Subject: Re: [bitcoindev] [BIP Proposal] Mempool Validation and Relay Policies via User-Defined Scripts

From: Aiden McClelland <[email-masked]>
Date: Thu, 25 Sep 2025 15:25:46 -0600

>I have no idea what you're referring to there.

It's something I inferred from your primary argument that seems to be that
user-configurable filters are bad because they would cause censorship. But
it also sounds like you're saying such filters are completely ineffective
at any sort of censorship at all. I don't really understand how these two
viewpoints can coexist. What am I missing here?

Best,
*Aiden McClelland*

On Thu, Sep 25, 2025, 3:14 PM Greg Maxwell <[email-masked]> wrote:

> I am not a core developer. I have not been for some eight years now.
>
> > that you yourself are worried they will reach the 80% needed
>
> I have no idea what you're referring to there.  If lots of people run
> nodes that screw up propagation they'll be routed around.  I developed the
> technical concepts required to get nearly 100% tx coverage even if almost
> all nodes are blocking them quite a few years ago (
> https://arxiv.org/pdf/1905.10518 ), but deployment of the implementation
> has gone slow due to other factors (you know, such as the most
> experienced developers being hit with billions of dollars in lawsuits as a
> cost for their support of Bitcoin)... I expect if censoring actually
> becomes widespread that technological improvements which further moot it
> will be developed.
>
> These are just vulnerabilities that should be closed anyways-- after all
> anyone at any time can just spin up any number of "nodes" that behave in
> arbitrary ways, at ant time.  It's been a lower priority because there are
> other countermeasures (addnode-a-friend, manually setbanning bad peers,
> etc.) and aforementione distractions.
>
> > censorship due to widespread use of transaction filters is a bad thing
> (I'm not really taking a stance on that right now).
>
> I would point you to the history of discussion on Bitcoin starting back
> with Satoshi's earliest announcements, and perhaps to help you understand
> that if you want that what you want isn't bitcoin.  If after consideration
> you don't think censorship wouldn't be very bad, then really you and I have
> nothing further to discuss.
>
> > are you willing to work with and compromise with people who are looking
> for a solution like this? Or are you going to force them to abandon the
> Core project entirely
>
> I don't really think there is any space to compromise with people who
> think it's okay to add censorship to Bitcoin-- I mean sure whatever exact
> relay policy there is there is plenty of tradeoffs but from the start of
> this new filter debate the filter proponents have immediately come out with
> vile insults accusing developers of promoting child sexual abuse and
> shitcoins and what not----  that isn't some attempt to navigate a
> technical/political trademark, it's an effort to villify and destory the
> opposition.   And unambiguously so as luke has said outright that his goal
> is to destroy Bitcoin Core.  So what's the compromise there?
>
> > Or even worse still, felt compelled to coordinate a UASF to block these
> transactions entirely?
>
> I very much think people should do that-- they should actually make some
> consensus rules for their filters to fork off and we can see what the
> market thinks.  -- And also even if the market prefers censored Bitcoin,
> that's also fine with me, in the sense in my view Bitcoin was created to be
> money as largely free from human judgement as possible.  When it was
> created most of the world was doing something else and didn't know they
> needed freedom money.  If it's still the case that most of the world
> doesn't want freedom money that would be no shock. They should be free to
> have what they want and people who want freedom money should be free to
> have what they want.  I got into bitcoin before it was worth practically
> anything because of the freedom it provides, and I think that's paramount.
>
> Perhaps you should consider why they *don't* do that?  I'd say it's
> because (1) it won't work, and (2) it's not actually what the world wants--
> an outspoken influence campaign is not necessarily all that reflective of
> much of anything.  Particularly given how inaccurate and emotionally
> pandering the filter advocacy has been.   But, hey, I've been wrong
> before.
>
>
>
> On Thu, Sep 25, 2025 at 8:51 PM Aiden McClelland <[email-masked]> wrote:
>
>> Greg,
>>
>> Let me assume for a minute, for the sake of argument, that I agree that
>> transaction censorship due to widespread use of transaction filters is a
>> bad thing (I'm not really taking a stance on that right now). It is an
>> irrefutable fact that a very large portion of the user base wants to filter
>> transactions. So many so, that you yourself are worried they will reach the
>> 80% needed to prevent certain types of transactions from propogating.
>> Wouldn't it then be *worse* if these 80% of users went and ran an
>> alternative implementation, most likely written by it's most radical
>> supporters? Or even worse still, felt compelled to coordinate a UASF to
>> block these transactions entirely?
>>
>> I at no point intended to insinuate that you or any other core
>> contributer be compelled to implement a proposal like this. It's up to its
>> supporters to do so. The real question is, are you willing to work with and
>> compromise with people who are looking for a solution like this? Or are you
>> going to force them to abandon the Core project entirely?
>>
>> Best,
>> *Aiden McClelland*
>>
>> On Thu, Sep 25, 2025, 2:03 PM Greg Maxwell <[email-masked]> wrote:
>>
>>> > 1) Allowing node
>>>
>>> Who said anything about allowing?  Everyone is allowed to do whatever
>>> they want.  Drill a hole in your head if you like, not my concern.  None of
>>> this thread is about what people are allowed to do-- that's off the table.
>>> The design and licensing of Bitcoin is such that no one gets to stop anyone
>>> else from what they want to do anyways (which is, in fact, a big part of
>>> the issue here).   To think otherwise is to be stuck in a kind of serf
>>> thinking where you can only do what other people allow you to do.  That has
>>> never been what Bitcoin was about.
>>>
>>> Rather, the question is should people who care about Bitcoin spend their
>>> time and money developing infrastructure that would be useful, even
>>> primarily useful, for censorship.  I say no.  Especially because any time
>>> spent on it is time away from anti-censorship pro-privacy tools and because
>>> the effort spent doing so would undermine anti-censorship and pro-privacy
>>> efforts because they would inevitably moot the efforts expected getting
>>> into peoples business and filtering their transactions.
>>>
>>> You don't have to agree, and you're free to do your own thing just as
>>> I'm free to say that I think it's a bad direction.  From the very beginning
>>> Bitcoin has stood against the freedom to transact being overridden by
>>> some admin based on their judgment call weighing principles against other
>>> concerns, or at the behest of their superiors.  So many Bitcoiner will
>>> stand against, route around, and do what they can do to make ineffectual
>>> the blocking of consensual transactions.  It might not seem as many at the
>>> moment, but the pro-privacy and anti-censorship 'side' doesn't have a paid
>>> PR and influence campaign,  but it also doesn't matter so much because
>>> Bitcoin takes advantage of the nature of information being easy to spread
>>> and hard to stifel and it doesn't that that huge an effort to route around
>>> censorship efforts.
>>>
>>> There are elements of anti-censorship in Bitcoin that have been so far
>>> underdeveloped.  It's unfortunate that their further development might be
>>> forced at a time when efforts are needed on other areas.  But perhaps they
>>> wouldn't get done without a concrete motivation. Such is life.
>>>
>>>
>>>
>>>
>>>
>>> On Thu, Sep 25, 2025 at 9:21 AM yes_please <[email-masked]>
>>> wrote:
>>>
>>>> Sorry Greg, could you please elaborate further on your ideas? Some are
>>>> not exactly clear:
>>>>
>>>> 1) Allowing node runners to configure their node as they please and
>>>> refuse to relay some txs is considered authoritarian, censorship, and an
>>>> attempt to regulate third parties conduct. On the other hand, forcing nodes
>>>> to merge towards a single shared configuration (by preventing them to block
>>>> txs) is not considered authoritarian because this imposition does not
>>>> discriminate towards any txs and is thus non-authoritarian? Did I get the
>>>> reasoning correctly here?
>>>>
>>>> 2) If the aim is to have a homogenous mempool state and to model what
>>>> will get mined, shouldn’t we reach this state through distributed
>>>> independent nodes who decide independently on what they prefer this
>>>> homogenous state to be? If we don’t reach this state through this
>>>> distributed/independent mechanism, then how are we to reach this state? Who
>>>> gets to decide and steer the direction so that we all converge towards this
>>>> homogenous state?  One of the strongest aspects of bitcoin is the fact that
>>>> no single party can force a change/direction, and the network has to
>>>> somehow reach a shared agreement through independent decision makers who
>>>> act in what manner they think is best. The proposed BIP seems to be aligned
>>>> with such a principle, I fail to see any authoritarian aspect here.
>>>>
>>>> 3) I share your sentiment and the aim to have a homogenous mempool
>>>> state, but I am skeptical of the manner in which we are to achieve this
>>>> according to the ideas you have here expressed (namely not through a
>>>> distributed independent organic manner)
>>>>
>>>>
>>>> Respectfully, yes_please
>>>>
>>>> On Thu, Sep 25, 2025 at 12:50 AM Greg Maxwell <[email-masked]>
>>>> wrote:
>>>>
>>>>> So that when the "consistent state" changes as a result of some issue
>>>>> you can update configs instead of having to update software-- which has
>>>>> considerable more costs and risks, especially if you're carrying local
>>>>> customizations as many miners do.
>>>>>
>>>>>
>>>>> On Wed, Sep 24, 2025 at 8:47 PM Aiden McClelland <[email-masked]>
>>>>> wrote:
>>>>>
>>>>>> If mempool consistency across the network is all that is important,
>>>>>> why allow any configuration of mempool relay policies at all?
>>>>>>
>>>>>> On Wednesday, September 24, 2025 at 12:47:28 PM UTC-6 Greg Maxwell
>>>>>> wrote:
>>>>>>
>>>>>>> This appears to substantially misunderstands the purpose of the
>>>>>>> mempool broadly in the network-- it's purpose is to model what will get
>>>>>>> mined.  If you're not doing that you might as well set blocks only.
>>>>>>> Significant discrepancies are harmful to the system and promote
>>>>>>> centralization and fail to achieve a useful purpose in any case.  What
>>>>>>> marginal benefits might be provided do not justify building and deploying
>>>>>>> the technological infrastructure for massive censorship.
>>>>>>>
>>>>>>> If you think this is important, I advise you to select another
>>>>>>> cryptocurrency which is compatible with such authoritarian leanings.  --
>>>>>>> though I am unsure if any exist since it is such a transparently pointless
>>>>>>> direction.
>>>>>>>
>>>>>>>
>>>>>>> On Wed, Sep 24, 2025 at 6:30 PM Aiden McClelland <[email-masked]>
>>>>>>> wrote:
>>>>>>>
>>>>>>>> Hi all,
>>>>>>>>
>>>>>>>> I'd like to share for discussion a draft BIP to allow for a modular
>>>>>>>> mempool/relay policy: https://github.com/bitcoin/bips/pull/1985
>>>>>>>>
>>>>>>>> I think it could potentially reduce conflict within the community
>>>>>>>> around relay policy, as an alternative to running lots of different node
>>>>>>>> implementations/forks when there are disagreements.
>>>>>>>>
>>>>>>>> I am working on a reference implementation using Bellard's QuickJS,
>>>>>>>> but it has been almost a decade since I've written C++, so it's slow going
>>>>>>>> and I'm sure doesn't follow best-practices. Once it's working, it can be
>>>>>>>> cleaned up.
>>>>>>>>
>>>>>>>> Thanks,
>>>>>>>> Aiden McClelland
>>>>>>>>
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>>>>>>
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>>>>> .
>>>>>
>>>>

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