Bitlocker understanding

So I use bitlocker on my laptop.
It works fine, but it doesn't have a tpm module, so I just leave a mini usb in one of the usb ports.

It works fine, but I am confused about the security.

So, I understand that if someone installs windows on another drive on the laptop(say usb), and then they try to acess the drive, even with the usb key inserted, it won't work since windows will prompt for the windows password, (or will it ask for the bitlocker recovery key?)

I am more concerned that you can acccess it in Linux.
There is an experimental fuse driver, so you could load up in Linux, will it be able to read the usb key normally and then be able to proceed to read the contents of the drive? (Regardless of the Windows password)

I just want some clarification on exactly how bitlocker works with a usb key inserted all the time.
Thx

The idea is that you keep the USB key in a seperate location. Thus, if your laptop is stolen, they will not have the USB key.

But how does a usb key differ from the tpm module?
I mean, you can't remove the tpm module.

Unless it's a combo of tpm module + bios password, does the usb key have hardware recognition for the motherboard or something?

The TPM module is two things basicaly. It's a hardware cryptography processor that does the hard work of encryption/decryption and it's a secure storage device. The secure storage device requires a number of factors for it to "give up" it's key to OS. A USB drive will give up it's contents to anyone.

Read more here:

Trusted Platform Module - Wikipedia, the free encyclopedia

The idea is that once a key is secured in a TPM, then it cannot be accessed by any reasonable means without the password and/or hardware key (like a smartcard). Thus, if the laptop is stolen, nobody can access the key.

Gothca, that's kind of anoyying to remove a usb drive nonstop.

Still, if I just left the usb drive plugged in all the time, would I be protected if you tried to load up windows on another drive?
Like would it ask for my bitlocker recovery key, or just straight read it from the usb drive w/o issue? I could probably try it myself, but that's a bit of work.

I mean I realize that you can probably access it via Linux, but I don't think your average joe would even bother.

Linux won't be able to read it, because the data on the drive is encrypted. I don't know of any software in Linux that can decrypt a bitlocker drive even if you have the key.

The way I use bitlocker is to save the recovery key to a usb drive, then hide the usb drive. Then you only use the password to access the drive.