Tudisco 008875a2ad plan(kez-chat): add design doc for the chat + file share project
Pre-implementation planning document for kez-chat — a Keybase-class chat
and file sharing app built on the KEZ stack.

Architecture (no code yet, just the plan):

- Identity: KEZ ed25519 primary keys; handles look like
  @username@kez.lat (placeholder default home server).
- Messaging: NATS broker, dumb relay, clients do E2E with
  ChaCha20-Poly1305 over X25519-derived keys. nkeys-auth means the
  user's KEZ primary key literally IS their NATS credential.
  JetStream handles offline delivery.
- File transfer: Iroh peer-to-peer, content-addressed blobs.
  On-demand fetch (no folder sync, no surprise downloads).
  Shared-files manifest committed via a new sigchain `set_shared_files`
  op; per-entry encryption for private shares.

Server: a single Rust binary `kez-chat-server` that bundles the
handle registry, NATS auth callout, optional sigchain mirror, and
optional Iroh pinning. NATS broker and Iroh node run alongside it.

Includes:
- End-to-end flows (account creation, add contact, send message,
  share file, browse files)
- Proposed folder restructure: pull kez-core + kez-channels out into
  a top-level `rust-lib/` workspace so downstream projects (sig-server,
  chat-server, future) can path-depend cleanly without reaching into
  each other's crate trees
- MVP scope and explicit out-of-scope list
- 7 open design questions with my recommended defaults
- Sequenced build plan (refactor first → server scaffold → NATS auth
  → CLI client → Iroh → manifest → deploy → GUI)
2026-05-24 22:21:03 -06:00

KEZ

KEZ is a portable, decentralized identity graph. It lets a person say:

"These accounts, keys, domains, and identities are all me."

…without depending on any central authority. Every connection is proven by a cryptographic signature against a key the user already controls (a nostr key, an Ed25519 key, etc.), and the proofs are published in places only the claimed account itself can publish to (their gist, their DNS, their nostr relay event). Anyone can verify the graph without trusting a server.

Repository layout

.
├── SPEC.md              ← The protocol. Language-agnostic, normative.
├── rust/                ← Rust implementation (kez-core, kez-channels, kez-cli)
├── nodejs/              ← TypeScript/Node implementation (same shape, same CLI)
├── rust-sig-server/     ← Optional HTTP store for sigchains (axum + SQLite)
├── crosstest.sh         ← Interop test: artifacts move between implementations
└── README.md            ← (this file)

Two parallel implementations. Wire-compatible: a claim signed in Rust verifies in Node and vice versa. The cross-test harness proves it.

A separate rust-sig-server/ crate provides an optional HTTP storage tier for sigchains — useful when a user doesn't want to set up DNS/hosting/nostr, but never required; the protocol stays decentralized.

Documentation

Start here:

  • SPEC.md — the language-agnostic protocol spec (v0.2). Normative for every implementation.
  • rust/README.md — Rust implementation guide: crate layout (kez-core / kez-channels / kez-cli), full CLI reference, channel plugin model, library examples, and the gap list.
  • nodejs/README.md — Node/TypeScript port: same shape as Rust, npm workspaces layout, crypto stack rationale, CLI reference.
  • rust-sig-server/README.md — the optional storage server: API reference, no-auth design + threat model, deployment recipes (bare-metal, Docker, PaaS), and how channel-based publishing remains the fallback if the server is down.

Quick start

Rust

cd rust
cargo build
cargo test                                                # 99 tests
cargo install --path crates/kez-cli                       # → `kez` on PATH
kez verify id github:jason

Full guide: rust/README.md.

Node.js

cd nodejs
npm install
npm test                                                  # 91 tests
npm run cli -- verify id github:jason

Full guide: nodejs/README.md.

Sigchain storage server (optional)

cd rust-sig-server
cargo build --release
./target/release/kez-sig-server                           # listens on :7878

Full guide: rust-sig-server/README.md.

Cross-testing

./crosstest.sh

Runs 19 scenarios that swap implementations at the artifact boundary:

# Scenario
12 nostr-signed JSON claim, both directions
34 nostr-signed compact claim, both directions
56 nostr-signed markdown claim, both directions
78 nostr-signed DNS zone form, both directions
910 ed25519-signed JSON claim, both directions
1112 ed25519-signed compact claim, both directions
1314 ed25519-signed markdown claim, both directions
15 rust builds 3-event nostr sigchain → node parses + shows
16 rust-exported sigchain JSONL == node-exported JSONL (byte-identical)
17 node builds 3-event nostr sigchain → rust parses + shows
18 rust builds ed25519 sigchain → node parses + shows
19 node builds ed25519 sigchain → rust parses + shows

If all 19 pass: JCS canonicalization, both signature suites (BIP-340 Schnorr and Ed25519), the compact kez:z1: zstd+base64url encoding, the Markdown fence, the DNS TXT shape, and the sigchain JSONL bundle format are all byte-compatible across implementations.

Pass -v for verbose output (echoes intermediate commands and proofs).

What ships in v0.2

  • Five channel plugins in each implementation: dns:, github:, nostr:, bluesky:, ap: (alias mastodon:).
  • Four wire encodings: JSON, compact, Markdown fence, DNS TXT.
  • Two primary-key algorithms: nostr/secp256k1 Schnorr (BIP-340) and Ed25519 (RFC 8032).
  • JCS (RFC 8785) canonicalization for everything signed.
  • No API keys required for any channel.

What's not done yet

Tracked in rust/README.md and the spec:

  • verify id consulting the sigchain. Sigchain types, CLI commands (kez sigchain add/revoke/show/export/publish), and the storage server all exist. But proof verification doesn't yet fetch the chain to check for revocations — every verify is still a single one-shot proof check.
  • rotate and add_device sigchain ops.
  • expires_at enforcement during claim verify.
  • Typed VerificationStatus.status reflecting the five failure modes (valid / revoked / expired / unreachable / fork).
  • Auth-required publishers (GitHub gist, Bluesky, ActivityPub).

License

Dual-licensed under MIT or Apache-2.0.

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