The shared server-nonce store every signed action consumes (admin login,
first-run setup, self-service erasure). DB-backed so consumption is atomic and
correct under concurrent requests and a future load-balanced fleet:
DELETE FROM challenges WHERE nonce=$1 AND purpose=$2 AND expires_at > NOW()
RETURNING subject
Winning the race returns one row; zero rows = replay/expired/wrong-purpose =>
reject (no TOCTOU). issue_challenge mints a 256-bit nonce bound to a purpose and
optional subject; consume_challenge is the atomic single-use step that pairs with
verify_signed_action (already built, §0.1). Periodic expiry sweep bounds the
table; the table holds no secret and is documented as backup-excluded
(ephemeral, links pubkey->time).
migration 20260625000001; ConsumedChallenge exported; 3 L1 tests (consume-once /
replay-rejected, wrong-purpose rejected, expired rejected).
smirk-backend-core
Open, self-hostable backend for the Smirk non-custodial, multi-chain wallet. It provides the chain-access and identity surface a Smirk wallet needs — authentication, per-chain wallet access (Bitcoin, Litecoin, Monero, Wownero, Grin), the Grin slatepack relay, and Nostr-based identity — so anyone can run their own backend and a Smirk wallet can connect to it.
Status: early, under active development. Interfaces and the database schema may change before the first tagged release. Not yet recommended for production self-hosting.
What it is
- Non-custodial. The server never holds spend keys or seeds. It brokers access to blockchain data and relays wallet-to-wallet messages.
- Open core, feature-flagged. Every feature ships in this codebase and is
toggled per deployment; the wallet reads
GET /api/v1/capabilitiesand adapts to what a given backend offers. - Identity via "Sign in with Smirk". Authentication uses a seed-derived Nostr key (NIP-98); the server stores only public keys.
- Privacy first. No PII is required to use it; operator and user privacy are explicit design goals.
Architecture
Rust + Axum, PostgreSQL via sqlx. The public HTTP contract is generated from the handlers with utoipa (OpenAPI), which in turn drives the wallet's generated TypeScript client — one source of truth, checked for drift in CI.
Quickstart
cp .env.example .env # then fill in DATABASE_URL, JWT_SECRET, node URLs
cargo run # starts the API server
A full self-hosting guide (node requirements, reverse proxy, Tor admin onion,
backups) will live in docs/ as it stabilises.
Security
Please report vulnerabilities privately — see SECURITY.md. Do not open public issues for security reports.
License
To be finalized (MIT vs AGPL-3.0-or-later). Until a LICENSE file is added,
all rights are reserved.