Transcript for #bitcoin-dev 2018/04/24

15:39 robzon hmm I'm playing around with theoretical data structures for blockchain... currently an OutPoint is pretty hefty (32b txid + 4b txo idx) and I was thinking whether it could be replaced with a different addressing format, like <height><tx index><output index>, which would effectively be 8b or so (assuming uint32 for height, uint16 for both tx index and txout index), but... this way would be vulnerable
15:39 robzon to chain reorgs (ie block at referenced height has changed, but the pkscript at the address would still evaluate to true, and the tx would spend the unintended output). I thought the solution might be to add chain id to the transaction header, so that the tx would be only valid if a block with a specified hash existed in the chain. that way a reorg would invalidate the tx while preserving 8-byte
15:39 robzon addressing
15:42 robzon what do you think? can you see any other problems with this solution?
15:51 robzon one more thing I see here is that txs with very recent chain id (younger than, say, 6 blocks) could not be trusted since a reorg would completely invalidate them
15:59 robzon it would also work as a future-proof replay protection