Chatting with Deepseek about this.

### **Core Idea: Time-Locked Ownership Proofs**

1. **Concept**

- OpenTimestamps or similar proofs could cryptographically attest that you controlled a public key (and thus its UTXOs) **before a defined "quantum vulnerability cutoff date."**

- A future soft fork could *require* such proof + a new quantum-safe signature to spend:

*"Prove you owned this UTXO pre-quantum-threat to unlock it."*

2. **Technical Feasibility**

- **Possible at protocol level**: Bitcoin Script could enforce:

`[post-quantum sig] + [pre-quantum ownership proof]`

- **OpenTimestamps** (or a more robust alternative) could provide the proof.

### **Major Challenges**

1. **Consensus Coordination**

- Requires unanimous agreement to "freeze" vulnerable UTXOs until the new rules activate.

- *Reality*: Many users won’t timestamp proofs. What happens to their coins? Hard forks risk chain splits.

2. **Defining "Vulnerable" UTXOs**

- Only UTXOs with *exposed public keys* (reused addresses, post-spend states) are quantum-vulnerable.

- New addresses (public keys never spent from) remain safe. The system must distinguish these.

3. **Edge Cases**

- **Lost proofs**: Users with legitimate coins but no timestamped proof couldn’t spend.

- **Inheritance**: Transferring "frozen" coins pre-activation becomes impossible.

- **Miners/Gaslighting**: Miners might reject proofs to steal coins via quantum theft.

4. **Incentive Misalignment**

- Miners earn fees from *transactions*, not frozen coins. They may oppose rules that reduce liquidity.

### **Practical Alternatives Being Explored**

- **Automated Key Rotation**: Wallets auto-move funds to quantum-safe addresses pre-spend (e.g., via Taproot upgrades).

- **Output-Linking**: New UTXOs require explicit "input proofs" from old transactions (simpler than global timestamping).

- **Emergency Hard Fork**: Disable ECDSA entirely after a block height, forcing migration to post-quantum sigs (e.g., Lamport, SPHINCS+).

### **Your Action Plan Today**

1. **Timestamp proofs** for critical UTXOs via [OpenTimestamps](https://opentimestamps.org/) (low cost, high upside).

2. **Never reuse addresses** (public keys stay hidden until spend).

3. **Monitor** Bitcoin Improvement Proposals (BIPs) for quantum transitions like [BIP 340-342](https://github.com/bitcoin/bips) (Schnorr/Taproot foundations).

### **Bottom Line**

Your idea **could work** for *your coins* if:

- You timestamp proofs now,

- The network adopts your proposed rules, *and*

- No critical edge cases break it.

However, as a *universal solution*, it's less viable than protocol-level key rotation or output-linking. Time-limited soft forks (e.g., 90-day migration windows) are more likely if quantum threats materialize.

> ℹ️ **Status**: Theoretical – no formal BIP exists for this. Research is active in [post-quantum Bitcoin working groups](https://blockstream.com/).