H9 — Coinjoin input detection¶
Severity: Info · Weight: 0 · Network: No · Positive: Yes
What it detects¶
One or more inputs appear to come from a previous coinjoin transaction, identified by:
- Input value matches a Whirlpool denomination: 100,000 / 1,000,000 / 5,000,000 / 50,000,000 satoshis
- Input UTXO is labelled
coinjoinin the local label store
Effect on scoring¶
H9 is a positive finding — it adds no penalty. When H9 fires:
- H5 (CIOH) is suppressed — a coinjoin-sourced input breaks the common-input-ownership assumption, so penalising for CIOH would be a false positive
- The finding appears green in the UI
Why it matters¶
Spending a coinjoin output is a privacy-positive action — the UTXO's history is broken from its pre-coinjoin chain. Recognising this prevents the scorer from incorrectly penalising coinjoin users.
Whirlpool denominations¶
| Denomination | Sats |
|---|---|
| 0.001 BTC | 100,000 |
| 0.01 BTC | 1,000,000 |
| 0.05 BTC | 5,000,000 |
| 0.5 BTC | 50,000,000 |