---
type: concept
tags: [parking, security, platform]
sources: [parking-system-architecture]
updated: 2026-06-21
---

# Disk / OS Hardening

Worthwhile, but **not the main event** — it defends against the outsider-with-physical-access,
not the operator (see [[threat-model]]). (See [[parking-system-architecture]] §3.)

Physical-access attacks on Windows are trivial (boot media + password-reset tools), so a
**dedicated Linux machine is the correct platform** — not Windows or WSL. This is a
[[standing-decisions|standing decision]].

- **LUKS full-disk encryption** — defeats boot-from-USB.
- **GRUB password + Secure Boot** — prevents boot-parameter tampering / unsigned loaders.
- **No desktop environment** — single-purpose appliance.
- **Key-based SSH only.**
- **[[tpm|TPM 2.0]]** _(recommended, 2026-06-21)_ — seals the LUKS key to the boot chain so the disk
  **auto-unlocks only on an untampered boot**, making encryption-at-rest compatible with **unattended
  reboot** (a booth must come back up after a power cut without a human typing a passphrase). Also a
  candidate home for the non-extractable host event-signing key. Caveats (live-root limit, bus-sniff,
  PCR brittleness, mandatory recovery passphrase + re-seal runbook) on [[tpm]]; implementation is
  [[open-questions]] #12.

With LUKS in place, **SQLCipher becomes optional** defence-in-depth rather than the critical
layer. (The custom controller adds its own: ESP32 flash encryption + secure boot — see
[[esp32-custom-controller]].)

> **Step-by-step OS install + TPM-seal procedure** (BIOS → encrypted install → manual PCR-7 TPM
> seal, with the Dell-7070-specific `dbt` workaround) lives in [[appliance-provisioning]] — written
> from the first real provisioning (2026-06-23) and verified on hardware. **OS hardening on the first
> unit is COMPLETE: LUKS FDE + TPM auto-unlock (PCR 7, unattended) + Secure Boot (Deployed) + GRUB
> edit-lock** (the GRUB password is the specific countermeasure to the `init=/bin/bash` root-shell
> hole that PCR-7 sealing does NOT cover). Resolves the implementation half of [[open-questions]] #12
> for unit 1.

## Deploy-time server configuration (runbook)

Env in `apps/server/.env` on the appliance (see `apps/server/.env.example`). The security-load-bearing ones:

- **`JWT_SECRET`** — ≥32 random chars; the server refuses to boot without a strong one (no
  insecure default). `openssl rand -hex 32`. See [[local-jwt-auth]].
- **`EVENT_SIGNING_KEY`** — dedicated HMAC key for the signed ledger; ≥16 chars. Falls back to
  `JWT_SECRET` with a warning if unset — set a dedicated one before production.
- **`COOKIE_SECURE=0`** — **REQUIRED on the plain-HTTP LAN appliance.** Auth/CSRF cookies are
  `Secure` by **default** (fail-safe). The appliance serves the SPA same-origin over **plain
  http** on the booth LAN, where a `Secure` cookie is **never sent** — so without this opt-out
  **operators cannot log in**. Set it deliberately. (A TLS/reverse-proxied deploy leaves it
  UNSET so cookies stay `Secure`.) This replaced the old `NODE_ENV=production` gate, which
  silently dropped `Secure` if the var was forgotten. See [[local-jwt-auth]].

> The plain-http booth LAN is acceptable because it's an **isolated, single-purpose network**
> (the only browser is the booth's own; access controllers sit on a separate VLAN — see
> [[network-isolation]], [[trust-boundary]]). `Secure`-off is a network-scoped decision, not a
> blanket weakening; the JWT stays HttpOnly + SameSite=Strict and CSRF double-submit still applies.