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。