每日一得--非对称加密算法之（DH）

一，实现对称加密算法的方式：jdk实现方式

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.Hex;
import com.sun.org.apache.xalan.internal.utils.Objects;


//非对称算法DH
public class DHMain {
private static String str="husq DH test";
/**
* @param args
*/
public static void main(String[] args) {
jdkDH();
}


public static void jdkDH(){
try{
//1 初始化秘钥
KeyPairGenerator senderkeyPairGenerator = KeyPairGenerator.getInstance("DH");
senderkeyPairGenerator.initialize(512);
KeyPair senderKeyPair = senderkeyPairGenerator.generateKeyPair();
byte[] senderPublicKeyEnc = senderKeyPair.getPublic().getEncoded();//发送方秘钥，发送给接收方（网络，文件）

//2 初始化接收方秘钥
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 privateKey = receiverKeyPair.getPrivate();
byte[] receiverPublicKeyEnc = receiverKeyPair.getPublic().getEncoded();

//3 秘钥构建
KeyAgreement receiverKeyAgreement = KeyAgreement.getInstance("DH");
receiverKeyAgreement.init(privateKey);
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)){
System.out.println("双方秘钥相同");
}

//4 加密
Cipher  cipher = Cipher.getInstance("DES");
cipher.init(Cipher.ENCRYPT_MODE, senderDesKey);
byte[] result = cipher.doFinal(str.getBytes());
System.out.println("jdk dh encrypt: "+Hex.encodeHexString(result));


//5 解密
cipher.init(Cipher.DECRYPT_MODE, receiverDesKey);
byte[] nsign = cipher.doFinal(result);
System.out.println("jdk dh decrypt: "+new String(nsign));
}catch(Exception e){
e.printStackTrace();
}
}


}