Author: Russell O'Connor 2022-05-11 19:41:16
Published on: 2022-05-11T19:41:16+00:00
In a discussion on the bitcoin-dev mailing list, ZmnSCPxj reminded readers that `OP_CAT` alone does not enable covenants, whether recursive or not. However, it was suggested that using `OP_CAT` in tapscript enables non-recursive covenants, and it is unknown whether it can enable recursive covenants. Andrew Poelstra demonstrated how to use `OP_CAT` to get the sighash value + 1 onto the stack and then use SHA256 to get the signed transaction data onto the stack, which could be used to build functionality similar to OP_CTV through introspection. The missing pieces for enabling recursive covenants involve transforming a scriptpubkey into a taproot address, which involves some tweaking. Poelstra has suggested hijacking the ECDSA checksig operation from a parallel, legacy input to perform this tweaking calculation, but no one has yet achieved this feat.
Updated on: 2023-06-15T20:34:39.644883+00:00