Bitcoin proposal to curb spam with a temporary soft fork sparks debate among developers

The growing debate between Bitcoin developers over how much arbitrary data should be allowed on the world's most valuable blockchain has resulted in a controversial new proposal: Bitcoin Improvement Proposal 444, or BIP-444. 

The proposal, published Friday night, comes in the wake of Bitcoin Core's v30 update, which effectively uncapped the amount of data that can be added to a typical Bitcoin transaction using OP_RETURN, so long as appropriate fees are paid. The update went live this month, despite fierce debate over the byte size limit change, though it has faced slow adoption, with about 6.3% of reachable nodes using the software, according to Bitnodes data . 

Now, some Bitcoiners are seeking to undo that change, and restrict all other methods to add arbitrary data to Bitcoin transactions, expressing concerns that illegal content uploaded to Bitcoin, like child sexual abuse material, could create legal liabilities for node operators. 

"If the blockchain contains content that is illegal to possess or distribute, node operators are forced to choose between violating the law (or their conscience) or shutting down their node," the proposal states . "This unacceptable dilemma directly undermines the incentive to validate, leading to inevitable centralization and posing an existential threat to Bitcoin's security model."

Under the terms of the proposal, OP_RETURN outputs would be limited to 83 bytes and most other scriptPubKeys would be capped at 34 bytes, effectively choking off outputs that contain large scripts or data blobs. The proposal would also cap the size of individual data pushes, invalidate currently unused or undefined script versions to prevent bypassing the restrictions, cap the size of embedded Merkle trees in Taproot outputs, and outlaw OP_IF inside Tapscripts, directly killing the Ordinals inscription method. 

These changes would lead to a soft fork, in which previously valid transactions would be made invalid, but the proposal calls for the change to be temporary, lasting around a year. The break would give Bitcoin developers enough time to evaluate and implement alternate approaches to arbitrary data storage on the blockchain. 

"The explicitly temporary nature of the softfork further reinforces that this is a targeted intervention to mitigate a specific crisis, not a commitment or proposal of a new direction of development," the proposal states.  

The proposal was written by "Dathon Ohm," who joined GitHub and X in the days before submitting the proposal and shows no apparent Bitcoin development history. The Block could not immediately reach Ohm for comment on the proposal. 

Longtime Bitcoin developer Luke Dashjr, known for his anti-Ordinals advocacy, has expressed his support for the proposal, noting on X that it is "on track with no technical objections." 

"This isn't intended to be an ideal solution, only good enough and super simple to buy time to design a long term solution," Dashjr wrote on X Sunday. Dashjr also denied authoring the proposal in other posts.

Critics of the proposal generally argue that arbitrary data in Bitcoin has existed since the network's genesis block , and that choking off methods used to add arbitrary data amounts to censorship and violates Bitcoin's core principle of permissionless use. X user Leonidas, a prominent figure in the Ordinals community, claimed in September that miners and mining pools representing more than half of Bitcoin's hash rate told him they would accept any consensus valid Bitcoin transactions with appropriate fees attached. 

"There is no meaningful difference between normalizing the censorship of JPEG or memecoin transactions and normalizing the censorship of certain monetary transactions by nation-states," Leonidas wrote. "Both would set very dangerous precedents."

Jameson Lopp , co-founder and chief security officer of Bitcoin secure storage firm Casa, made a number of critical comments on the proposal, noting that the proposal does not define which content is legally or morally questionable, and adding that legal experts disagree on the liability node operators would face. 

"By running a node you consent to the consensus rules of the network. If you don't consent, you can simply not run a node," Lopp wrote in one comment . The Block could not immediately reach Lopp or Dashjr for comment. 

The proposal has not yet been distributed to the Bitcoin Development Mailing List, a necessary step for draft BIPs to gather more feedback and move towards acceptance, though the proposal has generated a flurry of comments and debate on X and other forums.