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From: Matthew Mitchell <matthewmitchell@godofgod.co.uk>
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Date: Thu, 13 Sep 2012 16:46:21 +0100
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Subject: Re: [Bitcoin-development] Segmented Block Relaying BIP draft.
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On 13 Sep 2012, at 16:16, Gregory Maxwell <gmaxwell@gmail.com> wrote:

> Sorry, I'm still not seeing what the value is.  How is the tree level
> useful to anyone?  If you did want to get only parts of the
> transaction list, why not just ranges from the lowest level?

Obtaining a particular tree level allows you to verify segments without =
needing to download all the transaction hashes first. You only need one =
hash per segment. For instance if you want to divide the block into 8 =
segments you specify level 3 and download 8 hashes. You could download =
all transaction hashes if you wanted and it would still work, it just =
requires more data transfer for the hashes. This was the reason why =
merkle trees were used in bitcoin, to avoid requiring all hashes to =
verify data.