The post Bitcoin’s Battle Over Arbitrary Data appeared on BitcoinEthereumNews.com.

An OP_RETURN debate flared up in the Bitcoin industry in recent weeks and has by now invaded most conversation spaces within the industry. The 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 meta data or arbitrary data that is not relevant for bitcoin transaction validation, as such can be pruned by node runners without much issue, enabling more efficient management of spam while also giving developers a controlled environment to anchor data on chain.  Taking a harm reduction approach to the problem of spam, the OP_RETURN controversy was recently triggered by a pull request submitted by Peter Todd to the Bitcoin Core repository. Proponents of the update seek to uncap the amount of arbitrary data that can be placed in the OP_RETURN by removing the mempool policy rule that restricts it to 80 bytes. By consequence, this moves the limit up to the consensus block size cap of 1MB of non-SegWit data. They argue that this limit is no longer effective at stopping spam and, on the contrary, is leading to more harmful behaviors such as stuffing data in UTXOs, which harm node runners. Furthermore, the proposal removed the datacarrier flag, a configuration option that allowed node runners to choose which transactions to filter from their local mempool based on how much arbitrary data the OP_RETURN carried. The opposition, led by Luke Dashjr, not only wants to keep the OP_RETURN limit in place and retain the datacarrier size but proposes further mempool policy restrictions on arbitrary data and “non-monetary” transactions on Bitcoin. Both camps generally agree that arbitrary data on Bitcoin is a bad thing for the network. They also agree that filters cannot possibly filter all kinds of spam. What they disagree…

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Filed under: News - @ May 13, 2025 3:28 pm