From: Christian Decker <decker.christian@gmail•com>
To: Luke Dashjr <luke@dashjr•org>, bitcoin-dev@lists•linuxfoundation.org
Subject: Re: [bitcoin-dev] [BIP] Normalized transaction IDs
Date: Wed, 21 Oct 2015 07:39:45 +0000 [thread overview]
Message-ID: <CALxbBHVdXrdh6fdSyLdkPP_D4MSbofOr01kc9L9QuQTWZ33N1w@mail.gmail.com> (raw)
In-Reply-To: <201510210618.56159.luke@dashjr.org>
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On Wed, Oct 21, 2015 at 8:19 AM Luke Dashjr <luke@dashjr•org> wrote:
> On Monday, October 19, 2015 2:01:04 PM Christian Decker via bitcoin-dev
> wrote:
> > The proposal is implemented (see below), by computing the normalized
> > transaction ID when adding them to the UTXO and storing them along with
> the
> > coin state. OP_CHECKSIGEX mostly duplicates OP_CHECKSIG and
> > OP_CHECKMULTISIG, but I'm hoping somebody can give me some pointers into
> > how to best refactor the common functionality into reusable blocks. And
> the
> > annotating incoming transactions with their normalized inputs is a bit
> > cumbersome, maye somebody has some pointers here as well?
> This doesn't completely close malleability (which should be documented in
> the
> BIP), so I'm not sure it's worth the cost, especially if closing
> malleability
> later on would need more. How about specifying flags upfront in the UTXO-
> creating transaction specifying which parts the signature will cover? This
> would allow implementation of fully malleability-proof wallets.
>
As far as I see it the only remaining venues for malleability are the use
of sighash flags that are not SIGHASH_ALL, as mentioned in the BIP. Any use
of non-sighash_all flags is already an explicit permission to modify the
transactions, by adding and removing inputs and outputs, so I don't see how
these can be made non-malleable. Am I missing something?
>
> Additionally, you have a flag to control whether the opcode behaves as
> VERIFY
> or not. Non-VERIFY is not possible as a softfork (without doing a
> second/new
> P2SH) since it can be negated.
>
Yes, this is my mistake and has been pointed out in the PR, I will amend
the PR to make the verify flag mandatory, which also guarantees that the
top of the stack contains a non-null element, thus resulting in a
successful evaluation on non-updated clients.
>
> Luke
>
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next prev parent reply other threads:[~2015-10-21 7:39 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-19 14:01 Christian Decker
2015-10-19 15:23 ` Tier Nolan
2015-10-19 19:28 ` Christian Decker
2015-10-19 22:22 ` s7r
2015-10-20 10:30 ` Christian Decker
2015-10-21 6:18 ` Luke Dashjr
2015-10-21 7:39 ` Christian Decker [this message]
2015-10-21 7:52 ` Luke Dashjr
2015-10-21 8:31 ` Christian Decker
2015-10-21 8:39 ` Luke Dashjr
2015-10-21 8:44 ` Christian Decker
2015-10-21 8:46 ` Luke Dashjr
2015-10-21 18:22 ` Danny Thorpe
2015-10-21 19:27 ` Gregory Maxwell
2015-10-21 23:20 ` Luke Dashjr
2015-10-22 8:26 ` Christian Decker
2015-10-22 8:57 ` Gregory Maxwell
2015-10-22 11:54 ` Christian Decker
2015-10-22 9:05 ` Luke Dashjr
2015-11-03 20:37 ` Christian Decker
2015-11-03 20:48 ` Luke Dashjr
2015-11-03 21:44 ` Christian Decker
2015-11-03 22:01 ` Luke Dashjr
2015-11-05 15:27 ` Jorge Timón
2015-11-05 19:36 ` Luke Dashjr
2015-11-05 20:25 ` Jorge Timón
2015-11-05 22:46 ` s7r
2015-11-05 22:29 ` Adam Back
2015-11-06 14:52 ` Christian Decker
2015-11-04 4:00 ` Peter Todd
2015-11-05 9:38 ` Christian Decker
2015-10-21 7:48 ` Gregory Maxwell
2015-10-21 8:26 ` Gregory Maxwell
2015-10-21 8:49 ` Christian Decker
2015-10-21 8:50 ` Christian Decker
2015-10-21 10:14 ` Gregory Maxwell
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