<div dir="ltr"><div class="gmail_extra"><div class="gmail_quote">On Tue, Jul 26, 2016 at 9:58 PM, Martijn Meijering via bitcoin-dev <span dir="ltr"><<a href="mailto:bitcoin-dev@lists.linuxfoundation.org" target="_blank">bitcoin-dev@lists.linuxfoundation.org</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
Is there a reason miners would be more likely to engage in selfish<br>
mining of sync flags than they are now with ordinary blocks?<br>
</blockquote><div><br><br></div><div>This proposal has the same effect as adding mandatory empty blocks.<br><br></div><div>POW targeted at 2 minutes means that the POW for the flag is 25% of the block POW. That gives a flag every 2 minutes and a block every 8 minutes.<br><br>It has the feature that the conversion rate from hashing power to reward is the same for the flags and the blocks. A flag get 25% of the reward for 25% of the effort.<br></div><div><br></div><div>A soft fork to add this rule would have a disadvantage relative to a competing chain. It would divert 20% of its hashing power to the flag blocks, which would be ignored by legacy nodes. The soft fork would need 55% of the hashing power to win the race.<br><br></div><div>This isn't that big a deal if a 75% activation threshold is used. It might be worth bumping it up to 80% in that case.<br><br></div><div>This rule would mean that headers first clients would have to download more information to verify the longest chain. If they only download the headers, they are missing 20% of the POW.<br></div></div></div></div>