PHP encryption and decryption string functions, _PHP tutorial

PHP encryption and decryption string functions,

PHP encryption and decryption string functions often used in programs

The code is as follows:

/*********************************************************************
    函数名称:encrypt
    函数作用:加密解密字符串
    使用方法:
    加密     :encrypt('str','E','nowamagic');
    解密     :encrypt('被加密过的字符串','D','nowamagic');
    参数说明:
    $string   :需要加密解密的字符串
    $operation:判断是加密还是解密:E:加密   D:解密
    $key      :加密的钥匙(密匙);
    
http://www.cnblogs.com/roucheng/
*********************************************************************/
    function encrypt($string,$operation,$key='')
    {
        $key=md5($key);
        $key_length=strlen($key);
        $string=$operation=='D'?base64_decode($string):substr(md5($string.$key),0,8).$string;
        $string_length=strlen($string);
        $rndkey=$box=array();
        $result='';
        for($i=0;$i<=255;$i++)
        {
            $rndkey[$i]=ord($key[$i%$key_length]);
            $box[$i]=$i;
        }
        for($j=$i=0;$i<256;$i++)
        {
            $j=($j+$box[$i]+$rndkey[$i])%256;
            $tmp=$box[$i];
            $box[$i]=$box[$j];
            $box[$j]=$tmp;
        }
        for($a=$j=$i=0;$i<$string_length;$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($operation=='D')
        {
            if(substr($result,0,8)==substr(md5(substr($result,8).$key),0,8))
            {
                return substr($result,8);
            }
            else
            {
                return'';
            }
        }
        else
        {
            return str_replace('=','',base64_encode($result));
        }
    }

How to use:

$id = 132;
    
$token = encrypt($id, 'E', 'a');
    
echo '加密:'.encrypt($id, 'E', 'a');
echo '<br />';
    
echo '解密：'.encrypt($token, 'D', 'a');

http://www.bkjia.com/PHPjc/1084381.htmlwww.bkjia.comtruehttp: //www.bkjia.com/PHPjc/1084381.htmlTechArticlePHP encryption and decryption string functions. The PHP encryption and decryption string function codes often used in programs are as follows: /* *************************************************** **************** Letter...