How is the firmware password stored on the computer?

How is the firmware password of my iMac actually stored? Where is it stored?

I'm wondering how easy it would be for a software/hardware cracker to compromise the firmware password, if he had access to the physical computer itself.

 

Thanks, but this doesn't really address my actual concern (which I probably should have made more clearer).

Let's say I set my firmware password to "somePasswordThatIAlsoUseInALotOfOtherPlaces".

Is it possible somehow for a hacker to obtain this plain text password from the firmware, if he has physical access to the computer? To understand this, we have to understand how the password is actually stored in the firmware.

 

Thanks for the reply. I should have clarified this better.

Years ago (without thinking much of it) I set the firmware password to be the same password as I use in many other places. Soon, I will be selling the computer. I just want to make sure the new owner won't be able to obtain the password, that's all. I know it's unlikely, but I think it's still worth thinking about.

The questions also arise: Even if I change the firmware password to something else, and then remove the firmware password (obviously I don't want to have a firmware password on a computer that I sell), will that make my original password unrecoverable?