Re: [bitcoin-dev] Segwit v2

[Johnson Lau <jl2012@xbt.hk>]

> On 27 Apr 2017, at 04:01, Luke Dashjr <luke@dashjr.org> wrote:
> 
> 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.

You can do this with witness too, which is also cheaper. Just need to make sure the signature covers a special part of the witness. I will make a proposal to Litecoin soon, which allows signing and executing extra scripts in witness. Useful for things like OP_PUSHBLOCKHASH

> 
>> 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.

Witness is cheaper and bigger

> 
> Luke