[Bitcoin-development] Bitcoin difficulty sanity check suggestion

Robin Ranjit Singh Chauhan robin at pathwayi.com
Mon Dec 23 20:22:49 UTC 2013

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

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

Blockchain stuff is often counterintuitive.

On Sun, Dec 22, 2013 at 7:22 PM, Mark Friedenbach <mark at monetize.io> wrote:

> 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.
> >
> 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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Robin R Chauhan
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