Re: [bitcoin-dev] Segwit v2

[Luke Dashjr <luke@dashjr.org>]

On Wednesday 26 April 2017 7:31:38 PM Johnson Lau wrote:
> I prefer not to do anything that requires pools software upgrade or wallet
> upgrade. So I prefer to keep the dummy marker, and not change the
> commitment structure as suggested by another post.

Fair enough, I guess. Although I think the dummy marker could actually be non-
consensus critical so long as the hashing replaces it with a 0.

> For your second suggestion, I think we should keep scriptSig empty as that
> should be obsoleted. If you want to put something in scriptSig, you should
> put it in witness instead.

There are things scriptSig can do that witness cannot today - specifically add 
additional conditions under the signature. We can always obsolete scriptSig 
later, after segwit has provided an alternative way to do this.

> Maybe we could restrict witness to IsPushOnly() scriptPubKey, so miners
> can’t put garbage to legacy txs.

They already can malleate transactions and add garbage to the blocks. I don't 
see the benefit here.

Luke