From: Pieter Wuille <pieter.wuille@gmail•com>
To: Elichai Turkel <elichai.turkel@gmail•com>,
Bitcoin Protocol Discussion
<bitcoin-dev@lists•linuxfoundation.org>
Subject: Re: [bitcoin-dev] Taproot proposal
Date: Fri, 9 Aug 2019 11:29:55 -0700 [thread overview]
Message-ID: <CAPg+sBgyhjRmVdtC1bGWkpaTtMqQRsCqKjFB=LU_fcMYUJc6jA@mail.gmail.com> (raw)
In-Reply-To: <CALN7hCJ7dCER9zaQbXvT4AVt95cZwBsQcTX8XvvZwF-1xa-V4w@mail.gmail.com>
On Fri, 9 Aug 2019 at 08:02, Elichai Turkel via bitcoin-dev
<bitcoin-dev@lists•linuxfoundation.org> wrote:
>
> Hi,
Since the idea of implicitly even pubkeys has potentially more general
implications, I've started a separate thread [1] about that idea.
> I want to add to John Newbery's suggestion of using implicit even/odd only public keys and tweaked public keys in taproot and suggest the following:
> If everything is implicit then the only reason for the first byte of the control block(`c[0]`) is the tapscript leaf version.
That's unfortunately not correct. If we want to maintain
batch-verifiability of the taproot tweaking (the Q = P + H(P,m)G
relation), we still need a bit in the control block to convey whether
a negation was necessary to make P+H(P,m)G even, even if P and Q both
have implied-even Y coordinates. Not doing that would require
exploring 2^n combinations to batch verify n relations, obviously
destroying any performance savings the batch verification had in the
first place.
> I suggest that this is moved to be the first OP_CODE of the tapscript itself (i.e. OP_0/OP_1 etc.)
> That way having the script *tells* you what does it mean without needing to check the control block.
> That way there's a separation between the tapscript+leaf version and the control block being the merkle path to the script.
If we keep the leaf version idea (it's possible to instead just rely
entirely on OP_SUCCESSx, and drop leaf versions), my preference is to
still keep it separate from script, though just for a fairly banal
reason: that way the script consists entirely of opcodes and can be
treated uniformly by debug tools, rather than needing to treat the
first byte special. I do understand your preference too, but I don't
know how it weighs up.
[1] https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2019-August/017247.html
Cheers,
--
Pieter
next prev parent reply other threads:[~2019-08-09 18:30 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-09 14:58 Elichai Turkel
2019-08-09 18:29 ` Pieter Wuille [this message]
-- strict thread matches above, loose matches on Subject: below --
2019-05-06 17:57 Pieter Wuille
2019-05-06 20:17 ` Luke Dashjr
2019-05-07 20:42 ` Sjors Provoost
2019-05-08 4:37 ` ZmnSCPxj
2019-05-08 5:16 ` ZmnSCPxj
2019-05-08 23:06 ` Pieter Wuille
2019-05-18 17:51 ` ZmnSCPxj
2019-05-08 3:44 ` ZmnSCPxj
2019-05-09 16:56 ` Johnson Lau
2019-05-10 5:38 ` ZmnSCPxj
2019-05-08 4:49 ` Anthony Towns
2019-05-08 13:10 ` Luke Dashjr
2019-05-21 17:20 ` Russell O'Connor
2019-05-23 2:06 ` Pieter Wuille
2019-05-23 2:32 ` Russell O'Connor
2019-05-22 14:14 ` John Newbery
2019-09-16 16:18 ` Greg Sanders
2019-09-17 4:09 ` ZmnSCPxj
2019-09-18 21:21 ` Pieter Wuille
2019-06-27 0:08 ` Russell O'Connor
2019-06-28 9:49 ` Anthony Towns
2019-06-28 11:16 ` Russell O'Connor
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='CAPg+sBgyhjRmVdtC1bGWkpaTtMqQRsCqKjFB=LU_fcMYUJc6jA@mail.gmail.com' \
--to=pieter.wuille@gmail$(echo .)com \
--cc=bitcoin-dev@lists$(echo .)linuxfoundation.org \
--cc=elichai.turkel@gmail$(echo .)com \
/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