My password plan makes sense to me but I want to run it by the community to see if there are flaws in my thinking.
I have a laptop running Fedora Workstation and a phone running Graphene. I plan on using KeePassXC and KeePassDX and have the database sync via syncthing when both devices are connected to my local wifi.
I am using a strong diceware passphrase for my LUX encrypted laptop.
Pretty straight forward so far I think. What follows is what I’m curious about.
I plan on using the same diceware passphrase on my phone for the initial unlock.
I plan on using a subset of that passphrase for my Fedora user logon.
I also plan on using a subset of that diceware passphrase for my password manager.
My logic is that my memory of passphrases is only going to be so great and that if I limit the number of passphrases I need to remember (in this case to one) then I can make it a long one. This means that both my devices are powerfully encrypted when turned off.
I feel that I can use subsets of that password for my logon and password manager because they will still be strong and if someone has broken my large passphrase then I can’t expect my logon or password manager passwords to protect me further. The same logic applies to having the same password and my laptop and phone.
Obviously the approach is weakened significantly if it was known that I used this strategy.
Consider the following to make your own life easier:
Same password for Fedora System / LUKS — once the security of LUKS is compromised it makes no difference since people could by pass OS security using usb with another OS, also it will makes the passwords easier to memorize if you type it often.
Better yet: sets things to be unlocked with a key file or a yubico, since LUKS are encrypted with the header and not your password, you can add this key later down the road.
Be aware:
Remember to back up your LUKS header
Remember to actually back up your Keepass database, syncthing doesn’t provided proper backup, bitrot protection or actual redundancy but gives you a false sense of security because you will have your database “saved on multiple devices”
I disagree, because you’ll probably be entering your system and keepass passphrases often, so they might be more susceptible to shoulder surfing (or surveillance cameras?) if you’re not careful where you enter your passwords? Then if the passwords are the same your encryption key is compromised.
Logically, having a long encryption password and using subsets for OS/software password protection makes sense to me…
(Also LUKS is all caps because the S stands for Setup)
I get where you are coming from but If that is a worry, a second method is auth through biometrics or hardware key would be preferred IMO, because if you are using your laptop on public places and someone steals it from you while still turned ON and has your password then the type of encryption at rest that LUKS gives you is worth nothing.
Idk a long password that you barely type will be easier to forget and/or get annoying fast, also Linux has this annoying thing where they make you put the LUKS password and then your system passwords right after signing in.
Thanks Nostradamus and jonah for your valuable input.
I’m not at great risk from shoulder surfing but at the same time it makes sense from a practical perspective to use subsets as I will be typing them a lot. I’ll be typing the LUKS password every day so it will ingrain itself eventually and using the subsets throughout the day will help with that process.
syncthing doesn’t provided proper backup, … actual redundancy
This isn’t true, and its a shame people are constantly saying this, it does provide redundancy, it has built in support for versioning.
Even assuming it didn’t support versioning (which it does), u have the ability to sync files between a myriad of devices, all holding a redundant copy of data as a backup. If something happened to the original copy, you’d recover the data from one of the other devices you had syncthing on. This is assuming you don’t enable auto-sync and rather manually sync files.
but gives you a false sense of security because you will have your database “saved on multiple devices”
Because using auto syncs between devices (the way most people use syncthing) is not proper back up, in case of drive fail/file error/ randomware / deletion, what stops Syncthing of just overriding the files to all other devices?
At that point you will say that you are still safe because of the control version, then your back up system is the control version and not Syncthing.
Personally I would prefer a system that does more than just keeping a diff on the files. There are many other things that could go wrong with it that I don’t feel like going into since they are all over the internet anyways and Syncthing devs themself don’t recommend it for back ups.
I unfortunately have suffered this once, when I added a new device instead of copying the files that I wanted to synchronize to that device the empty folder was propagated to the rest of devices. But to be fair versioning did save me and I was able to recover and sync all devices as intended.
