目标: 实现字符串移位加密.
缺点: 密钥传输
const DIC =':abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789';
public static function sDecode($s)
{
$sKey ='vjJ3LKNENnrvvRc9HPl5NxRQR5tRrHW';
$a = str_split($s);
$aKey = str_split($sKey);
$iKeyLength = count($aKey);
$aDic = str_split(self::DIC);
$iDicLength = count($aDic);
$kp =0;
$o ='';
foreach ($a as $c) {
$step = ord($aKey[$kp %$iKeyLength]);
$dp =self::ctn($c) -$step;
while ($dp <0) {
$dp +=$iDicLength;
}
// echo $dp . chr(9) . $aDic[$dp] . chr(10);
$o .=$aDic[$dp];
$line = [$c,self::ctn($c),$step,$dp,$aDic[$dp]];
// echo implode(chr(9), $line) . chr(10);
$kp++;
}
return $o;
}
public static function sEncode($s)
{
$sKey ='vjJ3LKNENnrvvRc9HPl5NxRQR5tRrHW';
$a = str_split($s);
$aKey = str_split($sKey);
$iKeyLength = count($aKey);
$aDic = str_split(self::DIC);
$iDicLength = count($aDic);
$kp =0;
$o ='';
foreach ($a as $c) {
$n =self::ctn($c);
$step = ord($aKey[$kp %$iKeyLength]);
// echo $n.chr(9).$step.chr(9).$kp%$iKeyLength.chr(10);
$dp = ($n +$step) %$iDicLength;
$o .=$aDic[$dp];
$kp++;
}
return $o;
}
private static function ctn($c)
{
$aDic = str_split(self::DIC);
$aMap = array_flip($aDic);
return isset($aMap[$c]) ?$aMap[$c] :'|';
}
