julian
4319fb86dc
- dingtian-relay: relay+input controller (4ch on hand). Inputs are decoupled from relays (configurable via input_link_relay) — solves the access-controller-button-flow blocker the UHPPOTE couldn't. Full protocol from the SDK (UDP string control :60001, `00` status parse, input_link_url push, multicast discovery). Driver + hardware test still to build. - dingtian-vs-mqtt: use direct HTTP/UDP now; MQTT skipped (broker = extra infra + failure mode + overkill at one-host/few-devices scale) but kept for later multi-lane scale. - autonomous-direction: record the roadmap to fully unmanned (no booth) and how it reshapes the threat model (operator-fraud -> unattended-machine threats), makes host-in-the-loop entry mandatory, and raises fail-state stakes. - threat-model: note the unmanned shift. index + log. gitignore the vendor SDK (dingtian/, 71MB of binaries/examples) — reference only, protocol captured in the wiki.
44 lines
2.2 KiB
Markdown
44 lines
2.2 KiB
Markdown
---
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type: concept
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tags: [parking, security, foundational]
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sources: [parking-system-architecture]
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updated: 2026-06-14
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---
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# Threat Model
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The **second foundational force** (with [[offline-first]]). The central insight is a
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**reframing of who the adversary is**. (See [[parking-system-architecture]] §3.)
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## The key reframing
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Early thinking focused on protecting the database **at rest** — SQLCipher, LUKS, BitLocker,
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TPM-sealed keys. All of that defends against **an outsider who steals the machine or boots from
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external media**.
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That is the **wrong primary threat**. The most likely adversary is the **legitimate operator at
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the booth**. While the app runs, the database is decrypted in memory and the operator has full
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authorised access *through the app*. Encryption does nothing against the classic parking fraud:
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**take the cash, then void/delete the entry/exit record so the books balance.**
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## Consequences
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The controls that actually address insider/operator fraud are different in kind:
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- **[[append-only-event-chain]]** — events appended, never edited/deleted; a "void" is itself a
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recorded event, hash-chained, and **[[atecc608]]-signed** (unforgeable).
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- **[[reconciliation]]** against an authority the operator can't alter — *this is what remote
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sync really is*: a fraud-control mechanism, not just a backup.
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- **[[disk-os-hardening]]** still worthwhile (defeats boot-from-USB) but **not the main event**;
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with LUKS in place, SQLCipher is optional defence-in-depth.
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The same reframing recurs at the device layer: the [[uhppote-controller]]'s real problem is
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unauthenticated commands ([[uhppote-udp-protocol]]), addressed by detection
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([[event-log-ingestion]]) or prevention ([[esp32-custom-controller]]).
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> **Direction shift:** the system is heading toward **fully unmanned operation** — no operator, no
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> booth ([[autonomous-direction]]). That removes the booth-operator as the *primary* adversary, but
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> swaps in **unattended-machine threats** (tailgating, plate spoofing, physical tampering, forced
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> entry). The append-only signed log + reconciliation controls carry over; the emphasis moves from
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> "catch the cashier" to "trust the automated record and detect tampering."
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