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Wed, 15 Apr 2026 09:50:00 -0700 (PDT) X-Received: by 2002:a05:6808:c1a6:b0:467:de0e:fe9a with SMTP id 5614622812f47-4789fb10794mr11219310b6e.25.1776271800605; Wed, 15 Apr 2026 09:50:00 -0700 (PDT) Received: by 2002:a05:690c:a60d:b0:7b3:13f7:5f3a with SMTP id 00721157ae682-7b712a1a29ems7b3; Wed, 15 Apr 2026 09:30:50 -0700 (PDT) X-Received: by 2002:a05:690c:39a:b0:79a:8f2f:cb3 with SMTP id 00721157ae682-7af71b50963mr225440027b3.44.1776270649892; Wed, 15 Apr 2026 09:30:49 -0700 (PDT) Date: Wed, 15 Apr 2026 09:30:49 -0700 (PDT) From: b10c <0xb10c@gmail.com> To: Bitcoin Development Mailing List Message-Id: <8bc588f8-38fd-4ebc-a02d-ae750764bd0cn@googlegroups.com> In-Reply-To: References: <273ith9pPyipCI5hjV6ETFBzFhM4xFN8ptEFK8zc5N-jxGwOBvEn5r9Bt2c9p0A-6-3Bs53gONglzo1QfI4LCIOwkJgR9PWT4iQT_Wbpllo=@protonmail.com> Subject: Re: [bitcoindev] BIP 54 active on Bitcoin Inquisition MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="----=_Part_177746_2146239859.1776270649437" X-Original-Sender: 0xB10C@gmail.com Precedence: list Mailing-list: list bitcoindev@googlegroups.com; contact bitcoindev+owners@googlegroups.com List-ID: X-Google-Group-Id: 786775582512 List-Post: , List-Help: , List-Archive: , List-Unsubscribe: , X-Spam-Score: -0.5 (/) ------=_Part_177746_2146239859.1776270649437 Content-Type: multipart/alternative; boundary="----=_Part_177747_751826203.1776270649437" ------=_Part_177747_751826203.1776270649437 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Hi, My approach so far has been to share all details in the semi-private=20 Delving thread that is accessible to a number of experts who would be able= =20 to figure it out on their own anyway, and to share a demonstration of an=20 expensive-but-far-from-worst block publicly. Anthony Towns and i performed such a demo last week on Signet. There was yet another demo of this on April 8th and 9th. It's documented=20 on https://delvingbitcoin.org/t/consensus-cleanup-demo-of-slow-blocks-on-si= gnet/2367=20 and had quite a few participants running it and sharing their block=20 validation times across a wide range of CPUs. For the recent demo, I set up some P2P monitoring with a custom client that= =20 connects to all ~190 listening Signet on IPv4 and Tor. This client, for=20 example, requested high-bandwith compact blocks from all nodes and kept=20 track of Bitcoin protocol ping-pong RTT times. Recoding timestamps of block= =20 annoucements and the time when a peer would respond to my getblocktxn=20 requests with blocktxn's allows to monitor validation times across the=20 network (limited to the listening part of the network). I've written about it in detail=20 on https://bnoc.xyz/t/block-propagation-and-validation-duration-during-slow= -to-validate-blocks-on-signet/117 I'm writing here to share a few numbers: - during normal network conditions, a median listening node on Signet takes= =20 176ms to validate a block (25th percentile: 37ms; 75th percentile 447ms).= =20 Almost all listening nodes can validated the normal blocks in less than a= =20 second. - during the slow-to-validate event last week, it took a median listing=20 node 19.7s to validate a block (25th percentile 8.2s; 75th percentile 32s).= =20 The 90th percentile takes close to 80s. - When looking at the mulitple, the median validation takes about 160x=20 longer than validationg a normal block (25th percentile: 31x, 75th=20 percentile: 793x).=20 Keep in mind that these numbers are for the "expensive-but-far-from-worst= =20 blocks" that Antoine chose to disclose. Best b10c On Wednesday, March 11th, 2026 at 11:27 AM, 'Antoine Poinsot' via Bitcoin= =20 Development Mailing List wrote: I share this concern, which is why i only shared details about this in the= =20 (semi-)private Delving thread to this effect:=20 https://delvingbitcoin.org/t/worst-block-validation-time-inquiry/711. The testing for quality assurance has already been performed as part of the= =20 investigation into the various techniques and possible mitigations.=20 Additional testing is always valuable, but the primary goal of a public=20 demonstration for this would be to help build consensus. It's a fine line to tread, because on the one hand you do not want to give= =20 away the details of how to optimise the attack (whether for maximum profit= =20 or for maximum impact), but on the other hand i do think it's necessary to= =20 provide some amount of publicly verifiable information to support a soft=20 fork activation proposal. My approach so far has been to share all details in the semi-private=20 Delving thread that is accessible to a number of experts who would be able= =20 to figure it out on their own anyway, and to share a demonstration of an=20 expensive-but-far-from-worst block publicly. This allows anyone to check=20 for themselves that it is indeed possible to craft *some*=E2=80=8B slow blo= cks, and=20 they can refer to an expert to confirm that it can be made much worse. Of= =20 course, i remain open to feedback. On Wednesday, February 25th, 2026 at 12:03 PM, Jameson Lopp < jameso...@gmail.com> wrote: The main concern I'd have is whether or not doing so would leak more=20 information to the world about how to conduct such an attack on mainnet. It= =20 may be prudent to perform such testing privately. On Fri, Feb 13, 2026 at 5:28=E2=80=AFPM 'Antoine Poinsot' via Bitcoin Devel= opment=20 Mailing List wrote: Hi everyone, Bitcoin Inquisition 29.2 was released last week with support for BIP 54=20 (Consensus Cleanup) [0]. BIP 54 is now active on Inquisition since block 291168. By virtue of being a bugfix soft fork rather than introducing new features,= =20 there is fewer avenues for testing on the public Signet network. Perhaps we could create a Signet= =20 block that is slow but not quite as bad as the worst case, and share it here to demonstrate it is= =20 now invalid on Inquisition? At any rate, please let us know if you find anything in testing whether it= =20 is on the public Signet network, in private ones, or however else. Best, Antoine Poinsot [0] https://delvingbitcoin.org/t/bitcoin-inqusition-29-2/2236 --=20 You received this message because you are subscribed to the Google Groups= =20 "Bitcoin Development Mailing List" group. To unsubscribe from this group and stop receiving emails from it, send an= =20 email to bitcoindev+...@googlegroups.com. To view this discussion visit=20 https://groups.google.com/d/msgid/bitcoindev/wJZkcSEOQD5Z8rsel8TJCSkUJiwn7Y= epjyOfSDHKt3P_4Fvh9MFu_oiva3G6C-Q_1CmRTCj6lqmVm6ZeZG8WbdVrCo4IZUFg3VazRdJ48= AQ%3D%40protonmail.com . --=20 You received this message because you are subscribed to the Google Groups= =20 "Bitcoin Development Mailing List" group. To unsubscribe from this group and stop receiving emails from it, send an= =20 email to bitcoindev+...@googlegroups.com. To view this discussion visit=20 https://groups.google.com/d/msgid/bitcoindev/CADL_X_ewFMqLuv7MVfWCZf3QhKezW= 9xiS19xWdROjtoT9dmU7w%40mail.gmail.com . --=20 You received this message because you are subscribed to the Google Groups= =20 "Bitcoin Development Mailing List" group. To unsubscribe from this group and stop receiving emails from it, send an= =20 email to bitcoindev+...@googlegroups.com. To view this discussion visit=20 https://groups.google.com/d/msgid/bitcoindev/273ith9pPyipCI5hjV6ETFBzFhM4xF= N8ptEFK8zc5N-jxGwOBvEn5r9Bt2c9p0A-6-3Bs53gONglzo1QfI4LCIOwkJgR9PWT4iQT_Wbpl= lo%3D%40protonmail.com . --=20 You received this message because you are subscribed to the Google Groups "= Bitcoin Development Mailing List" group. To unsubscribe from this group and stop receiving emails from it, send an e= mail to bitcoindev+unsubscribe@googlegroups.com. To view this discussion visit https://groups.google.com/d/msgid/bitcoindev/= 8bc588f8-38fd-4ebc-a02d-ae750764bd0cn%40googlegroups.com. ------=_Part_177747_751826203.1776270649437 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
Hi,
My approach so far = has been to share all details in the semi-private Delving thread that is ac= cessible to a number of experts who would be able to figure it out on their= own anyway, and to share a demonstration of an expensive-but-far-from-wors= t block publicly.

Anthon= y Towns and i performed such a demo last week on Signet.
=

There was yet another demo of this on April 8th and 9= th. It's documented on=C2=A0https://delvingbitcoin.org/t/consensus-cleanup-= demo-of-slow-blocks-on-signet/2367 and had quite a few participants running= it and sharing their block validation times across a wide range of CPUs.

For the recent demo, I set up some P2P monitoring= with a custom client that connects to all=C2=A0~190 listening Signet on IP= v4 and Tor. This client, for example, requested high-bandwith compact block= s from all nodes and kept track of Bitcoin protocol ping-pong RTT times. Re= coding timestamps of block annoucements and the time when a peer would resp= ond to my getblocktxn requests with blocktxn's allows to monitor validation= times across the network (limited to the listening part of the network).

I've written about it in detail on=C2=A0https://b= noc.xyz/t/block-propagation-and-validation-duration-during-slow-to-validate= -blocks-on-signet/117

I'm writing here to share = a few numbers:
- during normal network conditions, a median liste= ning node on Signet takes 176ms to validate a block (25th percentile: 37ms;= 75th percentile 447ms). Almost all listening nodes can validated the norma= l blocks in less than a second.
- during the slow-to-validate eve= nt last week, it took a median listing node 19.7s to validate a block (25th= percentile 8.2s; 75th percentile 32s). The 90th percentile takes close to = 80s.
- When looking at the mulitple, the median validation takes = about 160x longer than validationg a normal block (25th percentile: 31x, 75= th percentile: 793x).=C2=A0

Keep in mind that th= ese numbers are for the "expensive-but-far-from-worst blocks" that Antoine = chose to disclose.

Best
b10c


On Wednesday, March 11th, 2026 at 11:27 AM, 'Antoine Poinsot' via B= itcoin Development Mailing List <bitco...@= googlegroups.com> wrote:
I share this concern, which is why i only shared details about this in the= (semi-)private Delving thread to this effect:=C2=A0https://delvingbitcoin.org/t/wo= rst-block-validation-time-inquiry/711.

The testing for quality assura= nce has already been performed as part of the investigation into the variou= s techniques and possible mitigations. Additional testing is always valuabl= e, but the primary goal of a public demonstration for this would be to help= build consensus.

It's a fine line to tread, because on the one hand you do not = want to give away the details of how to optimise the attack (whether for ma= ximum profit or for maximum impact), but on the other hand i do think it's = necessary to provide some amount of publicly verifiable information to supp= ort a soft fork activation proposal.

My approach so far has been to share all de= tails in the semi-private Delving thread that is accessible to a number of = experts who would be able to figure it out on their own anyway, and to shar= e a demonstration of an expensive-but-far-from-worst block publicly. This a= llows anyone to check for themselves that it is indeed possible to craft some=E2=80=8B slow blocks, and they can refer to an expert to confirm = that it can be made much worse. Of course, i remain open to feedback.
=
On Wednesday, February 25th, 2026 at 12:03 PM, Jameson Lopp <jameso...@gmail.com> wrote:
The main concern I'd have is whether or not do= ing so would leak more information to the world about how to conduct such a= n attack on mainnet. It may be prudent to perform such testing privately.
On Fri, Feb 13, 2026 at 5:28=E2=80=AFPM 'An= toine Poinsot' via Bitcoin Development Mailing List <bitco...@googlegroups.com> wrote:
Hi everyone,

Bitcoin Inquisition 29.2 was released last week with support for BIP 54 (Co= nsensus Cleanup) [0]. BIP
54 is now active on Inquisition since block 291168.

By virtue of being a bugfix soft fork rather than introducing new features,= there is fewer avenues
for testing on the public Signet network. Perhaps we could create a Signet = block that is slow but
not quite as bad as the worst case, and share it here to demonstrate it is = now invalid on
Inquisition?

At any rate, please let us know if you find anything in testing whether it = is on the public Signet
network, in private ones, or however else.

Best,
Antoine Poinsot

[0] https://delvingbitcoi= n.org/t/bitcoin-inqusition-29-2/2236

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