W3C home > Mailing lists > Public > public-blockchain@w3.org > September 2016

Re: Open Timestamps

From: Wayne Vaughan <wayne@tierion.com>
Date: Thu, 29 Sep 2016 20:48:19 -0400
Message-ID: <CALwpO4dfOqi0D_htE1Y03F6vODrGrSh8-3-f21o2fVEb9-fTgQ@mail.gmail.com>
To: Peter Todd <pete@petertodd.org>
Cc: "S. Matthew English" <s.matthew.english@gmail.com>, Mountie Lee <mountie@paygate.net>, Melvin Carvalho <melvincarvalho@gmail.com>, Blockchain CG <public-blockchain@w3.org>
I'm with Peter.

With Chainpoint, we purposefully avoid using timestamping as part of our
vocabulary.  We consider Chainpoint a proof protocol. You are proving that
your data is cryptographically linked to a set of external sources.  If one
of those external sources provides a reliable source of time, then you can
use the proof as a timestamp. The key constraint to recognize is that you
inherit time from the anchor sources.

Version 1.0 of Chainpoint contained a non-authoritative timestamp field.
This field was removed in Chainpoint 2.0. The precision of time is
dependent on the anchor source. We are adding support for more anchor
types. In the future, we will include information about how time can be
derived from each anchor source.

I left some comments on strategies for achieving more precise time a few
days ago:


On Thu, Sep 29, 2016 at 8:35 PM, Peter Todd <pete@petertodd.org> wrote:

> On Mon, Sep 26, 2016 at 02:39:30PM +0200, S. Matthew English wrote:
> > here's an article I wrote recently about timestamping in bitcoin:
> >
> > https://cointelegraph.com/news/timestamp-hacking-debunking-the-myth-of-
> precision-timestamps
> I think your article both misunderstands and overstates the problem.
> Specifically:
> > You might have heard that one of the properties a Blockchain possesses
> is the
> > ability to “prove certain data exists at a certain moment of time” or
> that it
> > somehow “provides proof that some data existed at a specific time”. The
> > problem with these claims is that they are demonstrably false.
> Suppose I claim that as of Jan 1st, 2016, 12:01am - a specific time t - the
> following string existed:
>     "The Times 03/Jan/2009 Chancellor on brink of second bailout for banks"
> As my evidence, I provide Bitcoin block 0, and the hundreds of thousands of
> blocks that follow it.
> Is that claim false? I mean, maybe all the Bitcoin miners had their clocks
> wrong for seven consecutive years. Or maybe you're looking at a chain that
> someone made with tens of millions of dollars worth of electricity. But I
> can
> make those kinds of claims of *any* timestamping solution, so that's not
> terribly interesting.
> Sure, you can't naively say that a Bitcoin block header timestamp means
> that
> data existed as of the exact time in the block. But you have exceptionally
> high
> assurance that the header existed as of that date + a month, certainely as
> good
> if not better assurance than you can get by any traditional means like
> publishing notices in news papers.
> Saying otherwise - particularly saying that Chainpoint's claims are
> "demonstratable false" is fear-mongering; a more useful and accurate
> article
> would accurately explain the limitations of the tech and why it's
> non-trivial
> to prove things to within more than a day or so. Chainpoint may in fact be
> guilty of that false precision - I know my OpenTimestamps Client is, and I
> mention it in the "Known Issues" section of its README(1), with a link to
> further discussion on the topic - but let's not fall into the trap of
> making
> our debunking's themselves hype.
> 1) It's a tricky problem to fix, because just rounding off to the nearest
> day
> risks people getting confused by the interactions of timezone conversions
> across the international date line.
> --
> https://petertodd.org 'peter'[:-1]@petertodd.org
Received on Friday, 30 September 2016 00:48:54 UTC

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