• 0 Posts
  • 15 Comments
Joined 11 months ago
cake
Cake day: September 25th, 2023

help-circle
  • For automatically unlock encrypted drives I followed the approach described in https://michael.stapelberg.ch/posts/2023-10-25-my-all-flash-zfs-network-storage-build/#auto-crypto-unlock

    The password is split half in the server itself and half in a file on the web. During boot the server retrieves the second half via http, concatenates the two halves and use the result to unlock the drive. In this way I can always remove the online key and block the automatic decryption.

    Another approach that I’ve considered was to store the decryption keys on a USB drive connected with a long extension cable. The idea is that if someone will steal your server likely won’t bother to get the cables too.

    TPM is a different beast I didn’t study yet, but my understand is that it protects you in case someone steals your drives or tries to read them from another computer. But as long as they are on your server it will always decrypt them automatically. Therefore you delegate the safety of your data to all the software that starts on boot: your photos may still be fully encrypted at rest so a thief cannot get them out from the disk directly, but if you have an open smb share they can just boot your stolen server and get them out from there





  • I remember this blog post (I cannot find right now) where the person split the decryption password in two: half stored on the server itself and half on a different http server. And there was an init script which downloaded the second half to decrypt the drive. There is a small window of time between when you realize that the server is stolen and when you take off the other half of the password where an attacker could decrypt your data. But if you want to protect from random thieves this should be safe enough as long as the two servers are in different locations and not likely to be stolen toghether.


  • TPM solves a sigthly different threat model: if you dispose the hd or if someone takes it out from your computer it is fully encrypted and safe. But if someone steals your whole server it can start and decrypt the drive. So you have to trust you have good passwords and protection for each service you run. depending on what you want to protect for this is either great solution or sub optimal





  • Yes, you are right, I already use DNS validation. But it is just it is easier to request a single wildcard certificate for my domain and have all the subdomains that I use for the local services defined only in my local DNS. I cannot fully automate the certificate renewal because namecheap requires to allowlist the IP that can call its API, and my ip is dynamic. So renewing a single certificate saves me time. Also, the wildcard certificate is installed on a single machine, so it is not the I increase a lot the attack surface by not having different certificates for each virtual host.