Hi list, As we're working toward numbering and merge for the CHECKSIGFROMSTACK (CSFS) BIP, there are 2 open questions[1] that may be worth resolving before it is merged as a draft:
* Should CHECKSIGFROMSTACKVERIFY (CSFSV) be added to pre-tapscript? The proposed opcode always evaluates BIP340 Schnorr signatures regardless of script version, so making it available in earlier script versions makes Schnorr signatures available on those script versions for certain use cases. My personal thinking in initially including CSFSV in earlier script versions was basically that it's compatible with NOP forking, so why not. Because LNHANCE includes CTV which is designed as a NOP compatible upgrade, also including CSFSV fits well with CTV. The other side of the argument is that we shouldn't include compatibility with earlier script versions unless there's a concrete benefit to doing so. For CTV, the possibility of bare CTV is a compelling reason to add it to earlier script versions, but there's not a similarly compelling reason to include CSFSV. Using a scarce NOP to provide Schnorr signed commitments to earlier scripts may not be worthwhile. * Should we include CHECKSIGFROMSTACKADD? Obviously, if script multisig is going to be a common use case for checking signatures on stack data CHECKSIGFROMSTACKADD simplifies the corresponding scripts by a few WU per key. As MuSig2 and FROST are progressing in standardization and implementation, I do not expect script multisig to be a dominant use for these opcodes, so I did not include CSFSA initially. Here the argument is somewhat the inverse of CSFSV on legacy: We have many OP_SUCCESSes available, so the cost of allocating one for CSFSA is low, and the benefit is that making script multisigs with CSFSA (such as those produced by miniscript) is simpler and less error prone. -- I would love to hear thoughts about both of these questions from the list, and will update the BIP and implementations of CSFS(V/A) based on your feedback. Thanks much! --Brandon [1]: https://github.com/bitcoin/bips/pull/1535#issuecomment-2111195930 -- You received this message because you are subscribed to the Google Groups "Bitcoin Development Mailing List" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion visit https://groups.google.com/d/msgid/bitcoindev/ZzZziZOy4IrTNbNG%40console.
