信息加密之对称加密算法

　　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：

　　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。