收银台数据库存储AES加解密

高级加密标准(AES,Advanced Encryption Standard)为最常见的对称加密算法
加密和解密用到的密钥是相同的，这种加密方式加密速度非常快，适合经常发送数据的场合。缺点是密钥的传输比较麻烦。
加密和解密用的密钥是不同的，这种加密方式是用数学上的难解问题构造的，通常加密解密的速度比较慢，适合偶尔发送数据的场合。优点是密钥传输方便。常见的非对称加密算法为RSA、ECC和EIGamal

/**
* @company xmh
* @version V1.0
*/

package xmh.common.security.aes;

import java.security.Key;
import java.security.SecureRandom;

import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;

import xmh.common.security.base64.Base64Util;

/**
* @ClassName: CashierAesUtils
* @Description: 收银台数据库存储AES加解密

* @date 2015年5月13日下午2:19:53
*/
public class CashierAesUtils {

   private static String keyStr = "xxx";

   private static String charset="utf-8";

   private static Key key = null;

   private static String[] g = new String[4];

   public static String encryptStr(String value){
       String valueSecurity = encodeMessage(value);
       String[] l = new String[4];
       int sum = valueSecurity.length()/4;
       for(int i=0;i<4;i++){
           l[i] = valueSecurity.substring(i*sum, sum*(i+1));
       }
       StringBuffer sb = new StringBuffer();
       for(int i=2;i>=0;i--){
           sb.append(l[i]+g[i]);
       }
       sb.append(g[3] + l[3]);
       return sb.toString();
   }

   public static String decryptStr(String value){
       String[] l = new String[4];
       int sum = value.length()/4;
       for(int i=0;i<4;i++){
           l[i] = value.substring(i*sum, sum*(i+1));
       }
       StringBuffer sb = new StringBuffer();
       for(int i=2;i>=0;i--){
           sb.append(l[i].substring(0, l[i].length()-1));
       }
       value = sb.append(l[3].substring(1, l[3].length())).toString();
       return decodeMessage(value);
   }

   static{
       try {
           KeyGenerator keyGenerator = KeyGenerator.getInstance("AES");
           SecureRandom secureRandom = SecureRandom.getInstance("SHA1PRNG","SUN");
           secureRandom.setSeed(keyStr.getBytes());
           keyGenerator.init(secureRandom);
           key = keyGenerator.generateKey();
           int a = 0;
           for(int i=0;i<4;i++){
               a = i*4;
               if(a>keyStr.length()){
                   a = 0;
               }
               g[i] = String.valueOf(keyStr.charAt(i*4));
           }
       } catch (Exception e) {
           e.printStackTrace();
       }
   }

   private static String encodeMessage(String message){
       String result = null;
       try {
           Cipher cipher = Cipher.getInstance("AES");
           cipher.init(Cipher.ENCRYPT_MODE, key);
           byte[] temp = cipher.doFinal(message.getBytes(charset));
           result = Base64Util.encodeMessage(temp);
       }catch (Exception e) {
           e.printStackTrace();
       }
       return result;
   }
   private static String decodeMessage(String message){
       String result = null;
       try {
           Cipher cipher = Cipher.getInstance("AES");
           cipher.init(Cipher.DECRYPT_MODE, key);
           byte[] temp = cipher.doFinal(Base64Util.decodeMessage(message));
           result = new String(temp,charset);
       }catch (Exception e) {
           e.printStackTrace();
       }
       return result;
   }

}