[bitcoin-dev] Blockchain verification flag (BIP draft)

[Rusty Russell]

Gavin Andresen via bitcoin-dev <bitcoin-dev at lists.linuxfoundation.org>
writes:
> Overall, good idea.
>
> Is there a write-up somewhere describing in detail the 'accidental selfish
> mining' problem that this mitigates? I think a link in the BIP to a fuller
> description of the problem and how validation-skipping makes it go away
> would be helpful.
>
> RE: which bit to use:  the draft versionbits BIP and BIP101 use bit 30; to
> avoid confusion, I think it would be better to use bit 0.

Yes, BIP9 need to be adjusted (setting bit 30 means BIP9 counts it as a
vote against all softforks).  BIP101 uses bits 0,1,2 AFAICT, so perhaps
start from the other end and use bit 29?  We can bikeshed that later
though...

> I agree with Jannes Faber, behavior with respect to SPV clients should be
> to only tell them about fully validated headers.

A delicate balance.  If we penalize these blocks too much, it's
disincentive to set the bit.  Fortunately it's easy for SPV clients to
decide for themselves, I think?

Cheers,
Rusty.