julian
bfe64032d8
Turborepo (pnpm workspaces) with all dependencies pinned to latest mutually-compatible versions: turbo 2.9, TypeScript 6, Fastify 5, React 19, Vite 8, better-sqlite3 12 + Drizzle ORM 0.45. Layout: - apps/server Fastify backend (local JWT auth + role guard, /health) - apps/web React 19 + Vite 8 operator SPA - packages/db Drizzle schema on SQLite/WAL; append-only events + users - packages/devices reader/printer/relay adapter interfaces (intent-only relay) - packages/shared shared domain types Architecture constraints from the design wiki are encoded in the scaffold: append-only hash-chained + signed event log, device-agnostic adapters, "a barrier is not a door" (relay expresses intent only), fully-local offline-first auth. wiki/ is an LLM-maintained Obsidian knowledge base (28 pages) ingested from the architecture & design notes, with its own maintenance schema. Verified: pnpm install, full turbo build (5/5), server boots and serves /health, drizzle-kit generates the initial migration.
30 lines
1.4 KiB
Markdown
30 lines
1.4 KiB
Markdown
---
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type: concept
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tags: [parking, security, crypto, access-control]
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sources: [parking-system-architecture]
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updated: 2026-06-14
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---
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# Challenge–Response Auth (asymmetric signatures)
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The authentication scheme for the [[esp32-custom-controller]]. Closes the actual hole in the
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[[uhppote-udp-protocol]]: **forged or replayed commands**. The requirement is **authenticity +
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freshness (anti-replay)**; encryption is optional. (See [[parking-system-architecture]] §7.)
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```
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Host (private key) ESP32 (host's PUBLIC key only)
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│── "open lane 2" ──────────────────▶│ generates fresh random nonce
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│◀──────────── nonce ─────────────────│
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│ sign(nonce ‖ command ‖ ts) ────────▶│ verify vs stored public key
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│ │ check nonce fresh + unused → pulse relay
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```
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## The elegant property
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The controller stores **only a public key**. Physically compromising the ESP32 (popping the
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cabinet, dumping flash via the [[atecc608]]) yields **nothing usable for forging commands**. The
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fresh per-command **nonce** defeats replay without counter-persistence headaches.
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A shared-secret / encrypted channel would **not** have this property — the secret would sit on
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both ends. That's why authentication (not encryption) is the right build here.
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