One of the Bitcoin Core developers, Peter Todd, has proposed lifting restrictions on the use of OP_RETURN, a special mechanism for publishing data on the blockchain. In a commentary for Incrypted, he described his vision of the process.

Currently, Bitcoin Core allows only one OP_RETURN output per transaction with a limit of 80 bytes of data. Todd believes that these restrictions are outdated and harm the network more than they protect it.

According to Todd, many modern protocols, such as Citrea, already publish data on the blockchain, but due to technical limitations, they are forced to use “fake” transaction outputs that remain in the UTXO set forever, making it difficult for nodes to operate. The use of OP_RETURN avoids this, as such outputs are not stored in UTXO.

“We want those use-cases to use OP_RETURN instead, which is a data publication mechanism that doesn’t go into the UTXO set,” Todd explained.

The Incrypted team noted critics’ concerns about the removal of restrictions that would allow large infrastructure players to fill blocks with data, increasing the hardware requirements for running a full node. However, Todd called these fears unfounded:

“Those concerns are bogus. People who want to can easily get blocks mined with whatever they want in them. All we’re doing is making one specific method of publishing data a little easier, to try to entice people into using it rather than a more harmful mechanism.”

Todd emphasised that this change will not open up new opportunities for protocols or the network, as all of these applications can already be built on top of bitcoin. The goal is to encourage the use of a less harmful mechanism for publishing data.

“All we’re doing is trying to entice applications to use a specific mechanism to publish data to use a different mechanism that is less harmful to the network as a whole,” Todd said.

Furthermore, he does not believe that this change has a long-term connection to the potential expansion of the Bitcoin scripting language. Systems that use data publishing, such as Citrea, don’t need blockchain scripts because they build their consensus from scratch, solely from published data.

“Those systems just don’t use scripts in any meaningful way to begin with,” Todd said.

As a reminder, Peter Todd has confirmed his participation in the largest conference in Ukraine — Incrypted Conference 2025, which will take place on 14 June 2025.