "keyClientPrivateData.dat";