[BitTorrent] Back to Merkle Hash Trees...

Olaf van der Spek OvdSpek at LIACS.NL
Sun Feb 6 17:08:24 EST 2005


Elliott Mitchell wrote:
>>From: Olaf van der Spek <OvdSpek at LIACS.NL>
>>Elliott Mitchell wrote:
>>
>>>>From: Olaf van der Spek <OvdSpek at LIACS.NL>
>>>>Elliott Mitchell wrote:
>>>
>>>Imagine you're handed a 16K block of data and a hash value. You're unsure
>>>whether this is internal nodes or a leaf (or even whether it is valid at
>>
>>How can you be unsure about that?
> 
> 
> Easily. Notably different protocol design than you're thinking. Crucially
> it never makes sense to transfer one hash at a time. If you transfer

Did I say I'd transfer only a single hash at a time?

> one hash at a time you've generated thousands of extra protocol messages.
> Given this you're likely to transfer blocks of hashes, at which point
> blocks of hashes will likely be of similar size to payload blocks.

But with a different block/field/message type.

> 
>>It should be clear from the protocol.
> 
> 
> Which is another reason I dislike THEX. The type is a protocol issue, not
> a standards issue. You might settle on markers similar THEX, at which
> point you've got to try both markers to distinguish the types.

Why can't you add both the markers and something else?

>>If not, an internal node is 21 or 41 bytes (IIRC), so your 16 kbyte 
>>block would not be an internal node.
> 
> 
> And a payload block can't be of this size? (notably the EOF)
> 
> You're still assuming transfer of one hash at a time, which is worthless

Am I?

> as you end up bloating the protocol overhead horrendously.


 
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