[Bitcoin-development] Cut-through propagation of blocks

[Alan Reiner]

On 05/24/2014 08:14 PM, Gregory Maxwell wrote:
> On Sat, May 24, 2014 at 5:04 PM, Alan Reiner <etotheipi at gmail.com> wrote:
>> I think the most important change is modifying the way Bitcoin Core
>> prioritizes blocks.  Right now it uses the first full block verified.
>> Instead, it should consider the first valid header received as highest
>> priority, but only mine on it once it has done full verification of the
> This directly opens an attack where as soon as you find a block you
> announce the header to the world and then you delay announcing the
> block content.  You can continue to mine on the block but no one else
> can (or alternatively they break their rule and risk extending an
> invalid block— bad news for SPV wallets)— then when you find a
> successor block or someone else finds a competing block you
> immediately announce the content.
>
> It basically means that you can always delay announcing a block and be
> sure that doing so doesn't deprive you of your winning position.
>
>

Would this not be solved by putting a expiration on application of this
logic?  For instance, if you haven't received the full new block within
5-10 seconds (perhaps adjusted based on local bandwidth), then the
header-received time is ignored.  Or is this too hacky?   I suppose this
is exactly what Ashley is trying to solve, she's just already made a few
more leaps forward in the design process than I have.  I'll stop
derailing it.