java 对称加密算法实现详解

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 []http:// 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。

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