public inbox for bitcoindev@googlegroups.com
 help / color / mirror / Atom feed
From: Luke Dashjr <luke@dashjr•org>
To: bitcoin-dev@lists•linuxfoundation.org
Subject: [bitcoin-dev] Segwit v2
Date: Thu, 20 Apr 2017 20:28:52 +0000	[thread overview]
Message-ID: <201704202028.53113.luke@dashjr.org> (raw)

Since BIP 141's version bit assignment will timeout soon, and needing renewal, 
I was thinking it might make sense to make some minor tweaks to the spec for 
the next deployment. These aren't critical, so it's perfectly fine if BIP 141 
activates as-is (potentially with BIP 148), but IMO would be an improvement if 
a new deployment (non-BIP148 UASF and/or new versionbit) is needed.

1. Change the dummy marker to 0xFF instead of 0. Using 0 creates ambiguity 
with incomplete zero-input transactions, which has been a source of confusion 
for raw transaction APIs. 0xFF would normally indicate a >32-bit input count, 
which is impossible right now (it'd require a >=158 GB transaction) and 
unlikely to ever be useful.

2. Relax the consensus rules on when witness data is allowed for an input. 
Currently, it is only allowed when the scriptSig is null, and the scriptPubKey 
being spent matches a very specific pattern. It is ignored by "upgrade-safe" 
policy when the scriptPubKey doesn't match an even-more-specific pattern. 
Instead, I suggest we allow it (in the consensus layer only) in combination 
with scriptSig and with any scriptPubKey, and consider these cases to be 
"upgrade-safe" policy ignoring.

The purpose of the second change is to be more flexible to any future 
softforks. I consider it minor because we don't know of any possibilities 
where it would actually be useful.

Thoughts?

Luke


             reply	other threads:[~2017-04-20 20:29 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-04-20 20:28 Luke Dashjr [this message]
2017-04-26  8:51 ` praxeology_guy
2017-04-26 19:31 ` Johnson Lau
2017-04-26 20:01   ` Luke Dashjr
2017-04-26 20:09     ` Johnson Lau
2017-04-26 21:34     ` Russell O'Connor
2017-04-27  2:18   ` praxeology_guy

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=201704202028.53113.luke@dashjr.org \
    --to=luke@dashjr$(echo .)org \
    --cc=bitcoin-dev@lists$(echo .)linuxfoundation.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox