Date: Wed, 2 Mar 2016 13:20:28 -0500
From: Peter Todd <pete@petertodd.org>
To: Luke Dashjr <luke@dashjr.org>
Message-ID: <20160302182028.GA7783@savin.petertodd.org>
References: <201603021456.15820.luke@dashjr.org>
MIME-Version: 1.0
Content-Type: multipart/signed; micalg=pgp-sha256;
	protocol="application/pgp-signature"; boundary="+QahgC5+KEYLbs62"
Content-Disposition: inline
In-Reply-To: <201603021456.15820.luke@dashjr.org>
Cc: bitcoin-dev@lists.linuxfoundation.org
Subject: Re: [bitcoin-dev] Hardfork to fix difficulty drop algorithm
Precedence: list


--+QahgC5+KEYLbs62
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
Content-Transfer-Encoding: quoted-printable

On Wed, Mar 02, 2016 at 02:56:14PM +0000, Luke Dashjr via bitcoin-dev wrote:
> To alleviate this risk, it seems reasonable to propose a hardfork to the=
=20
> difficulty adjustment algorithm so it can adapt quicker to such a signifi=
cant=20
> drop in mining rate. BtcDrak tells me he has well-tested code for this in=
 his=20
> altcoin, which has seen some roller-coaster hashrates, so it may even be=
=20
> possible to have such a proposal ready in time to be deployed alongside S=
egWit=20
> to take effect in time for the upcoming subsidy halving. If this slips, I=
=20
> think it may be reasonable to push for at least code-readiness before Jul=
y,=20
> and possibly roll it into any other hardfork proposed before or around th=
at=20
> time.
>=20
> I am unaware of any reason this would be controversial, so if anyone has =
a=20
> problem with such a change, please speak up sooner rather than later. Oth=
er=20
> ideas or concerns are of course welcome as well.

Changing the difficulty adjustment algorithm significantly changes the
security of the whole system, as it lets attackers create fake chains
with a lot less hashing power.

Given as tx fees rise this problem will hopefully be a one-time issue, a
simple fixed difficulty adjustment probably makes sense. No need to
bring in new algorithms here with controversial new security tradeoffs.

--=20
https://petertodd.org 'peter'[:-1]@petertodd.org
0000000000000000045a03e0e551c4e674f301e0a8eeb217a31ad13580446626

--+QahgC5+KEYLbs62
Content-Type: application/pgp-signature; name="signature.asc"
Content-Description: Digital signature

-----BEGIN PGP SIGNATURE-----
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==
=3CWU
-----END PGP SIGNATURE-----

--+QahgC5+KEYLbs62--