Introduction: A New Controversy in Bitcoin’s Evolution
If you hold Bitcoin, if you call yourself a Bitcoiner, are you prepared to accept that the Bitcoin blockchain could be used to store illicit, even illegal content? This isn’t a hypothetical. Unless we act, by October 2025 the default Bitcoin Core software will make this the new reality. And if you don’t react now, your silence means acceptance.
Bitcoin is facing a pivotal controversy that cuts to the heart of its identity. The debate centres on a proposed change in Bitcoin’s core software that would remove longstanding limits on storing arbitrary data in transactions. On the surface, this change sounds technical – raising the OP_RETURN data limit from 80 bytes to nearly 4 megabytes, but its implications are profoundly human. Supporters hail it as an overdue embrace of censorship-resistance, while critics warn it could turn the blockchain into a host for illegal or abusive content. As a Bitcoiner who champions self-sovereignty and Bitcoin’s reputation as sound money, I find myself firmly in the latter camp. This article, written from my personal perspective and drawing on my book’s focus (Brick by Brick - <https://twentyone.life/brick-by-brick>) on self-sovereignty, explores why I’m taking a stand by running alternative software and even boycotting certain services, all in the name of a “clean” future for Bitcoin.
Background: Bitcoin Core v30 and the OP_RETURN Debate
At issue is a change slated for the upcoming Bitcoin Core version 30 (expected October 2025). Bitcoin Core is the dominant software for running nodes (over 75% of nodes run so its defaults largely define network behaviour. The core developers have decided to unshackle the OP_RETURN field, which historically allowed embedding only a tiny piece of data (≤83 bytes) in a transaction. This limit acted as a de facto “spam filter”, discouraging users from turning Bitcoin’s ledger into a generic data storage system.
Under Core v30, that filter is being removed entirely: users will be able to attach much larger data payloads, up to the size of a full block (~4MB), in a single transaction output. Moreover, Bitcoin Core will eliminate the configuration options (data carrier settings) that previously let node operators refuse relaying big OP_RETURN transactions. In short, the new default policy is “anything goes” for data, and individual node runners won’t easily opt out. While v30 still offers command-line tweaks to impose custom limits, those are now deprecated warnings likely to be removed later.
Why make this change? Proponents argue it’s a pragmatic response to reality. The 80-byte cap, they say, has been routinely bypassed by creative users who already insert larger data through other means – for example, using Taproot witness data or fake outputs (as seen in the 2023 Ordinals/“inscriptions” craze that let people embed images and art on Bitcoin). These workarounds are actually worse for the network: since the data is hidden in spendable outputs or witness scripts, it can bloat the UTXO set (the list of unspent coins) and increase validation costs for all nodes. By contrast, OP_RETURN outputs are provably unspendable and easily prunable. In the eyes of Core developers, it’s better to let people put data in OP_RETURN (where it doesn’t harm UTXO or decentralisation) than to have them continue abusing more harmful trick. Removing the cap “yields at least two tangible benefits: a cleaner UTXO set and more consistent default behaviour,” explained developer Greg Sanders. The change also aligns with Bitcoin’s values of neutrality, if a transaction is valid and pays the fee, who are nodes to censor it? Core maintainers like Gloria Zhao argue that trying to filter transactions at the node level is futile and against the principle of censorship-resistance.
On the other side, critics are alarmed. They counter that dropping these limits will open the floodgates to arbitrary data, fundamentally altering Bitcoin’s purpose. The blockchain could become a bloated “immutable database” of random content, potentially crowding out financial transactions with higher fees and diluting Bitcoin’s use as peer-to-peer money. What’s more, unbounded data storage invites spam, people could stuff blocks with endless memes, ads, or junk simply because they’re willing to pay. It’s a replay of the Blocksize War arguments, but instead of bigger blocks for payments, it’s bigger payloads for non-monetary data. The community is starkly divided: should Bitcoin evolve to support broader use cases (data, NFTs, digital artifacts), or should it resist becoming a free-for-all content repository and stick to financial utility? These positions are diametrically opposed, and the conflict has been heated – drawing comparisons to the acrimony of the 2017 blocksize debates.
Notably, longtime Bitcoin developer Luke Dashjr (author of an alternative client called Bitcoin Knots - https://x.com/LukeDashjr) has been one of the most vocal opponents besides Bitcoin Mechanic and Bitcoin University ( primal.net/kratter). He warns that the removal of what he bluntly calls “spam filters” is potentially harmful to the network and its users. Dashjr has publicly urged node operators to avoid upgrading to Core v30 or to switch to alternative software like Bitcoin Knots. In fact, many Bitcoiners have already acted on that advice. When the OP_RETURN plan was announced and fast-tracked earlier this year, there was a surge of users migrating their nodes from Core to Knots, by some estimates, over 15% of previously Core nodes switched to Bitcoin Knots in protest. The stage is set for a grass-roots pushback using Bitcoin’s own strength: decentralisation. True to the mantra of self-sovereignty, if you disagree with the default rules, you are free to run a node that reflects your values. I count myself among those taking that step.
Illicit Content on the Blockchain: The Serious Risks
Why am I, and others, so concerned about lifting the data limits? Because it’s not just “cute cat pictures” or art collections that could find their way onto Bitcoin’s ledger. The most dire possibility is the inclusion of illicit and abusive content in an immutable, globally replicated chain. This isn’t idle paranoia; it’s a genuine risk recognised by both sides of the debate. Even the advocates of OP_RETURN freedom acknowledge the “undesirable second-order effects” that could follow. Let’s spell it out: What if someone starts embedding child sexual abuse material (CSAM) or other illegal data in Bitcoin transactions? Once mined into a block, that content is there forever, every full node would unknowingly host it on their hard drive as part of the blockchain spreaded on tens of thousands nodes across the world. This scenario is a nightmare for obvious moral reasons, and it also poses a legal and reputational threat to anyone running a node or the Bitcoin network as a whole. Besides this, to spin up a new node will take longer and need higher technical hardware which leads to centralisation.
Unfortunately, the threat is not theoretical. It has already happened on a small scale. Researchers have found that forbidden content made its way onto Bitcoin as early as 2013, albeit in an obscure form. In 2018, a paper famously claimed that Bitcoin’s blockchain contained links to child pornography; at the time, critics dismissed it as sensationalism since only a few bytes of encoded data were involved and Core’s filters limited further abuse. But today we’re looking at a very different landscape. The data per block is increasing dramatically with the new policy. A concerned Bitcoiner known as “Bitcoin Mechanic” ( primal.net/p/nprofile1qqs8fl79rnpsz5x00xmvkvtd8g2u7ve2k2dr3lkfadyy4v24r4k3s4sh8dmel) recently warned that removing the filter “will draw unforeseen consequences,” meaning content like child pornography can appear on the Bitcoin blockchain” once v30 goes live. His point is straightforward: if you give bad actors the ability to inject large payloads, someone will inevitably push the worst kind of content into the system. And perversely, there’s a twisted incentive for them to do so: “Getting other people to store it for you is vastly preferable to storing it yourself,” Mechanic notes, what better way for criminals to disseminate vile material than piggyback on tens of thousands of innocent Bitcoin nodes?
Core developers have responded that these fears may be overblown. They often cite examples of other blockchains (for instance, Monero or Ethereum) that don’t have such data limits yet haven’t become overrun with illegal content. They stress that Bitcoin’s permissionless nature means anything could be written to it, but that doesn’t mean an epidemic of criminal data is imminent. Perhaps, but I would counter that Bitcoin’s global prominence and immutable design make it a uniquely attractive target for someone trying to cause chaos or discredit the system. It only takes one high-profile incident of truly heinous content on Bitcoin to unleash a regulatory crackdown. Remember, Bitcoin’s censorship-resistance cuts both ways: it empowers individuals, but it also neutralises traditional controls, which is exactly why governments get antsy when crimes enter the mix.
The legal implications of this are untested and scary. If a Bitcoin block contains illegal pornography or violent propaganda, could authorities argue that every node operator is technically in possession of contraband data? Some in the community worry that, yes, this could give governments a “perfect excuse to outlaw Bitcoin or make running a node illegal”. Even if that outcome is unlikely in jurisdictions that understand how Bitcoin works, the mere perception that Bitcoin is hosting criminal content would be a PR disaster. It would hand ammunition to anti-crypto politicians and could make regulators slam the brakes on adoption. As a Bitcoiner who wants to see this technology thrive, I find that risk unacceptable. Bitcoin’s social contract might be robust against internal dissent, but it’s not immune to external legal attack. Preserving Bitcoin’s integrity means ensuring it doesn’t become synonymous with “dark web file storage” in the public eye.
Embracing Self-Sovereignty: Why I Run Bitcoin Knots
My response to this situation has been guided by one of Bitcoin’s core principles: self-sovereignty. In essence, self-sovereignty means taking full ownership of your participation in the network, holding your own keys, and running your own node with the rules you choose. In the book I authored on Bitcoin and self-sovereign principles, I emphasised that running a node is more than a technical task; it’s an expression of personal agency and values. Now, faced with Bitcoin Core’s direction that I deeply disagree with, I’m putting that ethos into practice.
For the past four months, I have been running Bitcoin Knots instead of the standard Bitcoin Core software. Bitcoin Knots is a well-established alternative client (maintained by Luke Dashjr) that, in many ways, is identical to Core except for a few important differences, notably, Knots retains stricter limits on OP_RETURN data and gives the user full control over relay filters. In fact, Knots by default still caps OP_RETURN at 40 bytes (the old limit from years ago) and allows only one OP_RETURN output per transaction. It’s basically “Bitcoin Core, but with the spam filter intact.” By running Knots, my node will not relay or mine the kind of oversized data-storing transactions that Core v30 endorses. More importantly, it signals my support for a vision of Bitcoin that prioritises financial transactions over arbitrary data. Knots users (myself included) see ourselves as defending Bitcoin’s integrity from a controversial experiment. We are effectively saying, “Not on my node!” when it comes to turning Bitcoin into an uncensored data dump.
I’m far from alone in this choice. As mentioned, a substantial minority of node operators are switching to Knots or sticking with older Core versions. This grass roots movement is reminiscent of how users can enforce their preferences in Bitcoin – much like the User Activated Soft Fork (UASF) concept, node runners can ‘vote’ by choosing which software to run. If enough of us reject Core v30, it could create economic incentives for miners to think twice about stuffing blocks with junk that a portion of the network won’t relay or perhaps even accept. (To be clear, Knots today does accept blocks created under Core’s new rules – it’s not a hard fork. The divergence is in relay policy and default behaviour, not consensus rules. This is a fight being waged via network policy, not chain splits… at least not yet.)
Self-sovereignty also means accepting personal responsibility for what I support in the network. That extends beyond just the software I run. It also influences my choices as a customer and community member. In light of the OP_RETURN controversy, I have decided on a few concrete actions, which I’ll outline here:
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Running a “clean” node: I’ve migrated all my nodes to Bitcoin Knots and will continue to do so for the foreseeable future. This ensures that I am not propagating or validating illicit data beyond the absolute minimum required by consensus. If a bloated transaction or block crosses my node, Knots’ policies will treat it with the maximum strictness allowed (dropping it from mempool if possible, and certainly not relaying such transactions to peers). This is my way of keeping my corner of the Bitcoin network as clean of illicit content as possible. It’s a personal stand: I do not want even the chance of illegal material passing through my machine.
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Boycotting services that endorse Core v30: I am discontinuing my use of any exchanges, custodians, or Bitcoin companies that I know are upgrading to or support the Core v30 software without protest. For example, if a company like River Financial or a tech firm like Blockstream chooses to run Core v30 nodes (thus knowingly accepting the relay of unlimited content, illicit or otherwise), then I will not be doing business with them. Those organizations might trust their lawyers or regulators to sort out the fallout of hosting illicit data on their nodes – that’s their prerogative. But I cannot in good conscience support institutions that, in my view, are inviting a flood of abusive content onto the Bitcoin blockchain and risking its reputation. My money and support will go to those who keep Bitcoin robust and respectable.
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Advocating for a “clean” Bitcoin (even if it means a fork): Looking ahead, I suspect that other major players in the Bitcoin ecosystem share my concern, even if they aren’t voicing it loudly yet. Think of large public companies holding Bitcoin in their treasuries, or firms planning Bitcoin ETFs. The last thing these institutions want is to be entangled with a network that could inadvertently facilitate the spread of illegal content. It’s not hard to imagine some of them drawing a line: if Bitcoin’s protocol won’t address this problem, they might resort to extraordinary measures. This could include supporting a hard fork to create a “clean” version of Bitcoin that excises or filters out illicit material. BlackRock, for instance, is on the cusp of launching a spot Bitcoin ETF. In BlackRock’s own filings, they note that in the event of a fork, they have full discretion to decide which chain to consider the “real” Bitcoin for their fund.That means if a new fork gained momentum – say, a Bitcoin variant with strict protocol rules against arbitrary data – BlackRock could opt to adopt it for their ETF (or conversely, to abandon a chain that becomes too toxic). While this scenario sounds extreme, it’s entirely within the realm of possibility. The very fact that we’re discussing child pornography on the blockchain may prompt powerful stakeholders to assert control to protect their investments. I’m not actively calling for an immediate fork, that’s a complex, last-resort path, but I do believe that if Bitcoin Core’s path leads to legal quagmires, the market will find a way to course-correct, even if it means a chain split. My hope is that by raising awareness now, we can avert such drastic outcomes. But make no mistake: Bitcoin’s future must not include being a playground for criminal content, and I’ll support any serious effort to ensure that.
Bitcoin’s Future: Balancing Freedom and Responsibility
The controversy over OP_RETURN and illicit content forces an uncomfortable but necessary conversation about the future we want for Bitcoin. On one side is the ideal of total neutrality, Bitcoin as an unfilterable, permissionless ledger where “code is law” and even questionable data is just data. On the other side is the recognition that Bitcoin does not exist in a vacuum: if we undermine its primary use case as money or subject its participants to legal peril, we could kill the proverbial goose that lays the golden eggs. Finding the right balance is tricky. We cherish Bitcoin’s censorship-resistance precisely because it protects financial freedom and speech. Yet, does rejecting any filtering, even of grotesquely abusive content, truly serve the cause of freedom? Or does it hand enemies of Bitcoin the very weapon they need to attack it? These are challenging questions, and reasonable people in the community answer them differently.
For me, the answer comes back to self-sovereignty and consent. I did not sign up to store illicit images or arbitrary gigabytes of data on my node, that’s not the social contract under which I joined Bitcoin. My consent as a node operator matters. True decentralisation means we, the users get to collectively decide what the blockchain is for, by either running or not running certain code. It’s heartening to see that even Core developers acknowledge this in principle: “If Bitcoin Core’s contributors ever abandon [Bitcoin’s core] values… the community will switch to another node implementation that does it better,” wrote Gloria Zhao amidst the debate. I’d argue that forcing nodes to relay and store unlimited junk (with potentially ghastly contents) is a departure from the values that brought many of us to Bitcoin. And indeed, we’re seeing the community vote with its feet, or rather with its node software.
Moving forward, I believe Bitcoin will be stress-tested on this front. The coming months and years will reveal whether the network can accommodate new use-cases (like data inscriptions) without losing its soul – or whether a correction is needed. Perhaps Bitcoin Core’s gambit will pay off: maybe the “spam” will remain manageable, new pruning techniques will mitigate the bloat, and no criminal will attempt to abuse the blockchain’s openness. In that best case, my concerns would be eased (and I’d gladly acknowledge an overabundance of caution on my part). But if the worst case materialises, if obscene data starts showing up in blocks, if typical users find the chain clogged with non-financial data, if governments use this as a cudgel – then the community must be ready to respond decisively. Hard forks have happened before in Bitcoin’s history when values were at stake (recall the split that created Bitcoin Cash in 2017 over a blocksize dispute). A fork to preserve Bitcoin’s legal cleanliness and focused mission might become not just acceptable but essential to “future-proof” the network. And unlike a protocol tweak coming from a small group, a community or institution-driven fork would reflect a broad consensus that Bitcoin as it was is worth defending. BlackRock and other institutional players entering the space could ironically become allies in keeping Bitcoin safe for mainstream use – they will not tolerate holding an asset tainted by crime, so they have every incentive to back a solution, even if it’s a controversial one.
Conclusion: Upholding Bitcoin’s Integrity
In closing, my stance can be distilled to this: Bitcoin’s strength lies in our ability to choose and enforce the rules that best uphold the network’s purpose and integrity. As a self-sovereign participant, I choose to reject the notion that Bitcoin must accept everything in the name of “freedom,” especially when that freedom can be cynically exploited to Bitcoin’s detriment. Instead, I align with the principle that some judicious constraints, whether at the software policy level or the community social level, are necessary to keep Bitcoin healthy, useful, and legally accessible to all. This is a nuanced position, and it may be polarising. Some will accuse me of advocating “censorship” or betraying Bitcoin’s neutrality. I respect the purist viewpoint, but I humbly disagree in this case. Refusing to store illegal content is not tyranny; it’s common sense. We can defend freedom of transaction without turning Bitcoin into a sanctuary for the worst humanity has to offer.
In my book on self-sovereignty, I wrote that with great power comes great responsibility, running a Bitcoin node is indeed powerful, and it’s up to each of us to act responsibly with that power. Today, responsibility calls for vigilance about what changes we adopt. I am communicating these thoughts as part of my ongoing effort to ensure Bitcoin remains future-proof. “Future-proofing” Bitcoin doesn’t just mean scaling it or boosting hash rate; it also means safeguarding its social acceptance and moral foundation. By voicing dissent, by switching implementations, by potentially forking if needed, we the users are stress-testing Bitcoin’s resilience in exactly the way it was designed to be: from the bottom up.
Bitcoin’s story has always been about empowerment of the individual. This current saga, the Node Wars over OP_RETURN and content, is yet another chapter in that story. I, for one, am determined to see Bitcoin thrive as a tool of financial liberation, unsullied by association with illicit content. It may ruffle feathers now, but principled stances often do. As the saying goes, “Bitcoin is for enemies”, but that doesn’t mean we have to let enemies turn it against us. My hope is that through self-sovereign action and frank dialogue, we will navigate this challenge and emerge with a Bitcoin network that is both freer and more secure, a network that can confidently serve the world for decades to come, without any shadow of disgrace on its ledger.
The choice is in front of us. By October 2025, Bitcoin Core v30 will normalise the relaying of arbitrary, potentially illicit content across the network. If we do nothing, if we keep quiet, then we silently consent to this shift. As Bitcoiners, we must ask ourselves: do we want our blockchain remembered as the foundation of sound money, or as a storage ground for abuse?
I’ve made my decision, I run Bitcoin Knots, I reject services that endorse Core v30, and I will defend a “clean” Bitcoin that remains worthy of global trust. The question is: what kind of Bitcoin are you willing to stand behind?