为什么我的解密函数不起作用？

Question

这不是我写的；它是由一个传给我的人写的。我和代码的作者失去了联系。我使用这个代码已经有几年了，现在才意识到这个错误。看起来字母序列rkey1弄乱了输出。

例如，turkey1输出与tur79y1一样的解密。这段Perl代码应该输出turkey1，而不是tur79y1

$String = "turkey1";
$e = &encode_escaped(&palace_encrypt($String));
$d = &palace_decrypt(&decode_escaped("'\"".$e."\"'"));
print $d."<br>\n";

KEY REMOVED BY OWNER


sub palace_decrypt
{
    local $lastchar = 0;
    local $rc = 0;
    local @bs;
    for($i=length($_[0])-1; $i>=0; $i--) {
        local $tmp = ord(substr($_[0], $i, 1));
        $bs[$i] = $tmp ^ $palace_key[$rc++] ^ $lastchar;
        $lastchar = $tmp ^ $palace_key[$rc++];
        }

    return join("", map { chr($_) } @bs);
}

sub decode_escaped
{
    $_[0] =~ m/\"(.*)\"/;
    local $str = $1;
    $str =~ s/\\\\/\0/g;
    $str =~ s/\\"/"/g;
    $str =~ s/\\(..)/pack("c",hex($1))/ge;
    $str =~ s/\0/\\/g;
    return $str;
}


sub palace_encrypt
{
    local $lastchar = 0;
    local $rc = 0;
    local @bs;
    for($i=length($_[0])-1; $i>=0; $i--) {
        local $b = ord(substr($_[0], $i, 1));
        $bs[$i] = $b ^ $palace_key[$rc++] ^ $lastchar;
        $lastchar = $bs[$i] ^ $palace_key[$rc++];
        }
    return join("", map { chr($_) } @bs);
}

sub encode_escaped
{
    local $str = $_[0];
    $str =~ s/\\/\\\\/g;
    $str =~ s/([^A-Za-z0-9\.\\])/sprintf("\\%2.2X", ord($1))/ge;

    return $str;
}

Answer 1

你的问题是你的decode_escaped并不能完全撤销encode_escaped所做的事情。用下面的代码替换它，这应该会解决你的问题。

sub decode_escaped
{
    $_[0] =~ m/\"(.*)\"/;
    local @str = split /(\\\\)/, $1;
    foreach (@str) {
        s/\\"/"/g;
        s/\\(..)/chr(hex($1))/ge;
        s/\\\\/\\/;
    }
    return join '', @str;
}