An effort to introduce Ethereum-style smart contract capabilities to Bitcoin, known as OP_CAT, has been given an official designation in the form of BIP (Bitcoin Improvement Proposal) number 347. This marks the beginning of the process to implement this proposed software enhancement.
Having a BIP number assigned to a proposal doesn’t imply community approval, Ethan Heilman explained during an interview. Instead, it simplifies the conversation and development process by providing a distinct numerical label that all parties can agree upon.
Put simply, receiving assignment for BIP 347 implies that the contentious debate on this proposal can now be carried out more seriously and intensively.
The Bitcoin network has two opposing groups. One group advocates for keeping it primarily as a platform for monetary transactions. The other group aims to develop innovative applications on the network, with supporters of OP_CAT being a small segment of this group.
OP_CAT is a coding shortcut with a rich background in Bitcoin communities. Introduced among the initial set of op-codes by Satoshi Nakamoto around the inception of Bitcoin, it was later discarded in 2010 due to concerns over excessive memory consumption and potential security risks.
In more recent times, there has been renewed interest among Bitcoin advocates in employing OP_CAT as a means to expand Bitcoin’s capabilities, following the launch of the Ordinals protocol. Alternative suggestions put forth by some include Jeremy Rubin’s CTV and advanced scaling platforms such as Stacks and Ark.
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In 2022, Heilman and Sabouri initiated research on restoring OP_CAT in Bitcoin. They suggested introducing it through a soft fork on the mailing list approximately one year later, utilizing a backward-compatible approach to avoid altering the existing “OP_SUCCESS126” code substantially. Instead of requiring a hard fork, they planned to reinterpret and expand upon this existing code.
Should the proposition be approved, OP_CAT covenants would facilitate the development of advanced applications and multi-signature arrangements on Bitcoin. This is accomplished through the incorporation of “covenants,” which are essentially rules that can be set to govern how a particular transaction behaves, into the Bitcoin system.
“Bitcoin gives users the ability to establish conditions for spending their bitcoins. On the other hand, CAT merely combines two values into one. For instance, if you have ‘abc’ and ‘def,’ CAT creates a new value ‘abcdef.’ However, this simple action cannot be achieved presently,” Heilman explained, further clarifying that “CAT” is simply an abbreviation for the term “concatenate.”
Once the community is satisfied with the software’s performance, we will prepare a Pull Request (PR) for submission into bitcoin-core. The next phase brings excitement as the focus shifts from “is the software accurate?” to “does the Bitcoin community approve of OP_CAT?” This could be a swift process or a lengthy one. (Heilman’s words, paraphrased)
Eric Wall and Udi Wertheimer, founders of renowned Ordinals project Taproot Wizards, have been strong advocates for OP_CAT. They spearheaded the Quantum Cats inscriptions project as a promotional effort for Heilman and Sabouri’s proposal.
Quantum Cats has gained significant popularity as an inscription project, but OP_CAT, which is a key component of it, remains controversial among some in the Bitcoin community. There are rumors that the proposal from Heilman and Sabouri, who submitted it several months ago, has been delayed in obtaining approval due to skepticism from one BIP editor and Bitcoin Core developer, Luke Dashjr. However, he is not alone in expressing such doubts about recent experimentation on the blockchain.
On Mondays, five new BIP editors for Bitcoin were chosen by the community and assigned numbers according to GitHub. One of these editors, known as Roasbeef, was responsible for assigning OP_CAT’s BIP number.
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Heilman expressed that with OP_CAT having been assigned a BIP (Bitcoin Improvement Proposal) number, it is now the responsibility of the community to decide if it’s worth pursuing further.
In my own opinion, I intend to step back from the discussion and allow the community to decide whether they support OP_CAT or not. I don’t intend to participate in the debate unless there are technical queries that require my input.