具有时效性的 php加密解密函数！

<?php 

function encode_pass($tex,$key,$type="encode",$expiry=0){

    $chrArr=array('a','b','c','d','e','f','g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v','w','x','y','z',

                  'A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z',

                  '0','1','2','3','4','5','6','7','8','9');

    if($type=="decode"){

        if(strlen($tex)<14)return false;

        $verity_str=substr($tex, 0,8);

        $tex=substr($tex, 8);

        if($verity_str!=substr(md5($tex),0,8)){

            //完整性验证失败

            return false;

        }    

    }

    $key_b=$type=="decode"?substr($tex,0,6):$chrArr[rand()%62].$chrArr[rand()%62].$chrArr[rand()%62].$chrArr[rand()%62].$chrArr[rand()%62].$chrArr[rand()%62];

    

    $rand_key=$key_b.$key;    

    //设置时间选项

    $modnum=0;$modCount=0;$modCountStr="";

    if($expiry>0){

        if($type=="decode"){

            $modCountStr=substr($tex,6,1);

            $modCount=$modCountStr=="a"?10:floor($modCountStr);

            $modnum=substr($tex,7,$modCount);

            $rand_key=$rand_key.(floor((time()-$modnum)/$expiry));

        }else{

            $modnum=time()%$expiry;

            $modCount=strlen($modnum);

            $modCountStr=$modCount==10?"a":$modCount;

            

            $rand_key=$rand_key.(floor(time()/$expiry));            

        }

        $tex=$type=="decode"?base64_decode(substr($tex, (7+$modCount))):"xugui".$tex;

    }else{

        $tex=$type=="decode"?base64_decode(substr($tex, 6)):"xugui".$tex;

    }

    $rand_key=md5($rand_key);





    $texlen=strlen($tex);

    $reslutstr="";

    for($i=0;$i<$texlen;$i++){

        $reslutstr.=$tex{$i}^$rand_key{$i%32};

    }

    if($type!="decode"){

        $reslutstr=trim(base64_encode($reslutstr),"==");

        $reslutstr=$modCount?$modCountStr.$modnum.$reslutstr:$reslutstr;

        $reslutstr=$key_b.$reslutstr;

        $reslutstr=substr(md5($reslutstr), 0,8).$reslutstr;

    }else{

        if(substr($reslutstr,0, 5)!="xugui"){

            return false;

        }

        $reslutstr=substr($reslutstr, 5);

    }

    return $reslutstr;

}

$psa=encode_pass("woshi ceshi yong de ","taintainxousad","encode",120);

echo $psa;

echo "\r\n解密：";

echo encode_pass($psa,"taintainxousad",'decode',120);

?> 

该函数具有时效性，只要过期就不能解密！

通过时间动态加密 加密后数据多样化，增加破解难度