I was just reading about the two following scenarios:
My understanding is that we have two transactions here that don't follow the usual scriptSig/scriptPubKey situation, and I think transactions like these are sometimes called "contracts". In both cases, some funds were sent to a bitcoin address, so they are valid UTXO's floating around in the UTXO set, but instead of the usual situation where someone just needs to provide 0-knowledge-proof that they have private keys associated with that address, something else needs to be done to "unlock the funds". (find the data, or find a collision).
I have some questions:
- How would people (likely power users) even be aware that these funds were out there, and available to be redeemed if they solved the puzzles. Did the creators of the transactions likely announce somewhere (via forums or internet), or could someone with full node / full blockchain build a tool that watches for these types of special PKscripts?
- What does it mean in the second photo when it says "Note that while transactions like this are fun, they are not secure, because they do not contain any signatures and thus any transaction attempting to spend them can be replaced with a different transaction sending the funds somewhere else.". It seems to me if someone solved the puzzle they could immediately send the funds to themselves with the standard PKscript. What does it mean the transaction could be "replaced"?
- What kind of wallet or software would a power user claiming these funds be using? Certainly one couldn't just hop on a ledger s and try to claim these funds with the solution to the puzzle. It seems you would need more freedom to provide the puzzle solution.