Natively within OS X, I don't know of anything. You can create an archive and password protect it. You can always use PGP to encrypt it, depending on your needs. Given your rather sparse definition of your requirements, it's a difficult question to answer. Now, begin after me: All problem definitions start with a statement of the requirements; if you can't state a definition of your requirements, I can't provide you with a solution set. None of us has all day to ask you 60 questions trying to understand your problem, well at least I don't.