Git OpenTimestamp Hook

Automatically generate OpenTimestamp proofs for git commits with full Bitcoin attestation.

⚠️ Requirements

Required: opentimestamps-client (ots CLI)

pipx install opentimestamps-client

Note: The Node.js @opentimestamps/ots package is not supported - it only creates local proofs without calendar submission or Bitcoin attestation. For tamper-evident timestamps, you must use the Python opentimestamps-client.

Quick Install

# Clone this repository
git clone <repository-url>
cd git-ots-hook

# Install hooks (requires ots CLI)
./hooks/install.sh /path/to/your/repo

# Commit the proofs
cd /path/to/your/repo
git add .ots/
git commit -m "Add OpenTimestamp proofs"

That's it! Every commit will now be timestamped and anchored to Bitcoin.

Manual Installation

# Copy hooks
cp hooks/post-commit .git/hooks/post-commit
cp hooks/pre-commit .git/hooks/pre-commit
chmod +x .git/hooks/post-commit .git/hooks/pre-commit

# Setup .gitignore
echo ".ots/.attestation-cache" >> .gitignore

What You Get

• Automatic timestamping - Every commit gets a cryptographic proof
• Bitcoin attestation - Proofs anchored to Bitcoin blockchain (~10 min)
• Full history - Backfill hook upgrades all historical commits
• Smart caching - Minimal network overhead after initial setup
• Tamper-evident - Anyone can verify your commit history

Generated Files

repo/
├── .ots/
│   ├── <commit-hash>.ots   # Individual proof (commit this)
│   ├── proof.ots           # Latest proof (commit this)
│   ├── prev-commit.txt     # Chain link (commit this)
│   ├── commit-chain.txt    # Full chain (commit this)
│   └── .attestation-cache  # Local cache (ignore this)
└── ...

Verification

Check a proof:

ots info .ots/<commit-hash>.ots

Verify attestation:

ots verify .ots/<commit-hash>.ots

Upgrade pending proofs:

ots upgrade .ots/<commit-hash>.ots

How It Works

1. You make a git commit
2. Post-commit hook extracts commit hash
3. Hash submitted to 4+ remote calendar servers
4. Calendars aggregate and anchor to Bitcoin
5. After ~10 min: proof becomes Bitcoin-attested
6. Pre-commit hook upgrades old proofs before new commits

Performance

• First backfill: 30-60s (full history scan)
• Normal commits: 10-15s (cached, minimal network)
• Attestation: ~10 min (Bitcoin block time)

Uninstall

rm .git/hooks/post-commit .git/hooks/pre-commit

Links

• OpenTimestamp
• opentimestamps-client
• Bitcoin anchoring explained

License

MIT