MD5加密不可逆 只能加密，不能解密，代码如下：

package com.ruoyi.common.utils.security; import java.security.MessageDigest; import org.slf4j.Logger; import org.slf4j.LoggerFactory; /**  * Md5加密方法  *  * @author ruoyi  */ public class Md5Utils {
      private static final Logger log = LoggerFactory.getLogger(Md5Utils.class);     private static byte[] md5(String s)     {
          MessageDigest algorithm;         try         {
              algorithm = MessageDigest.getInstance("MD5");             algorithm.reset();             algorithm.update(s.getBytes("UTF-8"));             byte[] messageDigest = algorithm.digest();             return messageDigest;         }         catch (Exception e)         {
              log.error("MD5 Error...", e);         }         return null;     }     private static final String toHex(byte hash[])     {
          if (hash == null)         {
              return null;         }         StringBuffer buf = new StringBuffer(hash.length * 2);         int i;         for (i = 0; i < hash.length; i++)         {
              if ((hash[i] & 0xff) < 0x10)             {
                  buf.append("0");             }             buf.append(Long.toString(hash[i] & 0xff, 16));         }         return buf.toString();     }     public static String hash(String s)     {
          try         {
              return new String(toHex(md5(s)).getBytes("UTF-8"), "UTF-8");         }         catch (Exception e)         {
              log.error("not supported charset...{}", e);             return s;         }     } } AES加密 做AES加密，只能加密，解密时有错： 更多内容参考如下网址  加密时的秘钥只能是16位的 Des加密，加密秘钥必须是8位，参考网址如下：