java 对称加密算法实现详解

前言

对于信息的加密方式多种多样，之前为大家介绍了一种自己设计的加密方式，有兴趣的朋友可以欣赏一下，欢迎给予指点。今天为大家介绍一下对称加密方式，所谓对称加密指的是加密和解密方式呈对称格式，即解密是加密的逆过程，下面我们就看一下：DES、3DES、AES、PBE这四种方式，他们的加密强度依次递增。好吧闲话少说，上代码：

首先我们先看一下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 {
     //获得KEY
     KeyGenerator keyGenerator = KeyGenerator.getInstance("DES");
     keyGenerator.init(56);//设置为默认值56即可
     //获得KEY对象
     SecretKey secrekeyone = keyGenerator.generateKey();
     byte [] byteskey = secrekeyone.getEncoded();

//KEY转换
     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);//设置模式为加密
     byte[] result = cipher.doFinal(src.getBytes());
     System.out.println("jdkEDS:"+result.toString());

//解密
     cipher.init(cipher.DECRYPT_MODE, secerkeytwo);//设置模式为解密
     result = cipher.doFinal(result);
     System.out.println("jdkEDS:"+new String(result));

} catch (Exception e) {
     e.printStackTrace();
   }
 }
}

运行结果：

第二种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 {
     //获得KEY
     KeyGenerator keyGenerator = KeyGenerator.getInstance("DESede");
     //keyGenerator.init(112);//设置密钥长度，默认值为168，也可设置为112
     keyGenerator.init(new SecureRandom());//设置为默认值
     //获得KEY对象
     SecretKey secrekeyone = keyGenerator.generateKey();
     byte [] byteskey = secrekeyone.getEncoded();

//KEY转换
     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);//设置模式为加密
     byte[] result = cipher.doFinal(src.getBytes());
     System.out.println("jdkEDS:"+result.toString());

//解密
     cipher.init(cipher.DECRYPT_MODE, secerkeytwo);//设置模式为解密
     result = cipher.doFinal(result);
     System.out.println("jdkEDS:"+new String(result));

} catch (Exception e) {
     e.printStackTrace();
   }
 }
}

运行结果：

第三种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 {
     //获得key
     KeyGenerator keyGenerator = KeyGenerator.getInstance("AES");
     keyGenerator.init(new SecureRandom());//默认密钥长度为：
     SecretKey secretKey = keyGenerator.generateKey();
     byte [] keyBytes = secretKey.getEncoded();

//key转换
     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();
   }  
 }
}

运行结果：

最后一种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 {
     //初始化盐
     SecureRandom random = new SecureRandom();
     byte [] salt = random.generateSeed(8);

//口令和密钥
     String password = "imooc";
     PBEKeySpec pbeKeySpec = new PBEKeySpec(password.toCharArray());//生成密钥转换对象
     SecretKeyFactory factory = SecretKeyFactory.getInstance("PBEWITHMD5andDES");
     Key key = factory.generateSecret(pbeKeySpec);

//加密
     PBEParameterSpec pbeParameterSpec = new PBEParameterSpec(salt, 100);//实例化PBE对象的一个输入的材料：参数分别为"盐和迭代次数"
     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();
   }
 }
}

运行结果：

结语

对于以上四种方式，PBE是一种较安全的加密方式，对加密起绝定作用的是盐和password，决定着加密的结果。以上即使要为大家介绍的对称加密方式，哪位有更好的方式，还望指教。

来源：https://www.cnblogs.com/AndroidJotting/p/4277766.html