非對稱加密算法是相對于對稱加密算法來說的，對于對稱加密算法請查閱之前的總結(jié)，今天為大家介紹一下DH算法，DH是一種密鑰交換算法，接收方根據(jù)發(fā)送方加密時的密鑰，生成接收方解密密鑰。下面就一起來學(xué)習(xí)一下吧：

初始化發(fā)送方密鑰：

KeyPairGenerator sendKeyPairGenerator = KeyPairGenerator.getInstance("DH");            sendKeyPairGenerator.initialize(512);            KeyPair sendKeyPair = sendKeyPairGenerator.generateKeyPair();            byte[] sendPublicKeyEnc = sendKeyPair.getPublic().getEncoded();//生成發(fā)送方公鑰，發(fā)送給接收方（網(wǎng)絡(luò)、文件...）

初始化接收方密鑰：

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();

構(gòu)建接收方密鑰：

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

構(gòu)建發(fā)送方密鑰：

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");//發(fā)送方Key

發(fā)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));

　　基于密鑰交換的非對稱加密算法（DH）,到這里就總結(jié)完畢了。