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

Re: Open Timestamps

From: Wayne Vaughan <wayne@tierion.com>
Date: Mon, 26 Sep 2016 10:25:00 -0400
Message-ID: <CALwpO4dPAOVHj5D+C3bH4hHKZ_8+1mhG6UPzVcbLjDswR_T+pA@mail.gmail.com>
To: "S. Matthew English" <s.matthew.english@gmail.com>
Cc: Peter Todd <pete@petertodd.org>, Mountie Lee <mountie@paygate.net>, Melvin Carvalho <melvincarvalho@gmail.com>, Blockchain CG <public-blockchain@w3.org>, Jason Bukowski <jason@tierion.com>
Matthew,

You bring up a good point. Bitcoin is not a precise clock.

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.

A hash calendar <https://en.wikipedia.org/wiki/Hash_calendar> can get time
precision down to a few seconds.  The tradeoff is that you have to trust
the hash calendar until anchoring process completes and you generate your
final proof.  There are schemes to reduce the amount of trust required, but
they come at a cost.

You can also include a timestamp from a trusted source
<https://en.wikipedia.org/wiki/Trusted_timestamping> in your target hash.
It's highly unlikely that bitcoin miners and the administrator of your
trusted timestamp server would be able to collude to modify the timestamp
and the blockchain.

As Peter previously pointed out, an anchor into Bitcoin isn't 99.9999%
guaranteed until several confirmations.

By anchoring into multiple sources using multiple methods, you reduce the
risk that any single source will be compromised.  You can also cross check
anchor sources.  This was a key change to Chainpoint 2.0.  It comes at a
cost.  Multiple anchor sources complicates the verification process.
That's why we made them optional.

Wayne
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On Mon, Sep 26, 2016 at 8:39 AM, S. Matthew English <
s.matthew.english@gmail.com> wrote:

> here's an article I wrote recently about timestamping in bitcoin:
>
> https://cointelegraph.com/news/timestamp-hacking-debunking-the-myth-of-
> precision-timestamps
>
>
>
> On Fri, Sep 23, 2016 at 8:17 PM, Peter Todd <pete@petertodd.org> wrote:
>
>> On Fri, Sep 23, 2016 at 08:51:52AM +0000, Mountie Lee wrote:
>> > if you put the topic of yours to github issue (
>> > https://github.com/w3c/blockchain/issues)
>> > then peoples will be able to identify discussion status more easily and
>> > easy to participate.
>>
>> Oh, add it similar to this topic?
>>
>> https://github.com/w3c/blockchain/issues/14
>>
>> --
>> https://petertodd.org 'peter'[:-1]@petertodd.org
>>
>
>
Received on Monday, 26 September 2016 14:25:31 UTC

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