B3Note v2: native vetKD, burn-after-reading links, on-chain AI, ic-reactor 4

[b3hr4d]

Summary

A rewrite of B3Note. v1 had security and correctness problems serious enough that patching wasn't practical (see "What v2 fixes" in the README):

• notes were encrypted with keys from DFINITY's unsafe example vetKD canister;
• anyone could overwrite any note;
• Internet Identity users couldn't read their own notes;
• writes to stable-map entries were silently dropped;
• timers stopped after upgrades.

Backend (backend/, Rust)

• ic-cdk 0.20, ic-stable-structures 0.7 and the IC's native vetKD:
  • per-user note keys (b3note/user-key/v1, input = caller);
  • an IBE share key (b3note/share/v1).
• Notes: paginated list_notes, optimistic concurrency (expected_version → Conflict), self-destruct timers, quotas.
• Burn-after-reading share links:
  • an Ed25519 key travels in the URL #fragment, and the reader signs (domain, share id, transport key);
  • opening spends one view, and the view is given back if key derivation fails;
  • replaying the same transport key is refused.
• AI assistant on the IC LLM canister (ai_assist): summarize, title, tags, improve, grammar, shorten, action items, translate, continue, and ask across notes. It has per-user and global hourly budgets and a controller kill switch.
• Safety: rate limits, an inspect_message allow-list, cleanup timers that are re-registered after upgrades, and validated install args.
• backend.did is checked against the code by a unit test (UPDATE_CANDID=1 regenerates it).

Frontend (frontend/)

• Vite 8, React 19, Tailwind v4, TanStack Router and Query, @icp-sdk/* and @icp-sdk/vetkeys.
• ic-reactor 4.0.0-beta.3, pinned exactly:
  • bindings are generated from backend.did into src/canisters/backend.ts (candid-core);
  • one client per tab, borrowed by ReactorProvider;
  • client.queryOptions / mutationOptions with TanStack's own hooks.
• Sign-in (SessionAuth): one AuthLike over Internet Identity and a guest key. The guest key comes with a recovery key that can be exported and imported.
• Encryption:
  • notes are encrypted in the browser with a non-extractable AES-GCM key (cached in IndexedDB), with the note id as associated data;
  • on mainnet, vetKD public keys are pinned against the IC master key.
• App features: Markdown with clickable checklists, tags, pins, search, autosave, conflict resolution, export/import, and account deletion.

Tooling

• icp.yaml (icp-cli 1.6): Rust and asset-canister recipes, a local network with Internet Identity, and a production environment.
• scripts/build-canisters.sh, scripts/test-backend.sh, and frontend/scripts/pocketic-dev.ts for UI work without icp-cli.
• CI (.github/workflows/ci.yml):
  • backend: fmt, clippy, unit and PocketIC tests;
  • frontend: format, typecheck, tests, build, a check that the generated bindings match backend.did, and PicJS against the real canister.
• MIT LICENSE (it was empty).

Testing

• ./scripts/test-backend.sh: 28 Rust unit tests and 30 PocketIC integration tests with real vetKD. The integration tests check keys with the ic-vetkeys crate and use a mock LLM canister.
• pnpm test (frontend): 39 tests. The real crypto runs against a fake vetKD with a known master key; the data layer and sign-in run on ic-reactor's test client.
• pnpm test:pic: 4 tests of the browser code and ic-reactor clients against the real canister in PocketIC.
• Manual browser runs (Playwright), all with no console errors:
  • PocketIC dev setup: notes, checklists, AI actions, Ask, share links and burning, settings, mobile/dark;
  • also on PocketIC: sign-out and restore, recovery-key import on a second browser, edit conflict, saving a shared note, Markdown import, note and account deletion;
  • an icp deploy on a local icp-cli network: guest sign-in, a note, reload, and opening a share link from a fresh browser.
• Not verified: a complete Internet Identity passkey sign-in. The local II window opens at id.ai.localhost:8000/authorize and cancelling is handled, but a headless browser couldn't create the passkey, so this needs a manual check.

Notes for reviewers

• v2 has a new stable-memory layout. Install it as a new canister or reinstall. v1 notes cannot be migrated, because they were encrypted with keys from the insecure demo vetKD canister.
• ic-reactor 4 is a beta. The @ic-reactor/* and @candid-core/* versions are pinned exactly.

🤖 Generated with Claude Code

https://claude.ai/code/session_017mjAwRTxCWYEMCuMXgkyjS

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