Op_cat is the operation code (opcode) of the Bitcoin scripting system introduced by Satoshi when he released Bitcoin. It allows two stack elements to be connected into one element, bringing programmability and composability to Bitcoin and making the Bitcoin ecosystem more sustainable. More possibilities emerge. This opcode existed in early versions of Bitcoin, but was removed by the Bitcoin Core community because its script size was unlimited and would place additional storage burden on Bitcoin nodes. Now, as Taproot’s upgrade introduces a script size limit (520 bytes), OP_CAT is once again the focus of discussion and is expected to be implemented. Bitcoin researcher Ethan Heilman submitted a Bitcoin Improvement Proposal (BIP) to the Bitcoin-Dev mailing list, proposing that the OP_CAT opcode be added to Bitcoin’s scripting language. However, the introduction and implementation of OP_CAT does not come without costs. It would still increase the complexity of the Bitcoin scripting language and introduce new potential risks (such as infinite recursion or transaction size inflation).
Until the final results come out, OP_CAT is like Schrödinger’s cat, in a quantum state. Will you support the new life of OP_CAT?
Taproot Wizards is launching Quantum Cats, a new NFT collection on the Bitcoin blockchain for this purpose. It’s fun, let’s make our own choices for this moment, whether it’s a living cat or a dead cat, it will eventually leave a permanent record in the history of Bitcoin development.