Elements Hardfork Wishlist

[stevenroose]

Just for record keeping a wishlist of hardfork changes that might be considered for Liquid v2.

• remove CHECKSIGFROMSTACK (keep CHECKSIGFROMSTACKVERIFY) (CHECKSIGFROMSTACK has VERIFY semantics #202)
• Fix Non-witness transactions cannot include issuances #473: " Non-witness transactions cannot include issuances"
• Taproot script with threshhold support in wallet (SF actually, but hey it's a lit)
• Bulletproof rangeproofs, including generalized sidechannel in witness data
• Make block header CProof witness data stack of bytes not script [HF] CProof::solution should be a list of byte-vectors, not a script #404
• Fix reissuance tokens can not be exercised from unblinded outputs #259: "reissuance tokens can not be exercised from unblinded outputs"
• ComputeWitnessHash should, like in Core, compute the wtxid instead of withash
• relax MAX_MONEY constraint

2022-02-10:

• more sighash flags on txes with version 3 or higher (or segwit versions 2 or higher, or whatever)

[instagibbs]

• Fix Non-witness transactions cannot include issuances #473
• Taproot script with threshhold support in wallet (SF actually, but hey it's a lit)
• Bulletproof rangeproofs, including generalized sidechannel in witness data
• Make block header CProof witness data stack of bytes not script [HF] CProof::solution should be a list of byte-vectors, not a script #404

[instagibbs]

• Fix reissuance tokens can not be exercised from unblinded outputs #259

[stevenroose]

You can edit inline in the top comment :)

[apoelstra]

• support schnorr/taproot in block headers for CProof
• add sighashflag to signatures in CProof solutions

[instagibbs]

Restrict peg-in claim_script to native segwit scriptPubKey.

[instagibbs]

Going over all issues that are more slam-dunk:

tx-related issues:
Remove potential signature malleability over issuance inputs #559
put peg-in-ness under signature digest #553
Non-witness transactions cannot include issuances #473

chainstate-related issues:
be more systematic in avoiding parent-child chain txid collisions #551

blockheader-related issues:
Consensus parameter commitment tracking issue #534 (dynafed fixes this)
[HF] CProof::solution should be a list of byte-vectors, not a script #404 (dynafed fixes this)

#473 is an easy fix that can be deployed along with any other coordinated HF.

[delta1]

#1301 Prevent high S signatures (and possibly other malleability causes) by consensus