On Mon, 21 Sep 1998, Jim Choate wrote:

Forwarded message:

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Date: Tue, 22 Sep 1998 00:46:03 +0000 From: Michael Hohensee <mah248@is9.nyu.edu> Subject: Re: Stego-empty hard drives... (fwd)

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I believe that the idea was to set it up so that BIOS defaults to HD-hiding mode.

How do you propose to do this? Via a BIOS setting?

By default. The machine boots. It is either told to accept a passphrase or is told nothing. If the latter, it boots normally, only with its HD-hiding code. If the former, it prompts, accepts a passphrase, and then boots normally, only with the HD-hiding code disabled. What I think you're asking is how the actual cryptography would be done. I wouldn't want to stick crypto code in the BIOS, or at least not the code which will be used all the time. I think a better way to do this is to have the BIOS boot up in HD-hiding mode all the time, and require user-mode software to disable HD-hiding mode and then deal with the cryptography.

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When you're taking your laptop through customs, you do nothing while the machine boots up, the doctored BIOS does its thing, and everybody's happy. When you want to get at the stuff on the rest of the HD, you reboot and type in your passphrase.

How do you propose to prompt the user for the correct time to type?

You don't, at least not at first. If you hold down maybe the left and right shift keys, in combination with the left alt key while pressing the "R" key, it prompts "BIOS: ". You type your passphrase in. LILO (the LInux LOader) does this if you depress a shift key during boot. Obviously with LILO it's to specify kernel parameters, what OS to boot into, and things like that.