[Feature] Enter the decryption password during the initrd/boot process

I use a live-usb for quickly running a machine that joins the rest of my homelab) via clustering, and I do not want to hardcode any secrets whatsoever, or any secrets which could simply be extracted from the usb, even if i install things on a ssd, I would like to enter a password on boot or in the initrd phase, to unlock the secrets for nix. I feel like some other people might use this feature, and it allows no secrets to be hardcoded into a system. I used to have a postMountScript which made the secret thing available, but with recent updates this became more complicated, so it being built-in would be useful.