OP_CHECKCONTRACTVERIFY is BIP-443.
When I presented MATT at the first @btcazores
in September 2022, it was just a concept: a minimal covenant with maximal power. While the covenant was straightforward, what a good implementation would look like was far from clear.
Then came James O'Beirne's OP_VAULT proposal - a narrower, practical use case for a covenant. And yet, it resonated: the underlying need was the same as in MATT. Both required a way for coins to carry state (data) from input to output.
If two very different problems point to the same technical tool, maybe that tool is a solid foundation.
CCV implements that foundation.
CCV is not made for vaults, but it enables them (alone, or supercharged with CHECKTEMPLATEVERIFY).
CCV is not "MATT's opcode", but it's the main building block.
CCV is also what bridges like BitVMs are simulating with workarounds like Lamport Signatures: updating the state. It makes large part of their on-chain footprint redundant, and greatly simplifies their design.
There's no more for cabooses, CatVMs, ColliderVMs. Script will finally have an expressive primitive for carrying state in UTXOs.
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There is still a lot of work to do. The implementation needs to be reviewed and improved, ideally to be made ready for signet. More tooling needs to be developed. More work is necessary to assess what combinations of opcodes work best for a soft-fork.
CCV has no sponsors and no funding.
Can you help?
Find me at @The Bitcoin Conference in Vegas and let's keep the ball rolling.