加密和解密函数

function encrypt($txt)

{

if(empty($txt))

{

return $txt;

exit;

}

$key = C('WKY_KEY');

$chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";

$ikey ="-x6g6ZWm2G9g_vr0Bo.pOq3kRIxsZ6rm";

$nh1 = rand(0,61);

$nh2 = rand(0,61);

$nh3 = rand(0,61);

$ch1 = $chars{$nh1};

$ch2 = $chars{$nh2};

$ch3 = $chars{$nh3};

$nhnum = $nh1 + $nh2 + $nh3;

$knum = 0;$i = 0;

while(isset($key{$i})) $knum +=ord($key{$i++});

$mdKey = substr(md5(md5(md5($key.$ch1).$ch2.$ikey).$ch3),$nhnum%8,$knum%8 + 16);

$txt = base64_encode($txt);

$txt = str_replace(array('+','/','='),array('-','_','.'),$txt);

$tmp = '';

$j=0;$k = 0;

$tlen = strlen($txt);

$klen = strlen($mdKey);

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

$k = $k == $klen ? 0 : $k;

$j = ($nhnum+strpos($chars,$txt{$i})+ord($mdKey{$k++}))%61;

$tmp .= $chars{$j};

}

$tmplen = strlen($tmp);

$tmp = substr_replace($tmp,$ch3,$nh2 % ++$tmplen,0);

$tmp = substr_replace($tmp,$ch2,$nh1 % ++$tmplen,0);

$tmp = substr_replace($tmp,$ch1,$knum % ++$tmplen,0);

return $tmp;

}

/**

* 解密函数

* @param string $txt 需要解密的字符串

* @param string $key 密匙

* @return string 字符串类型的返回结果

*/

function decrypt($txt)

{

if(empty($txt))

{

return $txt;

exit;

}

$key = C('WKY_KEY');

$chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789";

$ikey ="-x6g6ZWm2G9g_vr0Bo.pOq3kRIxsZ6rm";

$knum = 0;$i = 0;

$tlen = strlen($txt);

while(isset($key{$i})) $knum +=ord($key{$i++});

$ch1 = $txt{$knum % $tlen};

$nh1 = strpos($chars,$ch1);

$txt = substr_replace($txt,'',$knum % $tlen--,1);

$ch2 = $txt{$nh1 % $tlen};

$nh2 = strpos($chars,$ch2);

$txt = substr_replace($txt,'',$nh1 % $tlen--,1);

$ch3 = $txt{$nh2 % $tlen};

$nh3 = strpos($chars,$ch3);

$txt = substr_replace($txt,'',$nh2 % $tlen--,1);

$nhnum = $nh1 + $nh2 + $nh3;

$mdKey = substr(md5(md5(md5($key.$ch1).$ch2.$ikey).$ch3),$nhnum % 8,$knum % 8 + 16);

$tmp = '';

$j=0; $k = 0;

$tlen = strlen($txt);

$klen = strlen($mdKey);

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

$k = $k == $klen ? 0 : $k;

$j = strpos($chars,$txt{$i})-$nhnum - ord($mdKey{$k++});

while ($j<0) $j+=61;

$tmp .= $chars{$j};

}

$tmp = str_replace(array('-','_','.'),array('+','/','='),$tmp);

return trim(base64_decode($tmp));

}