The seed was the hash of the first block seen after the close, so a miner holding tickets
could withhold blocks until one made them win, the active Electrum server could pick which
real block was used by not announcing another (a failed corroboration even moved the draw to
the next block), and the participant order was the server-only `broadcast_at` with no
tie-break, so nobody could recompute the result.
- Open: every round gets a 32-byte `server_seed`, stored only Fernet-encrypted with the
master-xprv key (`server_seed_enc`), with its published `server_seed_hash`;
`draw_confirmations` is copied from round_config. The plaintext column is written only by
the reveal.
- Entering `drawing` (one transaction, `draw_committed` audit row): participants ordered by
bet txid, each `draw_position`, `participants_hash` (sha256 of `txid:vout:address\n`
lines; new `bet_vout`), `draw_height = tip_at_close + 1`. A tip of 0 keeps the round
`closing` (`draw_baseline_tip_unknown`, once per round). All persisted, so a resumed draw
reads rather than recomputes (the `_tick` branch itself is B-81).
- `_complete_draw` / `_wait_for_draw_block` replace `_wait_for_next_block`: wait for
`draw_confirmations` blocks from `draw_height`, then `ElectrumListener.agreed_block_hash`
asks every server, the active one included, for the header at that exact height (valid
work, >= 2 other answers, strict majority of all); no agreement means the same height is
asked again and `draw_header_corroboration_failed` is written once per distinct reported
hash. `draw_stalled` now counts from the last tip advance, or from when the quorum started
to fail. Seed = sha256(server_seed || block_hash || participants_hash), index = seed mod n.
- The winner, the seed and the reveal (`server_seed`, `winner_drawn` payload) are written in
one transaction; a round closing with no participants reveals too. A round opened before
this change (no commitment) is given a secret as it enters `drawing`.
- `GET /rounds/{id}/proof` (public, 404 `round_not_found`, translated in all 7 languages) and
the new fields on `GET /rounds/current`; `draw_confirmations` in `/admin/config` and the
/admin form; `server_seed_hash`/`draw_height` in `/admin/rounds`, never the secret.
- Alembic d3e8b15a7c42 (plain add_column / create_index, expression indexes untouched).
- Docs: the B-73 `*Stato:*`/`*Oggi:*` lines are gone, guides and CLAUDE.md describe the new
draw. Ambiguities resolved in api.md: the proof's participants also carry `amount_sats`
(RND-37 lists it); `seed` is decimal in the proof and hex in the audit row, as specified.
Tests changed because the spec changed: ElectrumListener.corroborate_header (asked only the
other servers about the block the active one announced) is replaced by agreed_block_hash and
its quorum tests ported; draw_winner takes the secret and the list fingerprint; the four
_wait_for_next_block scheduler tests are replaced by _wait_for_draw_block ones (fixed height,
confirmations, same-height retry, stall clock). New: test_draw_proof.py recomputes the winner
independently from the public proof, checks the plaintext secret is nowhere in the database,
the API or the log before the reveal, and that a second pass over a `drawing` round yields
the same winner. Mutation-checked: ordering by broadcast_at, an early reveal and asking the
tip instead of the draw height each fail tests.
Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
PLM Lottery
A periodic-round lottery system built on PLM, a Bitcoin-like coin (mainnet). Each user gets a dedicated server-derived P2WPKH address; they deposit PLM to that address, place a fixed-cost bet to enter the current round, and when the round closes a winner is drawn who receives 70% of the prize pool (the remaining 30% goes to fees).
This is a custodial system: private keys are generated and held server-side, encrypted at rest. See CLAUDE.md for the full architecture, domain decisions, and known gaps before treating this as production-ready.
Quick start
The server always runs via Docker (app + Caddy reverse proxy with automatic
TLS) — in dev and production alike, with only SITE_ADDRESS differing
between the two. There's no supported way to run uvicorn directly; the
venv is only for local tooling (tests, Alembic migrations, the one-time key
scripts) — see CLAUDE.md.
cp .env.example .env # then fill in the generated secrets, see docs/setup.md
mkdir -p data/db data/keys data/logs
docker compose run --rm app python scripts/generate_master_key.py
docker compose up -d --build
Open https://localhost/ for the test UI, https://localhost/admin for the
admin dashboard (a self-signed-certificate warning on first visit is
expected in dev — accept it, or use curl -k). The interactive API docs at
/docs are disabled by default (they'd otherwise expose the whole API
surface, admin endpoints included) — set ENABLE_API_DOCS=true in .env to
enable them.
See docs/setup.md and docs/running-the-server.md for the full walkthrough (secrets, master key generation, production TLS with a real domain).
Documentation
- CLAUDE.md — architecture, commands, domain decisions, known gaps (for anyone/anything working on the code)
- docs/README.md — index of all documentation (docs-first, single source of truth, one ADR per decision: docs/adr/)
- docs/come-funziona.md — the specification (Italian): how the platform works, with diagrams and traceable requirement IDs; it indexes every per-topic document (flows, architecture, data model, API, security, audit log, operations, decisions and limits, bug history). docs/processo-di-modifica.md describes how a change goes from the spec to the code
- docs/setup.md — one-time setup (secrets, master key, migrations)
- docs/running-the-server.md — how to launch it with Docker+Caddy (dev vs. production TLS)
- docs/guida-utente.md — end-user guide to the test UI (Italian)
- docs/guida-admin.md — admin dashboard guide (Italian)
Tech stack
Python (FastAPI, SQLAlchemy async + Alembic, Argon2 + JWT auth), Electrum protocol for PLM network access (no full node), Docker + Caddy for deployment. See CLAUDE.md for the complete list and the reasoning behind each choice.
Testing
python -m pytest # all tests
python -m pytest tests/unit/test_hd.py # one file
617 unit tests cover HD derivation, PSBT building, the Electrum client, bets, deposits, withdrawals, the round/draw engine, RBF fee-bumping, admin config, the pending-inclusive balance calculation, and the SSE push channel. No automated integration tests against a live Electrum connection — mainnet verification so far has been manual (see CLAUDE.md's "Project status").