<html><head><meta http-equiv="Content-Type" content="text/html charset=us-ascii"></head><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space;">Thanks Tony,<div><br><div>On Aug 22, 2014, at 4:46 PM, Tony Arcieri <<a href="mailto:bascule@gmail.com">bascule@gmail.com</a>> wrote:<br><div><br class="Apple-interchange-newline"><blockquote type="cite"><div dir="ltr"><div class="gmail_extra"><div class="gmail_quote">On Fri, Aug 22, 2014 at 3:33 PM, Tao Effect <span dir="ltr"><<a href="mailto:contact@taoeffect.com" target="_blank">contact@taoeffect.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin: 0px 0px 0px 0.8ex; border-left-width: 1px; border-left-color: rgb(204, 204, 204); border-left-style: solid; padding-left: 1ex; position: static; z-index: auto;"><div style="word-wrap:break-word"><div class="">Speaking of unsupported assertions, that "the merits of proof-of-work [are] debatable" needs to be substantiated with something, especially if you are comparing it to pre-PoW concepts.</div>
</div></blockquote><div><br></div><div>Systems that use a Bitcoin-like proof-of-work function are both:</div><div><br></div><div>1) Monumentally inefficient</div></div></div></div></blockquote><div><br></div><div>I'm guessing you are referring to either having to wait for transactions to confirm, and/or "wasted CPU". I addressed the latter in previous email with a reference to Vitalik's discussion of PoW algos that serve to better society (think folding @ home, SETI, etc.).</div><div><br></div><div>Re the former (txn delay), yes that's an issue with PoW consensus algos, and why some look to others.</div><br><blockquote type="cite"><div dir="ltr"><div class="gmail_extra"><div class="gmail_quote"><div>2) Vulnerable to an attacker who wins the proof-of-work lottery most of the time, like has <a href="http://www.coindesk.com/ghash-io-never-launch-51-attack/">recently happened to Bitcoin</a></div>
</div></div></div></blockquote><div dir="ltr"><div class="gmail_extra"><div><br></div></div></div><div>Yes, this is a very interesting problem that many are working on. Solution to pooled mining is known:</div><div><br></div><div><a href="http://hackingdistributed.com/2014/06/18/how-to-disincentivize-large-bitcoin-mining-pools/">http://hackingdistributed.com/2014/06/18/how-to-disincentivize-large-bitcoin-mining-pools/</a></div><div><br></div><div>There are many others who are suggesting interesting ways of combatting 51% issues:</div><div><br></div><div>- <a href="https://blog.ethereum.org/2014/07/05/stake/">https://blog.ethereum.org/2014/07/05/stake/</a></div><div>- <a href="https://bitcointalk.org/index.php?topic=309073.msg7385002#msg7385002">https://bitcointalk.org/index.php?topic=309073.msg7385002#msg7385002</a></div><div>- <a href="https://eprint.iacr.org/2014/452.pdf">https://eprint.iacr.org/2014/452.pdf</a></div><div><br></div><br><blockquote type="cite"><div dir="ltr"><div class="gmail_extra"><div>Compounding this problem is the desire to prevent key compromise in Bitcoin-like systems via the use of multisignature trust and trusted third parties which sign-off on certain operations. This approach centralizes authority, in which case a consensus-based system like Ripple with trusted gateways could be used instead. If it were, it'd be much more efficient, and arguably have better security properties.</div>
</div></div></blockquote><br></div><div>I'd rather chance DPOS to address efficiency concerns [1] than rely on "trusted gateways", that reminds me too much of the CAs we're trying to get away from.</div><div><br></div><div>[1] <a href="http://wiki.bitshares.org/index.php/DPOS">http://wiki.bitshares.org/index.php/DPOS</a></div><div><br></div><div>Thanks for bringing up the 51% issue btw, this is something that I need to do more reading on. At the moment I'm just collecting links... :P</div><div><br></div><div>Kind regards,</div><div>Greg</div><div><br></div><div><div><span style="orphans: 2; widows: 2;">--</span><br style="orphans: 2; widows: 2;"><span style="orphans: 2; widows: 2;">Please do not email me anything that you are not comfortable also sharing</span><span style="orphans: 2; widows: 2;"> with the NSA.</span></div><div><span style="orphans: 2; widows: 2;"><br></span></div></div><br></div></div></body></html>