If a block contains no SegWit transactions, does a miner send an (empty) witness?

4

Also, would that block's Coinbase contain some kind of empty witness commitment?

pinhead

Posted 2016-11-01T20:24:45.497

Reputation: 2 356

Answers

2

BIP141 only requires a commitment to the witness tree to be present when there is at least one segwit transaction (= a transaction that spends a witness output) in the block.

This means that old miners in theory can keep working after segwit activates, as long as they don't include segwit transactions (easy, as they are nonstandard to them) and don't build on top of invalid blocks (harder, as it requires an updated full node).

Pieter Wuille

Posted 2016-11-01T20:24:45.497

Reputation: 54 032

I'm playing with this in regtest mode, but I'm seeing a SW commitment in an empty block. getblock: http://pastebin.com/eDeXGHEx and gettransaction of the coinbase tx: http://pastebin.com/3DxSFArc The block has an extra 36 bytes (size - stripped size) and the coinbase tx has an OP_RETURN aa21a9ed... Is it counting the coinbase tx itself as a SW tx? Making the whole block SW?

– pinhead – 2017-03-24T17:34:29.250

Asked: 2016-11-01T20:24:45.497

Viewed: 226 times

Active: 2016-11-03T16:23:09.407