Dualboot(Windows, OpenBSD) * FDE

[beiroot]

As my Toshiba netbook is sweating its ass off trying to render any webpage under OpenBSD, I decided to switch to something more powerful. I'll be using Lenovo IdeaPad z710. It already has Windows 7 installed with such partitions (picure 2.PNG). The task is to install openbsd without reinstalling windows. I organized some space between the windows partitions, so that OBSD can be on the primary, not on an extended partition (seen in documentation).

My goals are
1. dualboot
2. fde (windows is not encrypted now)

Scenario minimum is nr 1 only. Scenario maximum is 1 and 2.
Now I think I know this can be achieved because I browsed through the forum and looked for some info online, but I just wanted to make sure I have the decent understanding of what my options are.

Regarding dual boot: (picture nr 1.PNG)
1. I could install OpenBSD on fdisk partition nr 3, leave MBR as is and add necessary lines to Windows BCD. Am I correct?
2. I could install OpenBSD on fdisk partition nr 3 and tell MBR that it should boot from this partition. Then install GRUB and add Windows. Am I correct?
...

Regarding encryption:
1. I could install obsd using softraid encryption and use bitlocker on windows. Then I guess depending on the bootloader I choose, I need to provide password in different place? I've read this thread

2. Can I use third party software like Truecrypt, Veracrypt etc take care of the FDE and on-place password typing? I know Truecrypt doesn't support dualboot unless windows BCD is used, right? Other issues is, whether third-party soft will see partitions properly?

Thank you very much for any information/suggestions you have.

[girarde]

TrueCrypt is abandonware whoe developers have recommended against its continued use.

[beiroot]

Yeah, I know the story thoroughly. But only the versions above 7.1a.

[e1-531g]

I have something like:
MBR:
1. Primary partition for Grub2 (ext2 filesystem)
2. Primary partition for Windows (C:\)
3. Primary partition for OpenBSD (softraid)
4. Link to next MBR (they form linkedList-like structure)

Second MBR:
1. NTFS
2. FAT32

I have installed GRUB2 from Debian 8 amd64 Live. See standard iso
here. I don't remember what I typed to install Grub2, but there are plenty of tutorials around the net.

[beiroot]

Thanks, for the info.
I did install OpenBSD with encryption and dualbooting it with Windows.
Something that surprised me though, maybe you guys can explain?

According to the FAQ I need to copy the first 512b from the booting drive (PBR) to a seperate file a point windows to boot from there.
In my case there is a single drive (sd0). The softraid encryption was done, so the proper partitions are on the softraid drive sd2. I thought I needed to copy the first 512b from rsd2a, which contains the root partition. That didn't work. To my surprise, I need to copy pbr from the rsd0a, so the RAID partition. Why?

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My other questions is about the Windows encryption. What would be the best method? I can't user Bitlocker (motherboard/BIOS doesn't support TPM). Should I use VeraCrypt? I've never used it with dualboot. I only used Truecrypt to perform FDE.
Should I encrypt only the system partitions? Can I later encrypt the other windows partitions as well?
Or should I use FDE? How will it affect the existing OBSD partitions?
What about providing the password? It will be before the Windows boot manager, right?
How will it work? Provide password -> select OS. If OBSD -> provide password?
OR:
If windows -> provide password
If OBSD -> press escape -> select Obsd -> provide password?

Sorry for so many detailed questions, but I'm doing a dualboot with encryption for the first time.

[e1-531g]

rsd2a is, from the point of view of BIOS/UEFI, encrypted data. How BIOS would know how to decrypt it to obtain bootloader? It must be unencrypted, so it is and you need to obtain it from rsd0a.

I belive my laptop doesn't have TPM, but I was able to use Bitlocker somehow. Now I don't have Windows encrypted and I don't remember how I did it.