From: Tamas Blummer <tamas.blummer@gmail.com>
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Date: Thu, 23 May 2019 21:10:53 +0200
In-Reply-To: <CABm2gDoFS=dNbqzEo+RcWb32Kx4QM7YHLxYLOG54a=RGR8rQcw@mail.gmail.com>
To: =?utf-8?Q?Jorge_Tim=C3=B3n?= <jtimon@jtimon.cc>
References: <CAD5xwhgHyR5qdd09ikvA_vgepj4o+Aqb0JA_T6FuqX56ZNe1RQ@mail.gmail.com>
	<42F53D61-BAAE-464F-BB0D-4D0CDC554D9A@gmail.com>
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Cc: Bitcoin Protocol Discussion <bitcoin-dev@lists.linuxfoundation.org>
Subject: Re: [bitcoin-dev] OP_DIFFICULTY to enable difficulty hedges (bets)
 without an oracle and 3rd party.
Precedence: list


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The parameter used is property of the block just like the block height =
is a property and is already evaluated in scripts,
so no new kind of dependency or encapsulation break.

The transaction itself was not invalid in a re-org but evtl. others =
spending it if the difficulty on that fork is different,
this is however intended as then on that fork the other was the winner.

Tamas Blummer

> On May 23, 2019, at 21:03, Jorge Tim=C3=B3n <jtimon@jtimon.cc> wrote:
>=20
> The complains I could imagine about this, (apart from being a very
> specific use case) are the same complains I heard about op_expiry.
> Namely, that in a reorg, the same tx, having been valid in a given
> block could potentially become invalid in some other block mining it.
> I guess in this case the situation is less likely in this case than
> with op_expiry, but it is still possible.
> Another complain I could imagine is this kind of forces the
> implementation to break some existing encapsulations, but I guess
> those are just implementation details not that relevant here.
> I personally don't have strong feelings towards this proposal one way
> or the other, I'm just imagining what other people may complain about.
>=20
> On Thu, May 23, 2019 at 8:33 PM Tamas Blummer via bitcoin-dev
> <bitcoin-dev@lists.linuxfoundation.org> wrote:
>>=20
>> Difficulty change has profound impact on miner=E2=80=99s production =
thereby introduce the biggest risk while considering an investment.
>> Commodity markets offer futures and options to hedge risks on =
traditional trading venues. Some might soon list difficulty futures.
>>=20
>> I think we could do much better than them natively within Bitcoin.
>>=20
>> A better solution could be a transaction that uses nLocktime =
denominated in block height, such that it is valid after the difficulty =
adjusted block in the future.
>> A new OP_DIFFICULTY opcode would put onto stack the value of =
difficulty for the block the transaction is included into.
>> The output script may then decide comparing that value with a strike =
which key can spend it.
>> The input of the transaction would be a multi-sig escrow of those who =
entered the bet.
>> The winner would broadcast.
>>=20
>> Once signed by both the transaction would not carry any counterparty =
risk and would not need an oracle to settle according to the bet.
>>=20
>> I plan to draft a BIP for this as I think this opcode would serve =
significant economic interest of Bitcoin economy, and is compatible with =
Bitcoin=E2=80=99s aim not to introduce 3rd party to do so.
>>=20
>> Do you see a fault in this proposal or want to contribute?
>>=20
>> Tamas Blummer
>>=20
>> _______________________________________________
>> bitcoin-dev mailing list
>> bitcoin-dev@lists.linuxfoundation.org
>> https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev


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