From: Sergio Demian Lerner <sergio.d.lerner@gmail•com>
To: Mark Friedenbach <mark@friedenbach•org>
Cc: Bitcoin Protocol Discussion <bitcoin-dev@lists•linuxfoundation.org>
Subject: Re: [bitcoin-dev] cleanstack alt stack & softfork improvements (Was: Merkle branch verification & tail-call semantics for generalized MAST)
Date: Fri, 22 Sep 2017 18:32:00 -0300 [thread overview]
Message-ID: <CAKzdR-pnvystx5H+P+OCXm73aVmWdyesCymerSgx=pCuXx+YGA@mail.gmail.com> (raw)
In-Reply-To: <3385CE20-C1BA-40DD-8FC3-8F53F3350717@friedenbach.org>
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But generally before one signs a transaction one does not know the
signature size (which may be variable). One can only estimate the maximum
size.
On Fri, Sep 22, 2017 at 6:11 PM, Mark Friedenbach <mark@friedenbach•org>
wrote:
>
> On Sep 22, 2017, at 1:32 PM, Sergio Demian Lerner <
> sergio.d.lerner@gmail•com> wrote:
>
>
>>
>> There are other solutions to this problem that could have been taken
>> instead, such as committing to the number of items or maximum size of
>> the stack as part of the sighash data, but cleanstack was the approach
>> taken.
>
>
> The lack of signed maximum segwit stack size was one of the objections to
> segwit I presented last year. This together with the unlimited segwit stack
> size.
>
> However, committing to the maximum stack size (in bytes) for an input is
> tricky. The only place where this could be packed is in sequence_no, with a
> soft-fork. E.g. when transaction version is 2 and and only when lock_time
> is zero.
>
> For transactions with locktime >0, we could soft-fork so transactions add
> a last zero-satoshi output whose scriptPub contains OP_RETURN and followed
> by N VarInts, containing the maximum stack size of each input.
> Normally, for a 400 byte, 2-input transaction, this will add 11 bytes, or
> a 2.5% overhead.
>
>
> There’s no need to put it in the transaction itself. You put it in the
> witness and it is either committed to as part of the witness (in which case
> it has to hold for all possible spend paths), or at spend time by including
> it in the data signed by CHECKSIG.
>
>
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next prev parent reply other threads:[~2017-09-22 21:32 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-07 0:38 [bitcoin-dev] Merkle branch verification & tail-call semantics for generalized MAST Mark Friedenbach
2017-09-08 9:21 ` Johnson Lau
2017-09-12 2:03 ` Mark Friedenbach
2017-09-12 2:13 ` Bryan Bishop
2017-09-12 8:55 ` Johnson Lau
2017-09-12 19:57 ` Mark Friedenbach
2017-09-12 23:27 ` Karl Johan Alm
2017-09-13 9:41 ` Peter Todd
2017-09-11 20:37 ` Adán Sánchez de Pedro Crespo
2017-09-19 0:46 ` Mark Friedenbach
2017-09-19 3:09 ` [bitcoin-dev] cleanstack alt stack & softfork improvements (Was: Merkle branch verification & tail-call semantics for generalized MAST) Luke Dashjr
2017-09-19 7:33 ` Mark Friedenbach
2017-09-22 20:32 ` Sergio Demian Lerner
2017-09-22 21:11 ` Mark Friedenbach
2017-09-22 21:32 ` Sergio Demian Lerner [this message]
2017-09-22 21:39 ` Mark Friedenbach
2017-09-22 21:54 ` Sergio Demian Lerner
2017-09-22 22:07 ` Mark Friedenbach
2017-09-22 22:09 ` Pieter Wuille
2021-04-09 8:15 ` [bitcoin-dev] maximum block height on transaction Erik Aronesty
2021-04-09 11:39 ` Russell O'Connor
2021-04-09 15:54 ` Jeremy
2021-04-12 20:04 ` Billy Tetrud
2021-04-16 4:24 ` ZmnSCPxj
2021-05-03 2:30 ` ZmnSCPxj
2017-09-20 5:13 ` [bitcoin-dev] cleanstack alt stack & softfork improvements (Was: Merkle branch verification & tail-call semantics for generalized MAST) Johnson Lau
2017-09-20 19:29 ` Mark Friedenbach
2017-09-21 3:58 ` Johnson Lau
2017-09-21 4:11 ` Luke Dashjr
2017-09-21 8:02 ` Johnson Lau
2017-09-21 16:33 ` Luke Dashjr
2017-09-21 17:38 ` Johnson Lau
2017-09-30 23:23 ` [bitcoin-dev] Merkle branch verification & tail-call semantics for generalized MAST Luke Dashjr
2017-09-30 23:51 ` Mark Friedenbach
2017-10-02 17:15 ` Russell O'Connor
2017-10-28 4:40 ` Mark Friedenbach
2017-11-01 8:43 ` Luke Dashjr
2017-11-01 15:08 ` Mark Friedenbach
2017-11-04 7:59 ` Luke Dashjr
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