Question

Determining the BIOS-keyboardlayout?

Hi there,

I encrypted my whole system using truecrypt and have entered the password for that in a pre-boot environment without any keyboard drivers loaded, that's where I enter the password every time I boot too.

My problem is, that I can't mount the drive using any other way - when I try to mount it as a encrypted system on a Linux Live CD, Truecrypt keeps telling me the password is wrong. It tried all kinds of different keyboard layouts, none worked.

This of course means, that if my PC ever breaks down and I need to get to the data using a different PC, it won't work.

Now to my question: is there any way to try out the keyboardlayout in this pre-boot, BIOS environment? So I can see which keystroke produces which letter? Is there for example a DOS or Linus Version which doesn't load it's own keyboard drivers before launching a cli?

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Comments
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Clarification Request
Re: password

Does your passwork use only normal letters (a-z, A-Z) and digits (0-9)? Those should be the same on all usual keyboards. It might different if you use other characters.

With encrypted files, we recommend having an unencrypted backup, safely stored.

Kees

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Re:

It does contain special characters too. I have backups.

But I want to be able to mount the disc with e.g. linux too.

So is there a way to try out the bios keyboard layout?

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Answer
NO! Here's why.

The PS/2 connected keyboard and even USB ones send a series of bytes for each make and break of every key.

I think you are thinking if you press the letter A that the letter A is sent. That's not how a PC keyboard works and will astound folk new to the hardware here. Let's find an article so you can catch up on this.

Read http://www.computer-engineering.org/ps2keyboard/ first
Now look at http://www.computer-engineering.org/ps2keyboard/scancodes2.html

That letter A sends the scan code 1C on make and F0, 1C on break and I hope you notice that there is no lower case a.

Something has to decode this to handle upper, lower and the make and break codes. That is some keyboard handler.

Without one, it's gobblygook.
Bob

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Re:

I know that not the printed letter is sent to the computer.

I just hoped there is some way to get to the keyboard layout of the truecrypt level...

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Read your post again.

It appears Truecrypt is working as designed. You'll have to ask them if they plan to support your needs.
Bob

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Answer
Re

I tried every possible keyboardlayout - it just won't work. I'll now decrypt the system (the password does work on boot) and reencrypt it with a new password with less special characters.

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There's a lesson here.

Getting fancy has a price.

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