Subject: Re: [Bitcoin-development] Economics of information propagation

From: Tier Nolan <[email-masked]>
Date: Mon, 21 Apr 2014 12:34:49 +0100

On Mon, Apr 21, 2014 at 5:06 AM, Peter Todd <[email-masked]> wrote:

> Of course, in reality smaller miners can just mine on top of block headers
> and include no transactions and do no validation, but that is extremely
> harmful to the security of Bitcoin.
>

I don't think it reduces security much.  It is extremely unlikely that
someone would publish an invalid block, since they would waste their POW.

Presuming that new headers are correct is reasonable, as long as you check
the full block within a few minutes of receiving the header.

If anything, it increases security, since less hashing power is wasted
while the full block is broadcast.

Block propagation could take the form

- broadcast new header
- all miners switch to mining empty blocks
- broadcast new block
- miners update to a block with transactions

If the block doesn't arrive within a timeout, then the miner could switch
back to the old block.

This would mean that a few percent of empty blocks end up in the
blockchain, but that doesn't do any harm.

It is only harmful, if it is used as a DOS attack on the network.

The empty blocks will only occur when 2 blocks are found in quick
succession, so it doesn't have much affect on average time until 1
confirm.  Empty blocks are just as good for providing 1 of the 6 confirms
needed too.