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java密钥交换算法DH定义与应用实例分析

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本文实例讲述了java密钥交换算法DH定义与应用。分享给大家供大家参考,具体如下:

一 对称加密缺点

密钥传递过程复杂,这是对称加密带来的困扰。

二 DH密钥交换算法特点

构建本地密钥
双方密钥一致

三 DH相关参数

四 DH算法实现过程

1、初始化发送方的密钥(KeyPairGenerator、KeyPair、PublicKey)
2、初始化接受方的密钥(KeyFactory、X509EncodedKeySpec、DHPublicKey、DHParameterSpec、KeyPairGenerator、PrivateKey)
3、密钥构建(KeyAgeement、SecretKey、KeyFactory、X509EncodeKeySpec、PublicKey)
4、加密和解密(Cipher)

五 DH代码实现过程

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();
        }
    }
}

六 实现效果

双方密钥相同
jdk dh encrypt : wqnKvpQve05UD64OCQGXcQu5rcssEVSu
jdk dh decrypt : cakin24 security dh

七 应用场景

PS:关于加密解密感兴趣的朋友还可以参考本站在线工具:

文字在线加密解密工具(包含AES、DES、RC4等):
http://tools.softyun.net/password/txt_encode

MD5在线加密工具:
http://tools.softyun.net/password/CreateMD5Password

在线散列/哈希算法加密工具:
http://tools.softyun.net/password/hash_encrypt

在线MD5/hash/SHA-1/SHA-2/SHA-256/SHA-512/SHA-3/RIPEMD-160加密工具:
http://tools.softyun.net/password/hash_md5_sha

在线sha1/sha224/sha256/sha384/sha512加密工具:
http://tools.softyun.net/password/sha_encode

希望本文所述对大家java程序设计有所帮助。

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