php常用加密解密功能函数示例

//加密函数function lock_url($txt,$key=‘www.jb51.net‘){ ?$chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-=+"; ?$nh = rand(0,64); ?$ch = $chars[$nh]; ?$mdKey = md5($key.$ch); ?$mdKey = substr($mdKey,$nh%8, $nh%8+7); ?$txt = base64_encode($txt); ?$tmp = ‘‘; ?$i=0;$j=0;$k = 0; ?for ($i=0; $i<strlen($txt); $i++) { ???$k = $k == strlen($mdKey) ? 0 : $k; ???$j = ($nh+strpos($chars,$txt[$i])+ord($mdKey[$k++]))%64; ???$tmp .= $chars[$j]; ?} ?return urlencode($ch.$tmp);}//解密函数function unlock_url($txt,$key=‘www.jb51.net‘){ ?$txt = urldecode($txt); ?$chars = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-=+"; ?$ch = $txt[0]; ?$nh = strpos($chars,$ch); ?$mdKey = md5($key.$ch); ?$mdKey = substr($mdKey,$nh%8, $nh%8+7); ?$txt = substr($txt,1); ?$tmp = ‘‘; ?$i=0;$j=0; $k = 0; ?for ($i=0; $i<strlen($txt); $i++) { ???$k = $k == strlen($mdKey) ? 0 : $k; ???$j = strpos($chars,$txt[$i])-$nh - ord($mdKey[$k++]); ???while ($j<0) $j+=64; ???$tmp .= $chars[$j]; ?} ?return base64_decode($tmp);}