java密钥交换算法DH定义与应用实例分析

package com.imooc.security.dh;import java.security.KeyFactory;import java.security.KeyPair;import java.security.KeyPairGenerator;import java.security.PrivateKey;import java.security.PublicKey;import java.security.spec.X509EncodedKeySpec;import javax.crypto.Cipher;import javax.crypto.KeyAgreement;import javax.crypto.SecretKey;import javax.crypto.interfaces.DHPublicKey;import javax.crypto.spec.DHParameterSpec;import org.apache.commons.codec.binary.Base64;//import com.sun.org.apache.xalan.internal.utils.Objects;public class ImoocDH {    private static String src = "cakin24 security dh";    public static void main(String[] args) {        jdkDH();    }    public static void jdkDH() {        try {            //1.初始化发送方密钥            KeyPairGenerator senderKeyPairGenerator = KeyPairGenerator.getInstance("DH");            senderKeyPairGenerator.initialize(512);            KeyPair senderKeyPair = senderKeyPairGenerator.generateKeyPair();            byte[] senderPublicKeyEnc = senderKeyPair.getPublic().getEncoded();//发送方公钥，发送给接收方（网络、文件。。。）            //2.初始化接收方密钥            KeyFactory receiverKeyFactory = KeyFactory.getInstance("DH");            X509EncodedKeySpec x509EncodedKeySpec = new X509EncodedKeySpec(senderPublicKeyEnc);            PublicKey receiverPublicKey = receiverKeyFactory.generatePublic(x509EncodedKeySpec);            DHParameterSpec dhParameterSpec = ((DHPublicKey)receiverPublicKey).getParams();            KeyPairGenerator receiverKeyPairGenerator = KeyPairGenerator.getInstance("DH");            receiverKeyPairGenerator.initialize(dhParameterSpec);            KeyPair receiverKeypair = receiverKeyPairGenerator.generateKeyPair();            PrivateKey receiverPrivateKey = receiverKeypair.getPrivate();            byte[] receiverPublicKeyEnc = receiverKeypair.getPublic().getEncoded();            //3.密钥构建            KeyAgreement receiverKeyAgreement = KeyAgreement.getInstance("DH");            receiverKeyAgreement.init(receiverPrivateKey);            receiverKeyAgreement.doPhase(receiverPublicKey, true);            SecretKey receiverDesKey = receiverKeyAgreement.generateSecret("DES");            KeyFactory senderKeyFactory = KeyFactory.getInstance("DH");            x509EncodedKeySpec = new X509EncodedKeySpec(receiverPublicKeyEnc);            PublicKey senderPublicKey = senderKeyFactory.generatePublic(x509EncodedKeySpec);            KeyAgreement senderKeyAgreement = KeyAgreement.getInstance("DH");            senderKeyAgreement.init(senderKeyPair.getPrivate());            senderKeyAgreement.doPhase(senderPublicKey, true);            SecretKey senderDesKey = senderKeyAgreement.generateSecret("DES");            //if (Objects.equals(receiverDesKey, senderDesKey)) {            if(receiverDesKey.equals(senderDesKey)){                System.out.println("双方密钥相同");            }            //4.加密            Cipher cipher = Cipher.getInstance("DES");            cipher.init(Cipher.ENCRYPT_MODE, senderDesKey);            byte[] result = cipher.doFinal(src.getBytes());            System.out.println("jdk dh encrypt : " + Base64.encodeBase64String(result));            //5.解密            cipher.init(Cipher.DECRYPT_MODE, receiverDesKey);            result = cipher.doFinal(result);            System.out.println("jdk dh decrypt : " + new String(result));        } catch (Exception e) {            e.printStackTrace();        }    }}