信息加密之非对称加密DH算法

　　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。