In recent weeks, an OP_Return debate has exploded in the Bitcoin industry and has now invaded most of the dialogue space in the industry. This topic is rich and complex, and many people have strong opinions on the matter.
OP_Return is an OPCODE in Bitcoin’s scripting language used to store metadata or arbitrary data that is not related to Bitcoin transaction verification, so it can be pruned by node runners without too many problems, allowing spam to be managed more effectively while also providing developers with a controlled environment for permalinks.
A method to reduce hazards to spam issues, the OP_Return controversy was recently triggered by a pull request submitted by Peter Todd to the Bitcoin core repository. The update’s supporters aim to undo the amount of any data that can be placed in the OP_Return by deleting the MEMPOOL policy rule that limits it to 80 bytes. Therefore, this moves the limit to the upper limit of the common block size of 1MB non-isolated data. They believe that the restriction is no longer effective in stopping spam, instead, it leads to more harmful behavior, such as populating data in UTXOS, which hurts node runners.
Additionally, the proposal removes the DataCarrier flag, a configuration option that allows node runners to select which transactions to filter from their local mempool based on any data carried by OP_Return.
The opposition, led by Luke Dashjr, not only wanted to keep the OP_Return limit in place and keep the size of DataCarrier, but also proposed further restrictions on arbitrary data and Bitcoin “non-currency” transactions.
Both camps generally agree that arbitrary data on Bitcoin is a bad thing for the network. They also agree that filters cannot filter all types of spam. What they disagree with is the effectiveness of these filters in mitigating spam. They also disagree with the consequences of applying or removing these filters from the network, the impact on the cost of running nodes, and the impact on mining centralization.
Author’s Note: Of course, not all supporters agree with all arguments against La’s arguments, and not all opponents agree with all arguments against it. This is just a general overview of the various parameters in it (maybe incomplete).
While Peter Todd’s leadership has been supported by many Bitcoin core contributors, the removal of OP_Return restriction represents a way to reduce hazards to spam issues and arbitrary data on Bitcoin.
Todd believes that the current OP_Return restrictions were initially placed a decade ago to allow spammers to provide a secure, controlled space for arbitrary data, as companies and enthusiasts have developed the purpose of private Mumbai directly to Mina (such as Mara’s Slipstream), such as bypassing Mara’s Slipstream and bypassing Mempool policies.
After Satoshi Nakamoto left, the OP_Return restriction was placed in place to protect the network from similar spam, but in a very different era, blocks rarely satisfy, let alone have a high-cost environment. There are also few tools for trimming, and there are no tools, and the software is inefficient. Many optimizations have been implemented over the past decade, and their cumulative impact has affected this debate.
So when it is first created, the OP_Return limit is more efficient and harder to bypass. Today, NFT and arbitrary data enthusiasts have ambitious projects, and the current MEMPOOL limit puts pressure on the OP_Return space, which has turned to the help of stuffing arbitrary data into the UTXO cluster. With op_return or segwit spaces can be reasonably pruned from nodes, UTXO sets are usually saved in RAM, which is the most expensive form of memory. The UTXO set needs to be processed by the node to verify the supply of coins and be able to verify the integrity of the new transaction, which is the basic paragraph of running a node, without that node losing most of its value proposition. Therefore, UTXO data filling impairs the decentralization of the Bitcoin network by adding initial block downloads, overall synchronization time and hardware requirements, thus imposing huge costs on node runners.
Finally, supporters believe that miners are “rational economic actors,” an economic term that means that to keep their lives in a highly competitive market, miners need to optimize profits as much as possible. So if the mining consensus-Walid non-standard transactions give them an advantage, they will accept it.
Back in 2023, Luke Dashjr proposed a change that attempted to apply the DataCarrier Mempool policy to Segwit and Taproot arbitrary data, such as inscriptions, further limiting spammers’ options. Peter Todd opposes PR and explains: “The withdrawal request targets transactions that are an important source of income for miners. Miners are unlikely to give up on that source of income. Reviewing these transactions is only to encourage the development of private Mumbai – the harm to small miners – while reducing the cost estimates are reliable.”
Todd’s pull request does one thing in addition to removing the op_return limit: it also removes the datacarrier flag from the configuration options of the node operator. Users of Bitcoin Core Node Software can control their transactions relayed through nodes based on a configuration option called the DataCarrier flag, which specifically looks at the amount of data inside OP_Return, and the default data today is 80 arbitrary data.
Supporters believe that the flags are now outdated, even through MEMPOOL Policy, even if they are “non-standard”, such as the generality of tools such as the Slipstream program of mining pool Mara or Todd Libre.
Consensus – valid non-standard transactions conflict with MEMPOOL policy rules such as OP_Return restrictions, but do not violate any consensus rules, so if you can simply understand miners, you can directly include miners in Bitcoin. Supporters argue that such systems are outdated and controversial filters, which makes the DataCarrier flag irrelevant, especially with the default OP_Return size limit.
Supporters believe that the logo only gives the user a illusion of control and is a “foot gun” which is a dangerous and abuse-prone tool in which the user has no utility to the user.
Finally, deleting the data carrier flag within the limits of OP_RETURN can eliminate recurring conflicts and controversy at the Bitcoin core, because the filter-backed Bitcoin maximists are not the only ones who have opinions on the matter, nor are they able to assemble the Internet to oppose pull requests.
In 2023, a pull request was made to Bitcoin Core, which attempts to change the exposed Multisig transactions to change the default Mempool strategy. This is the old standard used by the NFT protocol (such as stamps, etc.) today to ensure that its arbitrary data can easily become a chain, and better yet, cannot be easily trimmed. Pull requests quickly transformed into an internet flame war between “spapers” and change supporters, integrating it into the Bitcoin core in a similar way to Todd’s pull requests.
They believe that by removing the DataCarrier logo, supporters think it’s irrelevant, that such dramas can be placed on the bed, and Bitcoin core contributors can continue to explore other more pressing issues.
The opposition – commonly known as filter – is led by longtime Bitcoin core contributor Luke Dashjr, who believes that removing the OP_Return size limit is a surrender to spammers, rather than a perfect filter needed, but rather a company or project that only needs filtering to a company or project that wants to build a system of arbitrary data on Bitcoin. The message is: go build somewhere else or find a better way.
They think Bitcoin is just a network used for currency transactions, and anything other than that definition is spam. In their view, currency transactions are Bitcoin transactions that seek only to transfer value counted in Bitcoin between two users, while goods and services transfer the rewards of the chain.
According to Chris Guida, a thunder developer and supporter of Bitcoin’s trough, there are about two formal definitions of currency transactions on Bitcoin.
“I think there are two different definitions for valid definitions: one with transactions that are actually using bitcoin as payment rails, rather than involving the database of scammy’products,” refers to NFTS, adding “effectively, the other definition is that 40/80 bytes in 40/80 bytes in op_return in op_return none of these standards apply.
Above Bitcoin, NFT transactions or arbitrary data used to fix the Layer 2 protocol are not considered currency transactions in this sense and are therefore considered spam, even if these Layer 2 may be conducting various financial transactions.
Furthermore, the filter believes that Bitcoin core should actively look for ways to prevent this behavior. They believe that spammers who turn to UTXO fillings are evidence that filters work, because stress effectively leads them to find ways to other spam networks. In other words, if the filter doesn’t work, spammers won’t look for more expensive terrain to build their spam systems, such as UTXO collections.
Therefore, not only should the limit of OP_RETENT should be preserved, but it should probably be further narrowed down, perhaps dating back to history 40 bytes. In addition, the data carrier flag should be extended to control isolated witness and taproot transactions, neither of which nor Tapirut transactions are used for arbitrary data until block size limits and exploited by spammers, the most outstanding of which is the inscription.
Finally, the filter confirms that systems like Todd’s Libre relay or Mara’s Slipstream can be done in a variety of ways, and that if the Bitcoin core continues to use its current development path, they won’t simply collapse. The result is growing interest in Bitcoin junctions, an alternative implementation of Bitcoin maintained by Luke Dashjr and others to enable Bitcoin users to run their own filters when they see fit. As of writing, more than 5% of Bitcoin nodes are running bitcoin bonds according to Luke’s network analysis.
Filters and Bitcoin junctions are restored in principle to defend the Datacarrier logo. They believe that there are enough numbers that coordinated node runners have a way to successfully filter a set of spam and even argue for extensions of content managed by DataCarrier Flag, as shown in the 2023 Luke Dashjr pull request. In it, Segwit and Taproot arbitrary data storage functions will also be limited by the DataCarrier flag controlled by the node’s operation; they are not currently.
This, in particular, resonates with many people, is Bitcoin implemented from an increasing number of bitcoin stakes, including changes to such Mempool strategy while keeping all other bitcoin core codes intact.
Some Bitcoin junction proponents, such as Chris Guida, have begun talking about user-controlled relay strategies or “modular filters” that can be created by refactoring the Mempool policy code and updated to follow certain proactively managed templates – an automatic spam filter filter algorithm that users can choose from among providers.
On X, he argues that “usually claiming to filter spam is a “cat and mouse game” and that filters are at a disadvantage to some extent.
I think this is ridiculous. We can create filters as quickly as the new functional token Metaprotocols, and even create new TX formats before hitting Mainnet. ”
While even filters recognize that spam controls have limitations, they insist that hostile environments of software systems and business models associated with spam are a good thing and need maintenance to prevent bad behavior, even the more sensitive version will still pay miners directly and make them pay.
