First, I'd like to thank
@1440000bytes for the excellent compilation of covenants. Here I'll briefly outline these covenants and explain the attitudes expressed in the table.
OP_CTV represents the simplest way to make UTXO spending predictable. It inspired ideas about implementing Shared UTXO on Bitcoin and unilateral exit mechanisms, including the controversial congestion control tree. While some consider it insufficiently flexible, I believe it's adequately effective and simple, thus posing minimal potential risk to Bitcoin. Therefore, I lean towards favoring CTV.
Regarding OP_CSFS, I first encountered it while reading about CTV use cases, discovering its potential to combine with CTV for efficient non-interactive payment protocols. I believe it has more interesting use cases, hence my "Acceptable" rating.
OP_PAIRCOMMIT is an interesting example because many script program designs using OP_CAT operate similarly to OP_PAIRCOMMIT: hashing after concatenating elements. However, CAT has been promoted for a long time, and we shouldn't limit ourselves to just this usage in the future.
OP_INTERNALKEY designs have been discussed extensively historically, but we understand they only solve part of the UTXO introspection issue. If we only get one upgrade opportunity every four years, this seems too wasteful.
OP_CAT was originally designed to concatenate two elements but unexpectedly achieved complete UTXO introspection of Bitcoin through the Schnorr trick, making CAT representative of universal covenants. I recommend reviewing
@weikengchen's cases like state caboose to understand an alternative implementation of MATT-like concepts.
OP_CCV prompted many to consider implementing native applications on Bitcoin. MATT's forward-thinking approach is admirable, but its design is somewhat rigid. Perhaps we'll develop better solutions in the future.
Compared to CTV's commitment to fixed UTXO fields, OP_TXHASH allows users to choose fields for commitment construction. However, this adds complexity: we must decide which fields can enter the stack and how to represent field selection. I believe introducing TxHash would only bring more controversy and issues. Nevertheless, its design is undeniably cool.
APO's past application in Eltoo actually couldn't bring a better future for Bitcoin, as I've detailed in my article. Those interested can read more at the
medium.com/@discocolabs/the-…。