java 對稱加密算法實現詳解

這篇文章主要介紹了java 對稱加密算法實現詳解,文中通過示例代碼介紹的非常詳細，對大家的學習或者工作具有一定的參考學習價值,需要的朋友可以參考下

前言

對於信息的加密方式多種多樣，之前爲大家介紹了一種自己設計的加密方式，有興趣的朋友可以欣賞一下，歡迎給予指點。今天爲大家介紹一下對稱加密方式，所謂對稱加密指的是加密和解密方式呈對稱格式，即解密是加密的逆過程，下面我們就看一下：DES、3DES、AES、PBE這四種方式，他們的加密強度依次遞增。好吧閒話少說，上代碼：

首先我們先看一下DES：

package cn.edu.hpu.des;

import java.security.Key;

import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESKeySpec;

public class jdk_DES {
  private static final String src = "I Love You !";
  public static void main(String [] args){
    jdk_DES.jdkDES();
  }
  @SuppressWarnings("static-access")
  public static void jdkDES(){
    try {
      //獲得KEY
      KeyGenerator keyGenerator = KeyGenerator.getInstance("DES");
      keyGenerator.init(56);//設置爲默認值56即可
      //獲得KEY對象
      SecretKey secrekeyone = keyGenerator.generateKey();
      byte [] byteskey = secrekeyone.getEncoded();
      
      //KEY轉換
      DESKeySpec deskeyspec = new DESKeySpec(byteskey);
      SecretKeyFactory factory = SecretKeyFactory.getInstance("DES");
      Key secerkeytwo = factory.generateSecret(deskeyspec);
      
      //加密
      Cipher cipher = Cipher.getInstance("DES/ECB/PKCS5Padding");
      cipher.init(cipher.ENCRYPT_MODE, secerkeytwo);//設置模式爲加密
      byte[] result = cipher.doFinal(src.getBytes());
      System.out.println("jdkEDS:"+result.toString());
      
      //解密
      cipher.init(cipher.DECRYPT_MODE, secerkeytwo);//設置模式爲解密
      result = cipher.doFinal(result);
      System.out.println("jdkEDS:"+new String(result));
      
    } catch (Exception e) {
      e.printStackTrace();
    }
  }
}

運行結果：

第二種3重DES:

package cn.edu.hpu.des;

import java.security.Key;
import java.security.SecureRandom;

import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESKeySpec;

public class jdk_3DES {
  private static final String src = "I Love You !";
  public static void main(String [] args){
    jdk_3DES.jdk3DES();
  }
  @SuppressWarnings("static-access")
  public static void jdk3DES(){
    try {
      //獲得KEY
      KeyGenerator keyGenerator = KeyGenerator.getInstance("DESede");
      //keyGenerator.init(112);//設置密鑰長度，默認值爲168，也可設置爲112
      keyGenerator.init(new SecureRandom());//設置爲默認值
      //獲得KEY對象
      SecretKey secrekeyone = keyGenerator.generateKey();
      byte [] byteskey = secrekeyone.getEncoded();
      
      //KEY轉換
      DESKeySpec deskeyspec = new DESKeySpec(byteskey);
      SecretKeyFactory factory = SecretKeyFactory.getInstance("DES");
      Key secerkeytwo = factory.generateSecret(deskeyspec);
      
      //加密
      Cipher cipher = Cipher.getInstance("DES/ECB/PKCS5Padding");
      cipher.init(cipher.ENCRYPT_MODE, secerkeytwo);//設置模式爲加密
      byte[] result = cipher.doFinal(src.getBytes());
      System.out.println("jdkEDS:"+result.toString());
      
      //解密
      cipher.init(cipher.DECRYPT_MODE, secerkeytwo);//設置模式爲解密
      result = cipher.doFinal(result);
      System.out.println("jdkEDS:"+new String(result));
      
    } catch (Exception e) {
      e.printStackTrace();
    }
  }
}

運行結果：

第三種AES:

package cn.edu.hpu.aes;

import java.security.Key;
import java.security.SecureRandom;

import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;

public class jdk_AES {
  private static final String src = "I Love You !";
  public static void main(String [] args){
    AES();
  }
  public static void AES(){
    try {
      //獲得key
      KeyGenerator keyGenerator = KeyGenerator.getInstance("AES");
      keyGenerator.init(new SecureRandom());//默認密鑰長度爲：
      SecretKey secretKey = keyGenerator.generateKey();
      byte [] keyBytes = secretKey.getEncoded();
      
      //key轉換
      Key key = new SecretKeySpec(keyBytes, "AES");
      
      //加密
      Cipher cipher = Cipher.getInstance("AES/ECB/PKCS5Padding");
      cipher.init(Cipher.ENCRYPT_MODE, key);
      byte[] result = cipher.doFinal(src.getBytes());
      System.out.println("AES="+result.toString());
      
      //解密
      cipher.init(Cipher.DECRYPT_MODE, key);
      result = cipher.doFinal(result);
      System.out.println("AES="+new String(result));
      
    } catch (Exception e) {
      e.printStackTrace();
    }  
  }
}

運行結果：

最後一種PBE:

package cn.edu.hpu.pbe;

import java.security.Key;
import java.security.SecureRandom;

import javax.crypto.Cipher;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.PBEKeySpec;
import javax.crypto.spec.PBEParameterSpec;

public class jdk_PBE {
  public static final String src = "I Love You !";
  public static void main(String [] args){
    jdkPBE();
  }
  private static void jdkPBE(){
    try {
      //初始化鹽
      SecureRandom random = new SecureRandom();
      byte [] salt = random.generateSeed(8);
      
      //口令和密鑰
      String password = "imooc";
      PBEKeySpec pbeKeySpec = new PBEKeySpec(password.toCharArray());//生成密鑰轉換對象
      SecretKeyFactory factory = SecretKeyFactory.getInstance("PBEWITHMD5andDES");
      Key key = factory.generateSecret(pbeKeySpec);
      
      //加密
      PBEParameterSpec pbeParameterSpec = new PBEParameterSpec(salt, 100);//實例化PBE對象的一個輸入的材料：參數分別爲"鹽和迭代次數"
      Cipher cipher = Cipher.getInstance("PBEWITHMD5andDES");
      cipher.init(Cipher.ENCRYPT_MODE, key, pbeParameterSpec);
      byte [] result = cipher.doFinal(src.getBytes());
      System.out.println("PBE:"+result.toString());
      
      //解密
      cipher.init(Cipher.DECRYPT_MODE, key, pbeParameterSpec);
      result = cipher.doFinal(result);
      System.out.println("PBE:"+new String(result));
      
    } catch (Exception e) {
      e.printStackTrace();
    }
  }
}

運行結果：

結語

對於以上四種方式，PBE是一種較安全的加密方式，對加密起絕定作用的是鹽和password，決定着加密的結果。以上即使要爲大家介紹的對稱加密方式，哪位有更好的方式，還望指教。

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