From: Anthony Towns <aj@erisian•com.au>
To: Rusty Russell <rusty@rustcorp•com.au>,
Bitcoin Protocol Discussion
<bitcoin-dev@lists•linuxfoundation.org>
Subject: Re: [bitcoin-dev] Proposed BIP for OP_CAT
Date: Mon, 23 Oct 2023 22:26:26 +1000 [thread overview]
Message-ID: <ZTZmcis5IkIGazYq@erisian.com.au> (raw)
In-Reply-To: <871qdmulvt.fsf@rustcorp.com.au>
On Mon, Oct 23, 2023 at 12:43:10PM +1030, Rusty Russell via bitcoin-dev wrote:
> 2. Was there a concrete rationale for maintaining 520 bytes?
Without a limit of 520 bytes, then you can construct a script:
<p> CHECKSIGVERIFY
{DUP CAT}x10
(we know have a string that is the second witness repeated 1024 times
on the stack; if it was 9 bytes, call it 9216B total)
{DUP} x 990
(we now have 1000 strings each of length 9216B bytes, for ~9.2MB total)
SHA256SUM {CAT SHA256SUM}x999
(we now have a single 32B field on the stack)
<h> EQUAL
(and can do a hardcoded check to make sure there weren't any
shortcuts taken)
That raises the max memory to verify a single script from ~520kB (1000
stack elements by 520 bytes each) to ~10MB (1000 stack elements by
10kB each).
> 10k is the current script limit, can we get closer to that? :)
The 10k limit applies to scriptPubKey, scriptSig and segwit v0 scripts.
There's plenty of examples of larger tapscripts, eg:
https://mempool.space/tx/0301e0480b374b32851a9462db29dc19fe830a7f7d7a88b81612b9d42099c0ae
(3,938,182 bytes of script, non-standard due to being an oversized tx)
https://mempool.space/tx/2d4ad78073f1187c689c693bde62094abe6992193795f838e8be0db898800434
(360,543 bytes of script, standard, I believe)
Cheers,
aj
next prev parent reply other threads:[~2023-10-23 12:26 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-21 5:08 Ethan Heilman
2023-10-21 5:49 ` alicexbt
2023-10-21 15:03 ` Andrew Poelstra
2023-10-26 16:04 ` James O'Beirne
2023-10-21 16:10 ` Greg Sanders
2023-10-21 20:24 ` Ethan Heilman
2023-10-22 8:58 ` vjudeu
2023-10-24 19:47 ` Steven Roose
2023-10-26 1:53 ` Ethan Heilman
2023-10-23 2:13 ` Rusty Russell
2023-10-23 12:26 ` Anthony Towns [this message]
2023-10-23 13:41 ` Andrew Poelstra
2023-10-24 0:48 ` Rusty Russell
2023-10-24 1:17 ` Andrew Poelstra
2023-10-24 3:45 ` Rusty Russell
2023-10-24 13:05 ` Andrew Poelstra
2023-10-26 21:55 ` Peter Todd
2023-10-27 18:32 ` Anthony Towns
2023-10-23 5:13 vjudeu
2023-10-26 14:30 ` Ryan Grant
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