Re: [Mldonkey-users] Possible Idea for simultaineous inter-network transfers

[vnc]

Hi,

> Say we are downloading a file from client A on ed2k,
> which has ed2k md4_hash AAAA, and we notice that the
> same IP has a gnutella2 client/plugin running on it,
> (because it's mldonkey, sharaza etc) with the same
> file shared (same by filesize anyway..) with gnutella2
> "hash" BB:BB. Can we safely assume that if the client
> is mldonkey or sharaza, these two sources are the same
> file?
 
this has already been thought of, sure :).
There exist two possible solutions to that problem: A decentralised approach 
which you mentioned and a central database (not a very good idea IMHO). 

The problem we have is that we have to put a big amount of trust in the peer 
from which we get the associated hashes. If a file has been spread already we 
could broadcast a request to send us associated hashes. We then count how many 
different hashes we receive, the one which comes in most often is possibly the 
correct one. After successfully having downloaded the file, we put the 
hash-association in our database for further information. Effectively we build 
a distributed hash-association database (which content should remain intact 
even if we delete the downloaded files).

The general problem is trust: You have no definitive source which you can 
trust, so there are several possibilities for malicious nodes to exploit these 
circumstances (constantly sending wrong hashes etc). This is particularly nasty 
with new files if you use the amount of similar incoming hashes as a 
rating-system.
 You don't have this problem with the ed2k-chunk-hashes which you get from your 
ed2k-peers, as the master-hash is the hash of the concatenated chunk-hashes.

Any more ideas on how to reliably get associated hashes/identifiers?

-vnc