Return-Path: Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id B67FF25A for ; Thu, 16 Aug 2018 02:22:35 +0000 (UTC) X-Greylist: whitelisted by SQLgrey-1.7.6 Received: from mail-wm0-f51.google.com (mail-wm0-f51.google.com [74.125.82.51]) by smtp1.linuxfoundation.org (Postfix) with ESMTPS id F02441A0 for ; Thu, 16 Aug 2018 02:22:34 +0000 (UTC) Received: by mail-wm0-f51.google.com with SMTP id l2-v6so14353967wme.1 for ; Wed, 15 Aug 2018 19:22:34 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:reply-to:from:date:message-id :subject:to:cc; bh=REvIgGrXTXMzVh/nd0otRAPoe5FdW4u2harYESsM300=; b=h2d6FCRfh3YgQ8f2vHy7KYbMvXKSq5/8Z84oeX5m1DzQou8NGMi3udIRrmz+l1ZyWJ MmMmCzLsI1yGPQz2lEVQQDNgJElKw2tLog9QQY6ZlX0uA+ZwQ6q50QS/IFrpVjjABpJA MgqoRrEsUXT2qdYY3xKM+sPVrYbpumX3UnR9y9GEmZtwTJ+fH4iJZamNaw8FMdUSHn2t VFc6YTzCjpUySRBY3gWjl9DTEgrPe5QWWjZJ1suMzzyyQduEq/PvvyWh1Sm4Lu/4XsOr Nqo1Co50Kk9Ll8AjVb8yVx3eFaRB1d2pMC3aOvBJtiDPgBW5c+vGQ8h1glCP0oAvsXaI MwsA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:reply-to :from:date:message-id:subject:to:cc; bh=REvIgGrXTXMzVh/nd0otRAPoe5FdW4u2harYESsM300=; b=hRxrrBCg+ko5lb9BLvBtqCZFTgFdc3kFkziQRL0LQ3hRglAt4hzyVWW3C9Q2fwcCGD 9/C3MXKKlrAei9VLNKDEBqv7PPvZls8KO+Gj2ezDy4As+/N0gKhXCMPCNB7/dyO9I5mf T/P4OPbKJ/1a7ysZSLmvvvVzUILATIQ3UTP5pmE2He5oqyNdexOLM47szsCK8y3HDzDo 6hS2zpIggEgsc1OgtUQlflLJtsd2Sso1cgAl9+XFpxzo1fRhCEzJNWRINxc5901yELFs idO62W1bBmCa1uVlkM1FSWyWNGpHILz61XOZPvsE+0TV1AQcBKcEN4+ZlrHhC/0td/dh 9nYw== X-Gm-Message-State: AOUpUlFHPBtt91sg5icjp5MLEg8gH6cwoG8q2HXwpw85mLNQajedeb2a dM2Lus7zk4EnA9/xNOXV9y+sqgXb8s7urSlidEoV1g== X-Google-Smtp-Source: AA+uWPzEyzWHgwt6IlYNS+peSiR3A02qiSoEIzzGIlBo4q3/MDbkrV4NvgPfGjWiGDNeX4TVBoLtNcZxd44az2fToPI= X-Received: by 2002:a1c:1805:: with SMTP id 5-v6mr14075001wmy.25.1534386153376; Wed, 15 Aug 2018 19:22:33 -0700 (PDT) MIME-Version: 1.0 References: <201808160106.54960.luke@dashjr.org> In-Reply-To: <201808160106.54960.luke@dashjr.org> Reply-To: lautaro.dragan@gmail.com From: Lautaro Dragan Date: Wed, 15 Aug 2018 23:22:21 -0300 Message-ID: To: Luke Dashjr , Bitcoin Protocol Discussion Content-Type: multipart/alternative; boundary="0000000000009ed1560573841d75" X-Spam-Status: No, score=-1.0 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FROM,FREEMAIL_REPLYTO,HTML_MESSAGE, RCVD_IN_DNSWL_NONE autolearn=no version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on smtp1.linux-foundation.org X-Mailman-Approved-At: Thu, 16 Aug 2018 11:50:08 +0000 Subject: Re: [bitcoin-dev] Claiming an OP_RETURN Prefix X-BeenThere: bitcoin-dev@lists.linuxfoundation.org X-Mailman-Version: 2.1.12 Precedence: list List-Id: Bitcoin Protocol Discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 16 Aug 2018 02:22:35 -0000 --0000000000009ed1560573841d75 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Thanks Christopher. > op_return outputs can be pruned because they are not spendable. putting a hash on in the witness script data won't make things better (it would actually make them worse) and it definitely doesn't help "block size bloat". Agreed > I think I'm missing some context, but if you're using op_return purely for timestamping I would recommend using pay 2 contract instead. And > If you're *actually* just doing timestamping you're better off using OpenTimestamps. But many times people think they're just doing timestamping in reality mere timestamps are insufficient for the task. No, it's not only timestamping. Think of it as storing the URL of something in the OP_RETURN, only that instead of a URL it's a hash. But it's not just the hash of the work =E2=80=94 IPFS adds a few other elements that affect t= his hash, so calculating it out of the file being added won't do. Also, the batching OTS uses and the batching we use (using IPFS directories) are incompatible. > Can a miner identify which transactions came from your software simply by running a copy themselves? If so, then they can censor your transactions no matter how you encode them. Miners would have to try and `ipfs cat` every OP_RETURN of every transaction (maybe filtering by byte length), which is a relatively high cost operation. But such a script is straight forward to write and can be hosted in a cheap AWS machine. We're talking about less than a week of coding and less than a hundred bucks of hosting, so if they're out to get you it won't make a difference. > Choosing not to mine transactions is not censorship. Is it not, if for political rather than economical reasons? These transactions pay fees like any other. El mi=C3=A9., 15 de ago. de 2018 a la(s) 22:08, Luke Dashjr via bitcoin-dev= < bitcoin-dev@lists.linuxfoundation.org> escribi=C3=B3: > On Wednesday 15 August 2018 21:54:50 Christopher Allen via bitcoin-dev > wrote: > > On Wed, Aug 15, 2018 at 2:24 PM Jude Nelson via bitcoin-dev < > > bitcoin-dev@lists.linuxfoundation.org> wrote: > > > Can a miner identify which transactions came from your software simpl= y > by > > > running a copy themselves? If so, then they can censor your > transactions > > > no matter how you encode them. > > > > Possibly, but in the IPFS case I suspect the latency required to inspec= t > > all hashes would likely impact the ability of the miner to succeed in > the > > block. (True? I don=E2=80=99t touch mining software.) > > Not true at all. > > > Thus as long as all hashes look the same, and there are multiple conten= t > > addressable schemes that use hashes that have to be searched in order t= o > > know to censor, you have to censor all or none. > > Choosing not to mine transactions is not censorship. > > Luke > _______________________________________________ > bitcoin-dev mailing list > bitcoin-dev@lists.linuxfoundation.org > https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev > --0000000000009ed1560573841d75 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
Thanks Christopher.=C2=A0

>=C2=A0op_return outputs can be pruned because th= ey are not spendable.
putti= ng a hash on in the witness script data won't make things better=
(it w= ould actually make them worse) and it definitely doesn't help"bl= ock size bloat".

Agreed

=
>=C2=A0I think I'm missing some context, but i= f you're using op_return purely
= for timestamping I would recommend using pay 2 contract=C2=A0 instead.

And

> If you're *actually*= just doing timestamping you're better off using OpenTimestamps. But ma= ny times people think they're just doing timestamping in reality mere t= imestamps are insufficient for the task.

No, it's not only timestamping. Think= of it as storing the URL of something in the OP_RETURN, only that instead = of a URL it's a hash. But it's not just the hash of the work =E2=80= =94 IPFS adds a few other elements that affect this hash, so calculating it= out of the file being added won't do. Also, the batching OTS uses and = the batching we use (using IPFS directories) are incompatible.

> Can a miner id= entify which transactions came from your software simply by running a copy = themselves?=C2=A0 If so, then they can censor your transactions no matter h= ow you encode them.

Miners would h= ave to try and `ipfs cat` every OP_RETURN of every transaction (maybe filte= ring by byte length), which is a relatively high cost operation. But such a= script is straight forward to write and can be hosted in a cheap AWS machi= ne. We're talking about less than a week of coding and less than a hund= red bucks of hosting, so if they're out to get you it won't make a = difference.

> Choosing not to mine transactions is not censorship.

Is it not, if for political rather than econom= ical reasons? These transactions pay fees like any other.



El mi=C3=A9., 15 de ago. de 2018 a la(s) 22:08, L= uke Dashjr via bitcoin-dev <bitcoin-dev@lists.linuxfoundation.org> escribi=C3=B3:
On Wednesday 15 August 2018 21:54:50= Christopher Allen via bitcoin-dev wrote:
> On Wed, Aug 15, 2018 at 2:24 PM Jude Nelson via bitcoin-dev <
> bitcoin-dev@lists.linuxfoundation.org> wrote:
> > Can a miner identify which transactions came from your software s= imply by
> > running a copy themselves?=C2=A0 If so, then they can censor your= transactions
> > no matter how you encode them.
>
> Possibly, but in the IPFS case I suspect the latency required to inspe= ct
> all hashes would likely=C2=A0 impact the ability of the miner to succe= ed in the
> block. (True? I don=E2=80=99t touch mining software.)

Not true at all.

> Thus as long as all hashes look the same, and there are multiple conte= nt
> addressable schemes that use hashes that have to be searched in order = to
> know to censor, you have to censor all or none.

Choosing not to mine transactions is not censorship.

Luke
_______________________________________________
bitcoin-dev mailing list
= bitcoin-dev@lists.linuxfoundation.org
https://lists.linuxfoundation.org/mail= man/listinfo/bitcoin-dev
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