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From: Tim Ruffing <tim.ruffing@mmci.uni-saarland.de>
To: bitcoin-dev@lists.linuxfoundation.org
Subject: Re: [bitcoin-dev] Taproot: Privacy preserving switchable scripting
Date: Wed, 24 Jan 2018 16:38:11 +0100	[thread overview]
Message-ID: <1516808291.4277.25.camel@mmci.uni-saarland.de> (raw)
In-Reply-To: <CAAt2M1-oh=_Ro6+Srit0XYburK_abQgJiW0Jx=nmNyeToA2rSA@mail.gmail.com>

On Wed, 2018-01-24 at 13:51 +0100, Natanael via bitcoin-dev wrote:
> Sidenote: There's a risk here with interception, insertion of a new
> commitment and getting the new transaction into the blockchain first.
> However, I would suggest a mining policy here were two known
> conflicting transactions with commitments are resolved such that the
> one with the oldest commitment wins. How to address detection of
> conflicting transactions with commitments older than confirmed
> transactions isn't obvious. Some of these may be fully intentional by
> the original owner, such as a regretted transaction.

Okay, I think my proposal was wrong...

This looks better (feel free to break again):
1. Commit (H(classic_pk, tx), tx) to the blockchain, wait until confirmed
2. Reveal classic_pk in the blockchain

Then the tx in the first valid commitment wins. If the attacker
intercepts classic_pk, it won't help him. He cannot create the first
valid commitment, because it is created already. (The reason is that
the decommitment is canonical now; for all commitments, the
decommitment is just classic_pk.)

By the way, maybe I'm stating the obvious but Taproot (or similar) is
indeed very nice for outputs generated in the future: You can have a
path for a classical signature scheme and a path for a quantum-secure
scheme.

Best,
Tim


  reply	other threads:[~2018-01-24 15:38 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-01-23  0:30 [bitcoin-dev] Taproot: Privacy preserving switchable scripting Gregory Maxwell
2018-01-23  1:55 ` Chris Belcher
2018-01-23  2:51 ` Matt Corallo
2018-01-23 14:39   ` Mark Friedenbach
2018-01-23 21:23     ` Matt Corallo
2018-01-23 21:38       ` Gregory Maxwell
2018-01-23  6:44 ` Anthony Towns
2018-01-23 13:15   ` Gregory Maxwell
2018-01-23 22:22     ` Anthony Towns
2018-01-23 22:45       ` Gregory Maxwell
2018-01-24  1:52         ` Andrew Poelstra
2018-01-24  9:28           ` Tim Ruffing
2018-01-24 12:51         ` Natanael
2018-01-24 15:38           ` Tim Ruffing [this message]
2018-01-24 18:51             ` Natanael
2018-01-24 23:22               ` Tim Ruffing
2018-01-25  0:09                 ` Natanael
2018-01-26 13:14                   ` [bitcoin-dev] Recovery of old UTXOs in a post-quantum world Tim Ruffing
2018-01-27 17:07   ` [bitcoin-dev] Taproot: Privacy preserving switchable scripting Russell O'Connor
2018-01-27 17:23     ` Matt Corallo
2018-01-23 15:43 ` Greg Sanders
2018-01-26 21:34 ` Gregory Maxwell
2018-07-13  1:51   ` [bitcoin-dev] Generalised taproot Anthony Towns
2018-10-24  2:22     ` Pieter Wuille
2018-02-05  9:27 ` [bitcoin-dev] Taproot: Privacy preserving switchable scripting ZmnSCPxj

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