For future segwit versions, I think it would be good add a few things
to the sighash by default that were overlooked in BIP143:
* Committing to the absolute transaction fee (in addition to just the
amount being spent in each input) would categorically remove concerns
about wallets lying about fees t...
## WCN Episode Summary: SIGHASH_NOINPUT (2019-03-09)
This WCN episode summarized a complex discussion from the Bitcoin developer mailing list regarding the `SIGHASH_NOINPUT` proposal, initiated by Peter Wolley in November 2018. The goal is to improve the efficiency of the Lightning Network and enhance security, potentially requiring a soft fork.
Main Topics:
- SIGHASH_NOINPUT Refinement: Focused on improving the "sick hash, no input" proposal.
- Optional Transaction Details: Exploring a system for making certain transaction details optional during signing, allowing for script changes post-signature.
- Caching Flags & Opcode: Introducing "Cache No Input," "Cache No Fee," "Cache Script Mask," and a new opcode ("op mask") to explicitly define what parts of a transaction can be altered after signing.
- Explicit Commitment: Emphasizing the importance of explicitly committing to transaction fees and script pop key within the hash.
- Rebinding Attacks & Hardware Wallets: Addressing concerns about rebinding attacks and ensuring hardware wallets (like Coldcard) can verify script details.
- BIPsick hash two: A proposal to simplify signatures by dropping SIGHASH bytes and using intermediary hashes.
Key Quotes:
- The discussion centered around "explicitly stating what is being signed in a transaction."
- The proposal aims to "simplify signatures" and reduce computational overhead.
- Concerns were raised about hardware wallets' ability to verify script details.
People Mentioned:
Peter Wolley, Anthony Towns, Christian Decker, Jonas Lu, Russell O'Connor, Bob McEller, Jonas Lau, "llet."
Bitcoin Price: Not mentioned in the provided summaries.
This discussion highlighted the intricacies of Bitcoin's scripting language and the need for careful consideration of security, privacy, and efficiency when implementing changes.