Locking Folder

How does a folder lock software actually locks a folder, how does it made a folder totally inaccessible?
I always wonder how does these folder lock softwares does with a folder to make it totally inaccessible to anyone, does they encrypt it, if they , then what changes they made on hard disk?
One folder locking software’s help shows it provides kernel level inaccessibility, how did it achieve that?
Is there anyone to help me out?
It provides use level locking only as far as I know – there are several ways to bypass folder locking- In my opinion if there is content that you have to lock with a Password – I would zip the file with Winzip and set a password there. Either that or if the folder is far too huge to zip then you can always take a double precaution by making it hidden.
It basically sets the attribute to disallow a different user on a different LOGIN from accessing a locked folder however your folder can be accessed by an Admin or someone higher up the hierarchy and anyone who knows your login details.
How to lock a folder