具有时效性的php加密解密函数代码

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,8);
$tex=substr($tex,8);
if($verity_str!=substr(md5($tex),8)){
//完整性验证失败
return false;
}
}
$key_b=$type=="decode"?substr($tex,6):$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),8).$reslutstr;
}else{
if(substr($reslutstr,5)!="xugui"){
return false;
}
$reslutstr=substr($reslutstr,5);
}
return $reslutstr;
}
$psa=encode_pass("woshi ceshi yong de ","taintainxousad","encode",120);
echo $psa;
echo "rn解密：";
echo encode_pass($psa,'decode',120);
?>