From: Bram Cohen <bram@bittorrent•com>
Cc: Bitcoin Protocol Discussion <bitcoin-dev@lists•linuxfoundation.org>
Subject: Re: [bitcoin-dev] Height based vs block time based thresholds
Date: Tue, 4 Jul 2017 20:39:09 -0700 [thread overview]
Message-ID: <CA+KqGkqMtHzxzKObn7OkXsdrP4sKOFm-z1bJWThhPe4jXFmzDw@mail.gmail.com> (raw)
In-Reply-To: <KXL-Ie0q1dKTlbQ2XCyTRCzoQLND-Q7M9CFvYTfhjgeiZ4K3knpetQSwwLviO6whuHXQnFPg-rg8q1xW8w5mNnYFxalvx5_9Vci63lC9ju4=@protonmail.ch>
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On Tue, Jul 4, 2017 at 6:30 PM, shaolinfry via bitcoin-dev <
bitcoin-dev@lists•linuxfoundation.org> wrote:
> Some people have criticized BIP9's blocktime based thresholds arguing they
> are confusing (the first retarget after threshold). It is also vulnerable
> to miners fiddling with timestamps in a way that could prevent or delay
> activation - for example by only advancing the block timestamp by 1 second
> you would never meet the threshold (although this would come a the penalty
> of hiking the difficulty dramatically).
>
> On the other hand, the exact date of a height based thresholds is hard to
> predict a long time in advance due to difficulty fluctuations. However,
> there is certainty at a given block height and it's easy to monitor.
>
You could get most of the best of both with a combination of the two: Have
the activation be a timestamp plus a certain number of blocks to come after
maybe about 100, which is more than enough to make sure all the games which
can be played with timestamps have passed but a small enough amount that it
doesn't add much uncertainty to wall clock time.
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next prev parent reply other threads:[~2017-07-05 3:39 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-07-05 1:30 shaolinfry
2017-07-05 2:25 ` Troy Benjegerdes
2017-07-05 3:39 ` Bram Cohen [this message]
2017-07-05 3:50 ` Luke Dashjr
2017-07-05 4:00 ` shaolinfry
2017-07-05 4:10 ` Luke Dashjr
2017-07-05 19:44 ` Hampus Sjöberg
2017-07-06 17:20 ` Jorge Timón
2017-07-06 17:41 ` Eric Voskuil
2017-07-05 8:06 ` Gregory Maxwell
2017-07-05 8:54 ` Kekcoin
2017-07-06 20:43 ` Luke Dashjr
2017-07-07 5:52 ` shaolinfry
2017-07-07 9:51 ` Jorge Timón
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