Rename 'index.php' to something cryptic, and make it work?

[G2place]

I would like to be able to change the name of the primary "index.php" file,
so something that is quite cryptic, for security reasons.

I did try it, and it does work... somewhat.

But all the links on pages which refer to either the site (logo/header image),
or the main sub-forums link all still refer to "index.php".

I reviewed every file in the system to see where that info is hard-coded.
I changed them all accordingly (only 5 files)... but that even disabled my ability to get into the admincp.
So I reverted them back.

I went into the database, and changed the "forumhome" value in the "setting" table to reflect my cryptic name.
Again, it sort of worked...... but those links mentioned above still linked to "index.php".
So I reverted this db change back.

I want everything on the site that refers/links to the primary "index.php" page,
to reflect the new (cryptic) name I give it.

I won't go into all the security issues/concerns we have.
We just think that this is another feature we would like to have in our arsenal
against hackers.

Any suggestions or help ?

Thanks in Advance