This method can only be used in the version of 2016.1 or before. For newer version (probably 2016.2), they changed the encode method. There is no clue for me to decode it.
Open C:\Users\.WebIde100\config\options\webServers.xml Find your FTP and get the encrypted password from the password attribute. Decrypt the password. I have written a PHP script to decrypt the string:
$pwd = "Your encrypted password here.";
$decrypted = '';
while (strlen($pwd) > 0) {
$decrypted .= chr(hexdec(substr($pwd, 0, 4)) ^ hexdec('dfaa'));
$pwd = substr($pwd, 4, strlen($pwd) - 1);
}
echo $decrypted;