no, all strings in an exe can be seen in a hex editor, so your plain text password wouldn't be that safe. but you could encrypt the password too.

encryption could be added quite easily but i don't think it's really necessary. it's a custom format anyway which can't simply be opened with winzip. you could further customize it so that it is more difficult to figure out for other gamestudio users. in the end all encryption is quite useless since with all filepackers your data will land in ram unencrypted anyway and there are plenty of tools for accessing it there.