On Thu, Jan 23, 2014 at 01:56:54PM -0500, Peter Todd wrote:
> On Mon, Jan 20, 2014 at 10:07:31AM -0800, Thomas Hartman wrote:
> > https://bitcointalk.org/index.php?topic=146307.msg1553756#msg1553756
> >
> > n squared violates my intuition, can someone explain this? i would think n.
> >
> > it seems really important to me in terms of guessing the future of the
> > blockchain.
>
> It's really simple: You have n people using Bitcoin. Each of them does a
> single transaction per block, thus each block has n transactions. Thus
> each person needs to download ~n bytes worth of blockchain data and do
> ~n worth of computation to validate those transactions. Thus the system
> as a whole is doing n*n=n^2 work.

Oh, and a bit more detail: The basic design of Bitcoin *right now* is
such that to validate a transaction in a block you must have *all* prior
transactions. Similarly to create a block you must have *all* prior
transactions. Other possible blockchain designs have different
properties.

--
'peter'[:-1]@petertodd.org
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