If approved, OP_CAT will introduce drastic changes to the Bitcoin network, including covenants, ZK-rollups, and even Bitcoin-native layer 2 networks.
StarkWare CEO Eli Ben Sasson says he expects OP_CAT — a major upgrade to the Bitcoin network — to go live sometime within the next 12 months.
Speaking to Cointelegraph at Devcon 2024 in Thailand, Ben-Sasson says the introduction of OP_CAT will enable a suite of new functionality on Bitcoin, including “covenants, ZK-rollups and layer 2 networks.”
Notably, the introduction of OP_CAT will see Starknet become the first layer-2 network to settle natively on both Bitcoin and Ethereum.
While OP_CAT is an undeniably complex update to Bitcoin, with a multifaceted suite of potential upgrades, Ben-Sasson says the concept behind it is actually quite simple.
“OP_CAT adds one button to this scientific calculator, a button that can ‘concatenate’ or merge together to strings of characters. So this thing that just allows you to concatenate two strings […] and lets you use the Bitcoin calculator to inspect files, run programs, read long things, and operate on them,” Ben-Sasson said.
OP_CAT — short for “operation code concatenate” — refers to a string of code originally implemented into the Bitcoin network by Satoshi Nakamoto. However, Nakamoto was initially worried that OP_CAT could expose the Bitcoin network to security risks and scrubbed it from the active opcodes in 2010 as part of a broader effort to make Bitcoin simpler and more robust.
But in October 2023, cryptographer Ethan Heilman and Botanix Labs lead engineer Armin Sabouri breathed fresh life into the idea of OP_CAT, introducing a proposal to re-activate the opcode by way of a soft fork to the Bitcoin network.
Ben-Sasson says the goal behind OP_CAT and StarkWare’s foray into the Bitcoin L2 space is to allow Bitcoin to achieve its “original mission and purpose.”
“[It would see Bitcoin become] a payment network, which currently is just too expensive to be that. So you can buy your cup of coffee without needing to spend a fee that is 10 times that cup of coffee,” Ben-Sasson said.
The StarkWare CEO also spoke about building a Bitcoin L2 at the Bitcoin Next conference in Bangkok on Nov. 13.
Several experts told Cointelegraph that the introduction of OP_CAT could see Bitcoin eventually overtake Ethereum in terms of decentralized finance activity and volume.
While there has been a massive uptick in the number of Bitcoin “sidechains” that are often categorized as Bitcoin L2s, they’re not what experts call true layer-2 networks.
This is because sidechains don’t settle natively to the Bitcoin network, often using a two-way peg such as Stacks’ proof-of-transfer model or a bridging mechanism.
Lachlan Feeney, the founder of Web3 development firm Labrys, told Cointelegraph that the problem with sidechains is that they don’t offer the famously conservative Bitcoin OGs the necessary amount of security or innovation to justify putting their idle Bitcoin to work.