BIP 119: Add another benefit for commiting to an input's index #996

pull benthecarman wants to merge 2 commits into bitcoin:master from benthecarman:bip119-sig-hash-single changing 1 files +7 −0

benthecarman commented at 8:06 AM on September 17, 2020: contributor

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BIP 119: Add another benefit for commiting to an input's index 32c4d533f9
benthecarman commented at 8:06 AM on September 17, 2020: contributor

cc @JeremyRubin
JeremyRubin commented at 8:20 PM on September 17, 2020: contributor

Can you add another sentence clarifying what "to be planned around <code>SIGHASH_SINGLE</code>" means?

You can add a sentence like: "were the input index not to be committed, X would happen, which would be undesirable because of Y"
Add extra sentence 33e34b5612
JeremyRubin commented at 3:34 AM on September 18, 2020: contributor

Based on what you describe I don't see it as an exploitable issue.

E.g., imagine an output <H> CTV <K> CHECKSIG. Assuming H does not commit to index, and K does sighash single, then the signature is only valid if it is at the correct index, right? So having it redundantly with CTV doesn't matter.

Can you make an example where concretely a bad outcome happens? It may just be me, but I'm not seeing it.
benthecarman closed this on Sep 29, 2020
benthecarman commented at 10:17 AM on September 29, 2020: contributor

@JeremyRubin you're right

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