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| author | Luke Dashjr <luke@dashjr.org> | 2021-03-15 21:48:15 +0000 |
|---|---|---|
| committer | bitcoindev <bitcoindev@gnusha.org> | 2021-03-15 21:48:30 +0000 |
| commit | 1c03c4d24bf3fe5e50f604be6f302e33e3010ca5 (patch) | |
| tree | fa10bf29272c528596e5ac6b01d8dddcfd597b54 | |
| parent | 29df3884a2581f99de6374bb01d7f049df3eeb4c (diff) | |
| download | pi-bitcoindev-1c03c4d24bf3fe5e50f604be6f302e33e3010ca5.tar.gz pi-bitcoindev-1c03c4d24bf3fe5e50f604be6f302e33e3010ca5.zip | |
[bitcoin-dev] PSA: Taproot loss of quantum protections
| -rw-r--r-- | 6d/aaa614c75f97fc8ab048fc119188897982b347 | 119 |
1 files changed, 119 insertions, 0 deletions
diff --git a/6d/aaa614c75f97fc8ab048fc119188897982b347 b/6d/aaa614c75f97fc8ab048fc119188897982b347 new file mode 100644 index 000000000..2ef88c124 --- /dev/null +++ b/6d/aaa614c75f97fc8ab048fc119188897982b347 @@ -0,0 +1,119 @@ +Return-Path: <luke@dashjr.org> +Received: from smtp2.osuosl.org (smtp2.osuosl.org [140.211.166.133]) + by lists.linuxfoundation.org (Postfix) with ESMTP id 9C28EC0001 + for <bitcoin-dev@lists.linuxfoundation.org>; + Mon, 15 Mar 2021 21:48:30 +0000 (UTC) +Received: from localhost (localhost [127.0.0.1]) + by smtp2.osuosl.org (Postfix) with ESMTP id 895AB43144 + for <bitcoin-dev@lists.linuxfoundation.org>; + Mon, 15 Mar 2021 21:48:30 +0000 (UTC) +X-Virus-Scanned: amavisd-new at osuosl.org +X-Spam-Flag: NO +X-Spam-Score: -0.202 +X-Spam-Level: +X-Spam-Status: No, score=-0.202 tagged_above=-999 required=5 + tests=[BAYES_40=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, + DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, + SPF_PASS=-0.001] autolearn=ham autolearn_force=no +Authentication-Results: smtp2.osuosl.org (amavisd-new); + dkim=pass (1024-bit key) header.d=dashjr.org +Received: from smtp2.osuosl.org ([127.0.0.1]) + by localhost (smtp2.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) + with ESMTP id j7ry9kdkY4U5 + for <bitcoin-dev@lists.linuxfoundation.org>; + Mon, 15 Mar 2021 21:48:29 +0000 (UTC) +X-Greylist: from auto-whitelisted by SQLgrey-1.8.0 +Received: from zinan.dashjr.org (zinan.dashjr.org [192.3.11.21]) + by smtp2.osuosl.org (Postfix) with ESMTP id 4E3DC4000B + for <bitcoin-dev@lists.linuxfoundation.org>; + Mon, 15 Mar 2021 21:48:29 +0000 (UTC) +Received: from ishibashi.lan (unknown [12.190.236.209]) + (Authenticated sender: luke-jr) + by zinan.dashjr.org (Postfix) with ESMTPSA id 6965238A009E + for <bitcoin-dev@lists.linuxfoundation.org>; + Mon, 15 Mar 2021 21:48:16 +0000 (UTC) +DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=dashjr.org; s=zinan; + t=1615844908; bh=YerwjjIZG6WUFg8EYDHdazr9qu9MyXzzihWQyozSz3E=; + h=From:To:Subject:Date; + b=LwaxAJMXX0WfHLZ+Pk+n1/n70BH/1DIiPjySjvf6y5+cuWrptmVE1NruwKZmaLhy5 + DTBrVoR8YeGNEEPylRBr74hcQ+gG70gxSbXtBvoXnMSOKF3E1iqMlbbVDolJPdnpWY + 0hAkE4mh7BOd5fpq54JPHMbClFzsJEpQbJGyAAfQ= +X-Hashcash: 1:25:210315:bitcoin-dev@lists.linuxfoundation.org::=hqcgzBkQV2Nt/++:a5EzX +From: Luke Dashjr <luke@dashjr.org> +To: Bitcoin Protocol Discussion <bitcoin-dev@lists.linuxfoundation.org> +Date: Mon, 15 Mar 2021 21:48:15 +0000 +User-Agent: KMail/1.9.10 +MIME-Version: 1.0 +Content-Type: text/plain; + charset="us-ascii" +Content-Transfer-Encoding: 7bit +Content-Disposition: inline +Message-Id: <202103152148.15477.luke@dashjr.org> +Subject: [bitcoin-dev] PSA: Taproot loss of quantum protections +X-BeenThere: bitcoin-dev@lists.linuxfoundation.org +X-Mailman-Version: 2.1.15 +Precedence: list +List-Id: Bitcoin Protocol Discussion <bitcoin-dev.lists.linuxfoundation.org> +List-Unsubscribe: <https://lists.linuxfoundation.org/mailman/options/bitcoin-dev>, + <mailto:bitcoin-dev-request@lists.linuxfoundation.org?subject=unsubscribe> +List-Archive: <http://lists.linuxfoundation.org/pipermail/bitcoin-dev/> +List-Post: <mailto:bitcoin-dev@lists.linuxfoundation.org> +List-Help: <mailto:bitcoin-dev-request@lists.linuxfoundation.org?subject=help> +List-Subscribe: <https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev>, + <mailto:bitcoin-dev-request@lists.linuxfoundation.org?subject=subscribe> +X-List-Received-Date: Mon, 15 Mar 2021 21:48:30 -0000 + +I do not personally see this as a reason to NACK Taproot, but it has become +clear to me over the past week or so that many others are unaware of this +tradeoff, so I am sharing it here to ensure the wider community is aware of +it and can make their own judgements. + +Mark Friedenbach explains on his blog: + https://freicoin.substack.com/p/why-im-against-taproot + +In short, Taproot loses an important safety protection against quantum. +Note that in all circumstances, Bitcoin is endangered when QC becomes a +reality, but pre-Taproot, it is possible for the network to "pause" while a +full quantum-safe fix is developed, and then resume transacting. With Taproot +as-is, it could very well become an unrecoverable situation if QC go online +prior to having a full quantum-safe solution. + +Also, what I didn't know myself until today, is that we do not actually gain +anything from this: the features proposed to make use of the raw keys being +public prior to spending can be implemented with hashed keys as well. +It would use significantly more CPU time and bandwidth (between private +parties, not on-chain), but there should be no shortage of that for anyone +running a full node (indeed, CPU time is freed up by Taproot!); at worst, it +would create an incentive for more people to use their own full node, which +is a good thing! + +Despite this, I still don't think it's a reason to NACK Taproot: it should be +fairly trivial to add a hash on top in an additional softfork and fix this. + +In addition to the points made by Mark, I also want to add two more, in +response to Pieter's "you can't claim much security if 37% of the supply is +at risk" argument. This argument is based in part on the fact that many +people reuse Bitcoin invoice addresses. + +First, so long as we have hash-based addresses as a best practice, we can +continue to shrink the percentage of bitcoins affected through social efforts +discouraging address use. If the standard loses the hash, the situation +cannot be improved, and will indeed only get worse. + +Second, when/if quantum does compromise these coins, so long as they are +neglected or abandoned/lost coins (inherent in the current model), it can be +seen as equivalent to Bitcoin mining. At the end of the day, 37% of supply +minable by QCs is really no different than 37% minable by ASICs. (We've seen +far higher %s available for mining obviously.) + +To conclude, I recommend anyone using Bitcoin to read Mark's article, my +thoughts, and any other arguments on the topic; decide if this is a concern +to you, and make your own post(s) accordingly. Mark has conceded the argument +(AFAIK he doesn't have an interest in bitcoins anyway), and I do not consider +it a showstopper - so if anyone else out there does, please make yourself +known ASAP since Taproot has already moved on to the activation phase and it +is likely software will be released within the next month or two as things +stand. + +Luke + |