Implementation example of DES encryption and decryption tool class in Java

This article mainly introduces the DES encryption and decryption tool class implemented in Java, and analyzes the definition and usage of the DES encryption and decryption tool class implemented in Java based on specific examples. Friends in need can refer to this article

The example describes the DES encryption and decryption tool class implemented in Java. I share it with you for your reference. The details are as follows:

A tool class that is very commonly used. I won’t do an in-depth study. Then you can use it directly

DesUtil.java

package lsy;
import java.security.Key;
import java.security.SecureRandom;
import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;
public class DesUtil {
 /**
  * @param args
  */
 public static void main(String[] args) {
  //以下是加密方法algorithm="AES"的测试
  System.out.println(DesUtil.getInstance("lushuaiyin").getEnCodeString("hello"));
  //输出 LDewGAZkmWHeYFjBz56ylw==
  //将上面的密文解密：
  System.out.println(DesUtil.getInstance("lushuaiyin").getDecodeString("LDewGAZkmWHeYFjBz56ylw=="));
  //输出 hello
  //改变密钥测试
  System.out.println(DesUtil.getInstance("suolong").getEnCodeString("hello"));
  //输出 /RLowOJ+Fr3KdMcdJeNatg==
  System.out.println(DesUtil.getInstance("suolong").getDecodeString("/RLowOJ+Fr3KdMcdJeNatg=="));
  //输出 hello
  //如果使用不正确的密钥解密，将会：
  System.out.println(DesUtil.getInstance("suolong").getDecodeString("LDewGAZkmWHeYFjBz56ylw=="));
 }
 private SecretKey key=null;//密钥
 //定义 加密算法,可用 DES,DESede,Blowfish,AES
 //不同的加密方式结果会不同
 private static String algorithm="AES";
 private static DesUtil desUtil=null;
 public DesUtil(){}
 public static DesUtil getInstance(String strKey){
  desUtil=new DesUtil();
  desUtil.createKey(strKey);
  return desUtil;
 }
 /**
  * algorithm 算法
  * @param strKey
  */
 public void createKey(String strKey){
  try{
   KeyGenerator kg=KeyGenerator.getInstance(DesUtil.algorithm);
   byte[] bt=strKey.getBytes("UTF-8");
   SecureRandom sr=new SecureRandom(bt);
   kg.init(sr);
   this.setKey(kg.generateKey());
  }catch(Exception e){
  }
 }
 /**
  * 加密方法，返回密文
  * cipher 密码
  * @param dataStr
  */
 public String getEnCodeString(String dataStr){
  byte[] miwen=null;//密文
  byte[] mingwen=null;//明文
  Cipher cipher;
  String result="";//密文字符串
  try{
   mingwen=dataStr.getBytes("UTF-8");
   cipher=Cipher.getInstance(DesUtil.algorithm);
   cipher.init(Cipher.ENCRYPT_MODE, this.getKey());
   miwen=cipher.doFinal(mingwen);
   BASE64Encoder base64en = new BASE64Encoder();
   result=base64en.encodeBuffer(miwen);//或者可以用下面的方法得到密文，结果是不一样的，都可以正常解密
//   result=byte2hex(miwen);//密文结果类似2C:37:B0:18:06:64:99:61:DE:60:58:C1:CF:9E:B2:97
  }catch(Exception e){
   e.printStackTrace();
  }
  return result;
 }
 /**
  * 解密方法，返回明文
  * @param codeStr
  * @return
  */
 public String getDecodeString(String codeStr){
  BASE64Decoder base64De = new BASE64Decoder();
  byte[] miwen=null;
  byte[] mingwen=null;
  String resultData="";//返回的明文
  Cipher cipher;
  try{
   miwen=base64De.decodeBuffer(codeStr);
   cipher=Cipher.getInstance(DesUtil.algorithm);
   cipher.init(Cipher.DECRYPT_MODE, this.getKey());
   mingwen=cipher.doFinal(miwen);
   resultData = new String(mingwen,"UTF-8");
  }catch(Exception e){
   return "密钥不正确或其他原因导致异常，无法解密！";
  }
  return resultData;
 }
  //二行制转字符串
 public String byte2hex(byte[] b) {
  String hs = "";
  String stmp = "";
  for (int n = 0; n < b.length; n++) {
   stmp = (java.lang.Integer.toHexString(b[n] & 0XFF));
   if (stmp.length() == 1)
    hs = hs + "0" + stmp;
   else
    hs = hs + stmp;
   if (n < b.length - 1)
    hs = hs + ":";
  }
  return hs.toUpperCase();
 }
 public SecretKey getKey() {
  return key;
 }
 public void setKey(SecretKey key) {
  this.key = key;
 }
 public static String getAlgorithm() {
  return algorithm;
 }
 public static void setAlgorithm(String algorithm) {
  algorithm = algorithm;
 }
}

Running results:

LDewGAZkmWHeYFjBz56ylw==
hello
/RLowOJ+Fr3KdMcdJeNatg==
hello
密钥不正确或其他原因导致异常，无法解密！

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