# Keys and encryption: do I still need full disk encryption?

A fair question, once you know that Wren Linux keeps your most sensitive files
encrypted on their own: your password database (KeePassXC), the Whonix vault, an
SSH key's passphrase, a GPG key's passphrase. If all of that is already
ciphertext, is full disk encryption (FDE) still worth it?

**Short answer: yes, keep it.** Here is the reasoning, so it is a choice and not a
rule. For the wider picture — tampering, borders, what a thief can really do — see
[opsec.md](opsec.md); for passwords themselves, [passwords.md](passwords.md); for
GPG keys, [gpg.md](gpg.md).

## A login or sudo password does not encrypt anything

It is easy to think "they can't get past my login" or "they don't have my sudo
password." Neither protects a file on the disk:

- Someone with the powered-off laptop **boots it from a USB stick, or takes the
  drive out, and reads the whole disk** — your login and sudo passwords never come
  up. They gate a *live* session, not the bytes on the disk.
- With **autologin** (Wren's default on an encrypted disk), whoever turns the
  laptop on *is you*: they land in your session and read your files. Reading your
  own `~/.ssh`, your configs, your downloads needs **no sudo at all** — sudo only
  guards *root* actions.

So a login/sudo password is not a lock on your data at rest. **Full disk encryption
is the only thing that is.**

## What is actually sensitive on the disk

More than the vault. A working laptop collects, among other things:

- **SSH keys** (e.g. `~/.ssh/`) — including, for a Wren server, the key to your
  VPS.
- **GPG private keys** (`~/.gnupg/`) — and, for whoever signs Wren releases, the
  **release signing key**, the most dangerous key of all: with it, someone can
  sign a fake Wren Linux that your users' machines would trust.
- **Traces:** logs, caches, shell history, the desktop browser's profile, the plain
  fact that you run Tor and Whonix, and the plaintext an amnesic Whonix session
  briefly leaves on disk (deleted, not wiped — host FDE is its backstop).

A private key *with a passphrase* is ciphertext at rest even without FDE, which is
good. But it is not the whole story (next section), and a **passphrase-less key is
plaintext on the disk** — so the first rule is: every private key gets a passphrase.

## Three layers, each for a different job

1. **Per-file encryption** — the passphrase on each key, the app password on each
   vault file. It keeps *that file* unreadable at rest. It does **not** stop someone
   who can change your system.
2. **Full disk encryption** — the blanket over everything at rest, *and* the thing
   that resists **tampering**. Without FDE, someone with brief physical access
   (a border, a hotel, an "evil maid") does not need to read your encrypted files:
   they **alter your unencrypted system** — plant a keylogger — hand it back, and
   capture your vault, wallet and key passphrases the next time you type them. FDE,
   with Secure Boot, is what makes that hard. On Wren, **FDE + autologin is one
   passphrase at boot** and nothing after — one prompt, everything protected.
3. **A hardware security key** (a FIDO2/OpenPGP token) — for the few keys that
   could do the most harm. The private key **never touches the disk**, so booting
   the laptop can't reach it, and a keylogger can't extract it. This is the right
   home for the **release signing key** especially; it matters more there than FDE
   does.

Per-file encryption protects a stolen file. FDE protects everything, and protects
you from tampering. A hardware key protects the crown jewels even from a tampered
machine. They stack; they don't replace each other.

## What to do

- **Keep full disk encryption**, set up at install (the guided "encrypted LVM"
  option; see [install-base.md](install-base.md)). With autologin it costs you one
  passphrase at boot and nothing more.
- **Put a passphrase on every private key** — SSH and GPG alike.
- **Keep the Whonix wallets, messenger and passwords in the vault**, each under its
  own password; host FDE is the layer beneath them.
- **For a release signing key, use a hardware security key**, so it is never on the
  disk at all.

If your machine never leaves a place you fully trust, leaning on the per-file
encryption alone is more defensible. For a laptop that travels, keep FDE: the keys
you most want to protect — your SSH key, your GPG keys — are exactly what tampering
goes after, and FDE is the cheap, one-passphrase defence against it.