Re: Open Timestamps

from my general understanding about blockchain,
we can not guarantee the time of blockchain itself at milliseconds level.
but with wider time window, it also can be part of timestamp.

I think this issue belong to the answer of "what is timestamp?"

regards
mountie

2016년 9월 26일 (월) 오후 11:25, Wayne Vaughan <wayne@tierion.com>님이 작성:

> 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
> ----------
>
> [image: Tierion] <http://tierion.com/>
>
> Wayne Vaughan / CEO wayne@tierion.com / 860.836.8633
>
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>
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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
>>>
>>
>>
>