The Script Army Knife
OP_CHECKCONTRACTVERIFY
OP_CAT
OP_CHECKSIGFROMSTACK
OP_AMOUNT
OP_CHECKTEMPLATEVERIFY
This is a minimal set of opcodes that can implement virtually any of the interesting constructions that I've seen discussed and researched in the last few years.
In fact, I'd challenge anyone to find a compelling construction that cannot be implemented with these opcodes.
The exception is of course some extremely complex operation that cannot fit in a block (or is impractically large) without a custom opcode. Examples are Snark verifiers, BLS signatures, quantum-resistant signatures, other advanced crypto, etc.).
However, for those advanced use cases, MATT fraud proofs (enabled by CCV+CAT) might be a viable substitute for many applications, allowing to get the benefits of those constructions on layer 2 without exposing layer 1 to cryptography that is considered too novel.
Each of these opcodes is simple, has at least a draft implementation, and they are all very composable with each other, and with any possible future Script updates.
This is a minimal set of opcodes that can implement virtually any of the interesting constructions that I've seen discussed and researched in the last few years.
In fact, I'd challenge anyone to find a compelling construction that cannot be implemented with these opcodes.
The exception is of course some extremely complex operation that cannot fit in a block (or is impractically large) without a custom opcode. Examples are Snark verifiers, BLS signatures, quantum-resistant signatures, other advanced crypto, etc.).
However, for those advanced use cases, MATT fraud proofs (enabled by CCV+CAT) might be a viable substitute for many applications, allowing to get the benefits of those constructions on layer 2 without exposing layer 1 to cryptography that is considered too novel.
Each of these opcodes is simple, has at least a draft implementation, and they are all very composable with each other, and with any possible future Script updates.