# Establishing the disclosure date (timestamp proof)

## 1. Venue timestamp (primary, authoritative)

The public-disclosure date that matters for prior art is the date your deposit
becomes publicly accessible. Zenodo, TechRxiv/arXiv, the Prior Art Archive, and
Technical Disclosure Commons each stamp and publish that date and (for
Zenodo/preprints) assign a permanent DOI. This is the date examiners and courts
rely on. Record it in `DISCLOSURE_METADATA.md`.

## 2. OpenTimestamps proof (optional, belt-and-suspenders)

`SHA256SUMS.txt` hashes every file in this bundle, so a single timestamp over that
one file cryptographically fixes the whole disclosure. OpenTimestamps anchors that
hash into the Bitcoin blockchain as independent, third-party-verifiable proof:

```bash
pip install opentimestamps-client
cd drum-acoustical-resistor-disclosure
ots stamp SHA256SUMS.txt          # -> SHA256SUMS.txt.ots
# hours later:
ots upgrade SHA256SUMS.txt.ots
ots verify  SHA256SUMS.txt.ots     # reports the block time
```

Keep `SHA256SUMS.txt.ots` next to `SHA256SUMS.txt`. Run `sha256sum -c SHA256SUMS.txt`
to confirm nothing changed before relying on the `.ots`. A dated public Git commit
is a fine alternative.
