PHP string encryption enhanced version

This article introduces the enhanced version of PHP string encryption, which has certain reference value. Now I share it with everyone. Friends in need can refer to it

• In order to increase Data security

• Avoid multiple encryptions of the same characters to obtain consistent results

• You can set the ciphertext validity period

A custom encryption method is listed below.

How to use

Put Mcrypt.class.php into the class file in your project, and then introduce it through require where you need to use it. If you need to use it more times, In this case, it can be quoted in the parent controller:

Encryption method: Mcrypt::encode($Str, $n);

Decryption method: Mcrypt::decode($Str , $n);

• $Str Required The string that needs to be encrypted and decrypted

• $n Optional The ciphertext validity period, unit s,0 is permanently valid,

  require("Mcrypt.class.php") ;
  $code = Mcrypt::encode('sajkfcasjcla','7580');
  echo "code-".$code;
  
  $code_ans = Mcrypt::decode("$code",'7580');
  echo "answer-".$code_ans;

Mcrypt.class.php

/*
* 字符串加解密类；
* 一次一密；且定时解密有效
* 可用于加密&动态key生成
 */
class Mcrypt{
  public $default_key = 'a!takA:dlmcldEv,e';

/**
 * 字符加密，一次一密,可定时解密有效
 * @param string $string 原文
 * @param string $key 密钥
 * @param int $expiry 密文有效期,单位s,0 为永久有效
 * @return string 加密后的内容
*/
public static function encode($string,$key = '', $expiry = 0){
    $ckeyLength = 4;
    $key = md5($key ? $key : $this->default_key); //解密密匙
    $keya = md5(substr($key, 0, 16));         //做数据完整性验证  
    $keyb = md5(substr($key, 16, 16));         //用于变化生成的密文 (初始化向量IV)
    $keyc = substr(md5(microtime()), - $ckeyLength);
    $cryptkey = $keya . md5($keya . $keyc);  
    $keyLength = strlen($cryptkey);
    $string = sprintf('%010d', $expiry ? $expiry + time() : 0).substr(md5($string . $keyb), 0, 16) . $string;
    $stringLength = strlen($string);

     $rndkey = array();    
     for($i = 0; $i <= 255; $i++) {    
        $rndkey[$i] = ord($cryptkey[$i % $keyLength]);
    }

    $box = range(0, 255);    
    // 打乱密匙簿，增加随机性
    for($j = $i = 0; $i < 256; $i++) {
        $j = ($j + $box[$i] + $rndkey[$i]) % 256;
        $tmp = $box[$i];
        $box[$i] = $box[$j];
        $box[$j] = $tmp;
     }    
     // 加解密，从密匙簿得出密匙进行异或，再转成字符
     $result = &#39;&#39;;
     for($a = $j = $i = 0; $i < $stringLength; $i++) {
        $a = ($a + 1) % 256;
        $j = ($j + $box[$a]) % 256;
        $tmp = $box[$a];
        $box[$a] = $box[$j];
        $box[$j] = $tmp; 
        $result .= chr(ord($string[$i]) ^ ($box[($box[$a] + $box[$j]) % 256]));
      }
     $result = $keyc . str_replace(&#39;=&#39;, &#39;&#39;, base64_encode($result));
     $result = str_replace(array(&#39;+&#39;, &#39;/&#39;, &#39;=&#39;),array(&#39;-&#39;, &#39;_&#39;, &#39;.&#39;), $result);
     return $result;
 }

 /**
 * 字符解密，一次一密,可定时解密有效 
 * @param string $string 密文
 * @param string $key 解密密钥
 * @return string 解密后的内容
 */
 public static function decode($string,$key = &#39;&#39;) {
       $string = str_replace(array(&#39;-&#39;, &#39;_&#39;, &#39;.&#39;),array(&#39;+&#39;, &#39;/&#39;, &#39;=&#39;), $string);
       $ckeyLength = 4;
       $key = md5($key ? $key : $this->default_key); //解密密匙
       $keya = md5(substr($key, 0, 16));         //做数据完整性验证  
       $keyb = md5(substr($key, 16, 16));         //用于变化生成的密文 (初始化向量IV)
       $keyc = substr($string, 0, $ckeyLength);
       $cryptkey = $keya . md5($keya . $keyc);  
       $keyLength = strlen($cryptkey);
       $string = base64_decode(substr($string, $ckeyLength));
       $stringLength = strlen($string);

       $rndkey = array();    
       for($i = 0; $i <= 255; $i++) {    
              $rndkey[$i] = ord($cryptkey[$i % $keyLength]);
        }

        $box = range(0, 255);
        // 打乱密匙簿，增加随机性
        for($j = $i = 0; $i < 256; $i++) {
              $j = ($j + $box[$i] + $rndkey[$i]) % 256;
              $tmp = $box[$i];
              $box[$i] = $box[$j];
              $box[$j] = $tmp;
        }
       // 加解密，从密匙簿得出密匙进行异或，再转成字符
       $result = &#39;&#39;;
       for($a = $j = $i = 0; $i < $stringLength; $i++) {
          $a = ($a + 1) % 256;
          $j = ($j + $box[$a]) % 256;
          $tmp = $box[$a];
          $box[$a] = $box[$j];
          $box[$j] = $tmp; 
          $result .= chr(ord($string[$i]) ^ ($box[($box[$a] + $box[$j]) % 256]));
        }
        if ((substr($result, 0, 10) == 0 || substr($result, 0, 10) - time() > 0)
     && substr($result, 10, 16) == substr(md5(substr($result, 26) . $keyb), 0, 16)
     ) {
         return substr($result, 26);
      } else {
         return &#39;&#39;;
      } 
   }
}

             

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