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["L.G.Casado" <leo@xxxxxx>]

Hello,
El mié, 12-08-2015 a las 15:27 +0500, Ilshat Shakirov escribió:
> Hello,
> 
> > N-1, is set because there is one Trusted peer, does it?
> Yes, because trusted peer doesnt check itself.
>  
> > How is set X, random check yes/no?  
> > 
> I think yes. In the first impl of STrPe trusted peers checked every
> 255 received chunk.
> 
Why a TP does not check every chunk?
In a persistent attack, peers will be detected directly.
The random check could be seen as malicious peer performing  a kind of
selective attack.
> About current progress:> I've found a small bug in the initialization of big teams (i.e. 100 peers) with enabled STrPe-DS. In 2-3% of cases peer hangs up and do nothing.
Then, they should be expeled soon.
> Also, Ive prepared a raw data from STrPe experiments (Ive performed experiments with 100 peers, 1-2-4-8 trusted, and 10-25 malicious). And since trusted peers in STrPe checks chunks randomly from all the peers in the team, it can take long time to expel all the malicious peers. It happens because TP selects chunk to check from all stream, although it should select chunks from each peer.
I think to check randomly has no sense if trusted peer is in system
without resources limitations, which should be the case.
> If we implement this, then Juan will be right and number of TPs in the team won't have impact on mal. peer expulsion. Now, if we have more TP, we have more chances, that TP will check chunk from mal. peers and will exclude it.
Yes, checking them all, just on TP is enough for persistent attack, but
it is not the case for other attacks.
> Also, STrPe-DS don't have such problem, because I've implemented next
> logic:Every S seconds splitter selects new peer from all the team and
> TP from trusted peers and do 2 requests to gather complains from the
> team. 
> So, mal. peers will be excluded almost in the same time they ve sended poisoned chunks to TP.> 

Again, for persisten attack this is true, but not for the more
sophisticated ones.
> Thanks!
> 
Best,
Leo
> 2015-08-12 15:08 GMT+05:00 L.G.Casado > <leo@xxxxxx>> :
> > Dear Ilshat,
> > > > El mié, 12-08-2015 a las 12:04 +0200, L.G.Casado escribió:
> > > BC = 1 - M / (N - 1 + 1) = 1 - M / N,
> > > > Sorry, the formula was fine:
> > > > (N-M)/N= 1-M/N
> > > > Please, answer the other questions.
> > > > Thanks,
> > > > Leo


>