Can some of a new character's BG be secret?

What I mean here is can I have a character with some back story that does not appear in any public forum? I'm not talking about game breaking stuff, here, and obviously I would need GM oversight and approval. I just want to add a little meat to the backstory to come out during roleplay, and as a beneficial side effect, give an enterprising GM some neat stuff to play with should they choose.

I understand exactly what complexities this adds to the GM's life, and realize that I'm a newbie here and as such a potential flight risk from your point of view. So "no" is a completely understandable response, but I have to ask.

No, because the people approving the bio need to have a whole view of the character concept.

You can include things which you state would not be known to the general public, or only by a select few, but everything has to be set out in the profile. It's just so the GMs can find everything, without having to talk to you to get the information.

Quite understandable. Thanks.