This is an alternative to manually typing your password to decrypt your home server disks.
The idea is that you have a Tang server somewhere on your local network. When your server boots up, it needs to communicate with the Tang server to unlock the disk. Tang doesn’t store the key and is stateless, but the client requires Tang’s cooperation to compute the key.
For me, I’m thinking about someone breaking into my house and stealing my computer. Currently, I have LUKS read a keyfile from a USB drive… but I almost always leave it plugged in… so a thief would probably accidentally steal that too.
With this setup, I’m thinking maybe I could setup a Pi on the opposite side of my house, ideally hidden. And then if my home server gets stolen, LUKS wouldn’t be able to reach my Tang server, and therefore not unlock anything.
The benfit of tang is that you don’t store the secret on a shared server.
The server has a single keypair that it reuses for every client, and each client has thier own keypair.
The encryption key can only be recovered when the client and server perform thier handshake. And only the client gets the key, the server cannot see it.