Mark, thank you for a very clear explanation of why this proposal would be dangerous.

What I have noted in many discussions regarding blockchain security and proof-or-work schemes, is there is a wide gulf between those few people who can clearly reason about it, and those who have a lot trouble with it (I mostly fall into the later camp).

I wonder if anyone can point to resources who can help "the rest of us" reason clearly about these types of proposals, prior to bringing them to this list or a senior dev.  

Ideally it would illustrate various past proposals, explain why they would and wouldnt work, and build up some fundamental concepts, like a "Newtons laws of blockchain security" that would help us evaluate such ideas on our own.

Blockchain stuff is often counterintuitive.



On Sun, Dec 22, 2013 at 7:22 PM, Mark Friedenbach <mark@monetize.io> wrote:
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1

Ryan, these sort of adjustments introduce security risks. If you were
isolated from the main chain by a low-hashpower attacker, how would
you know? They'd need just three days without you noticing that
network block generation has stalled - maybe they wait for a long
weekend - then after that the block rate is normal but completely
controlled by the attacker (and isolated from mainnet).

There are fast acting alternative difficulty adjustment algorithms
being explored by some alts, such as the 9-block interval, 144-block
window, Parks-McClellan FIR filter used by Freicoin to recover from
just such a mining bubble. If it were to happen to bitcoin, there
would be sophisticated alternative to turn to, and enough time to make
the change.

On 12/22/2013 07:10 PM, Ryan Carboni wrote:
> I think Bitcoin should have a sanity check: after three days if
> only four blocks have been mined, difficulty should be adjusted
> downwards.
>
> This might become important in the near future. I project a
> Bitcoin mining bubble.
>
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.14 (GNU/Linux)
Comment: GPGTools - http://gpgtools.org
Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/
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=5Q2H
-----END PGP SIGNATURE-----

------------------------------------------------------------------------------
Rapidly troubleshoot problems before they affect your business. Most IT
organizations don't have a clear picture of how application performance
affects their revenue. With AppDynamics, you get 100% visibility into your
Java,.NET, & PHP application. Start your 15-day FREE TRIAL of AppDynamics Pro!
http://pubads.g.doubleclick.net/gampad/clk?id=84349831&iu=/4140/ostg.clktrk
_______________________________________________
Bitcoin-development mailing list
Bitcoin-development@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/bitcoin-development



--
Robin R Chauhan
CEO, Pathway Intelligence Inc
robin@pathwayi.com
Office: 778-588-6217 Ext. 201
Cell: 604-865-0517
Fax: 778-588-1042
http://pathwayi.com/
---------------------------------------------------------------------
This transmission (including any attachments) may contain confidential
information or constitute non-public information. Any use of this
information by anyone other than the intended recipient is prohibited.
If you have received this transmission in error, please immediately
reply to the sender and delete this information from your system. 
Use, dissemination, distribution, or reproduction of this transmission 
by unintended recipients is not authorized and may be unlawful.