Linux

It's disappointing to see so many commentors arguing against you wanting to do this. Windows has it through bitlocker which is secured via the TPM as you know. Yes it can be bypassed, but it's all about your threat level and effort into mitigating it.

I am currently using a TPM on my opensuse tumbleweed machine to auto unencrypt my drive during boot. What you want to do is possible, but not widely supported (yet). Unfortunately, the best I can do is point you to the section in the opensuse wiki that worked for me.

https://en.opensuse.org/SDB:Encrypted_root_file_system

If you scroll down on that page you'll see the section about TPM support. I don't know how well it will play with your OS. As always, back up all your files before messing with hard drive encryption. Best of luck!

You ended up with full disk encryption. For most people, it's the simple option, everything is encrypted. That means the OS can't start without the key, because you're the only holder of the key. It's both dead simple, and pretty bulletproof since there's no way to access the system without the password. But as you said, not everyone wants that.

What you're asking for is an encrypted home directory. It's not that Linux can't do it, it's just not what you got. Depending on the use case you can either use TPM to unlock the root partition to boot, or not encrypt the system itself. Then when you log in, it decrypts a separate partition (or use ZFS native encryption, or use fscrypt if your filesystem supports it, or use an overlay filesystem like go-cryptfs).

So it's not that Linux doesn't support your use case but rather your distro doesn't offer it as an installation option. From there you either configure it yourself (ArchWiki is great regardless of distro), or seek out a distro that does.

Linux is not an operating system, it's just the kernel. What makes it an OS is what distros build on top of it. Linux alone is not that useful, hence the basis of the GNU+Linux memes: it's Linux, plus a lot of GNU tools to make it do useful things, plus a desktop environment and a whole bunch of other libraries and applications, plus the distro's touch tying it all together in a mostly cohesive experience.

I was kinda annoyed at double password login when I setup my system too. So what I did was just enable automatic login for my user since I’m the only one. I just treat my disk password as my login form so I just enter one password. I still have a user password for things like sudo and other permissions handling when I’m logged in but getting into a new session is automatic on startup so it doesn’t annoy me anymore. Would that work for you?

If you want some more convenience but don't want to give up security, you can use hardware tokens like Nitrokey with GPG.

The process would be generate a random file using dd and /dev/urandom. Set this as the key for FDE. Encrypt it using your GPG and store it on /boot. Have a helper script to ask you plugin your Nitrokey and (optional) pin to decrypt the keyfile to have root decrypted. I had read this on some blog for dm-crypt so you will need to research and adopt to your setup.

Instead of encrypting the entire drive, encrypt the home folder. That way it’s unlocked when you sign in.

Assuming you want:

1. Single password prompt instead of auto-decrypt with tpm
2. User's files to be encrypted

There are several ways to achieve this:

1. autologin (recommended for single user system): / is encrypted using luks or zfs native encryption and user's home needs to be unencrypted. User's password may be same as encryption password for convenience, though they still are two passwords used for different purposes.

2. pam mount: / is unencrypted or auto-decrypted and user's home is encrypted independently from / using zfs,luks,fscrypt,etc. In this case, user's login password must be same as user's home encryption password. It's suitable for multi-user system. NOTE: It cannot be used with autologin since user's home needs to be decrypted to log in.

WARNING: For tpm usage, using secure boot is highly recommended to prevent unauthorized user from accessing key stored in tpm.

To prevent auto-decrypt with tpm, tpm-pin can be used (with autologin for requirement #1).

3. systemd-cryptenroll with/without tpm: As far as I know it can be only used to unlock disk encrypted with luks2. It can be used without tpm with pkcs11-token (e.g. YubiKey) or fido2-device. It also uses parameter encryption while key is unsealed, so safe from key sniffing via communication bus. This is easy if secure boot is enabled and luks2 is used for encryption.

4. clevis with tpm: It can be used in place of systemd-cryptenroll. May be used with zfs native encryption. Though I'm not sure if it uses parameter encryption (correct me).

5. unencrypted keyfile on usb: Not sure about zfs, but you can use keyfile on a usb drive to decrypt luks containers.

NOTE: I'm not a forensic/security expert. I listed a brief overview of methods I could think of to keep user's files encrypted while providing single password till login.

If you want to do away with any protection you have with opting in to a security measure, like typing in a password, why don't you just reinstall and not select the encryption option?

Not requiring a password, or automatically entering a password to decrypt the filesystem, is essentially the same as not having encryption.

Decide which you want: Security or convenience. You cannot have both.

You dont want to do that.

What's the point of encrypting something without a good passphrase? It defeats the whole purpose.

Thats how encryption works. Encryption with TPM protects against removing the drive and reading somewhere else, so I suppose it makes sense for most people.

Linux Distros have this option, Ubuntu has it now I think, but on the others its often manual setup.

Just search for "cryptsetup change to tpm"

Not sure if this works with drive encryption since it comes before the OS, but could this maybe be done with a YubiKey or something like that?

That way, you can plug it in and not worry about typing the password every time, but then it's also secure if someone takes your PC? As long as you remove the key when it's off of course.

https://wiki.archlinux.org/title/Trusted_Platform_Module#Data-at-rest_encryption_with_LUKS

Thats what you want i think

I think people are misunderstanding the whole point of drive encryption. It's so that if the drive is stolen or lost, you don't have to worry about it as much. I personally don't see any benefit in doing this if I have to enter a password every time I plug the damn thing in. If you're concerned about somebody stealing your laptop or desktop, the disk-encryption should be the least of your worries.

To the OC; if you happen to use GNOME, then check out the settings in the DISKS app. It has auto-unlock options in the per-drive settings. I long ago configured it so my USB is auto-unlocked upon being plugged in. Though after several system resets and such whatever I did to do that seems to no longer be visible in the GUI, I know that's how I set it up in the first place.

Linux, booting on zfs? Out of the box? What magic is this

I'm not familiar with zfs, but on an encrypred drive I got around this using crypt tab If i recall. you edit a crypt file, ftab points to it or something...sorry it was 7 years ago. But there is a way to make the OS grab the decryption password. You trade convienience for security obviously

I do not know the answer, but this got me thinking: would it be easier to set up a single login for both session and decryption if /home was on a separate partition and only /home was encrypted?