It's the same from both sides (except for the screws, you can only unscrew it from the inside). Both the inside and the outside have a keyhole, and while a key is in one side you can't put a key in all the way from the other side (this way you can lock from the inside, leave the key in, and even someone with the key can't get in).

Normally people don't lock the door while they are inside (maybe at night), on doors facing outside the door handle can't be turned from the outside and you have to use the key to get inside even when the door isn't locked.