java 非对称加密算法DH实现详解

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非对称加密算法是相对于对称加密算法来说的，对于对称加密算法请查阅之前的总结，今天为大家介绍一下DH算法，DH是一种密钥交换算法，接收方根据发送方加密时的密钥，生成接收方解密密钥。下面就一起来学习一下吧：

初始化发送方密钥：

KeyPairGenerator sendKeyPairGenerator = KeyPairGenerator.getInstance("DH");
      sendKeyPairGenerator.initialize(512);
      KeyPair sendKeyPair = sendKeyPairGenerator.generateKeyPair();
      byte[] sendPublicKeyEnc = sendKeyPair.getPublic().getEncoded();//生成发送方公钥，发送给接收方（网络、文件...）

初始化接收方密钥：

KeyFactory receiverKeyFactory = KeyFactory.getInstance("DH");
      X509EncodedKeySpec x509EncodedKeySpec = new X509EncodedKeySpec(sendPublicKeyEnc);
      PublicKey receivePublicKey = receiverKeyFactory.generatePublic(x509EncodedKeySpec);
      DHParameterSpec dhParameterSpec = ((DHPublicKey)receivePublicKey).getParams();
      KeyPairGenerator receiverKeyPairGenerator = KeyPairGenerator.getInstance("DH");
      receiverKeyPairGenerator.initialize(dhParameterSpec);
      KeyPair receiverKeyPair = receiverKeyPairGenerator.generateKeyPair();
      PrivateKey receiverPrivateKey = receiverKeyPair.getPrivate();
      byte[] receiverPublicKeyEnc = receiverKeyPair.getPublic().getEncoded();

构建接收方密钥：

KeyAgreement receiverKeyAgreement = KeyAgreement.getInstance("DH");
      receiverKeyAgreement.init(receiverPrivateKey);
      receiverKeyAgreement.doPhase(receivePublicKey, true);
      
      SecretKey receiverDESKey = receiverKeyAgreement.generateSecret("DES");//接收方Key

构建发送方密钥：

KeyFactory sendKeyFactory = KeyFactory.getInstance("DH");
      x509EncodedKeySpec = new X509EncodedKeySpec(receiverPublicKeyEnc);
      PublicKey sendPublicKey = sendKeyFactory.generatePublic(x509EncodedKeySpec);
      
      KeyAgreement sendKeyAgreement = KeyAgreement.getInstance("DH");
      sendKeyAgreement.init(sendKeyPair.getPrivate());
      sendKeyAgreement.doPhase(sendPublicKey, true);
      
      SecretKey sendDESKey = sendKeyAgreement.generateSecret("DES");//发送方Key

发送方加密：

Cipher sendCipher = Cipher.getInstance("DES");
      sendCipher.init(Cipher.ENCRYPT_MODE, sendDESKey);
      byte[] sendResult = sendCipher.doFinal(src.getBytes());
      System.out.println("sendResult ："+Hex.encodeHexString(sendResult));

接收方解密：

Cipher receiverCipher = Cipher.getInstance("DES");
      receiverCipher.init(Cipher.DECRYPT_MODE, receiverDESKey);
      byte[] receiverResult = receiverCipher.doFinal(sendResult);
      System.out.println("receiverResult : "+new String (receiverResult));

基于密钥交换的非对称加密算法（DH）,到这里就总结完毕了。

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