[p2p-hackers] p2p in some place or other

[Alen Peacock]

On 12/12/05, Matthew Kaufman <matthew at matthew.at> wrote:
>
> This could be some external motivation like "I want anonymously-posted files
> about certain political views to be available for all to see" or "my
> corporate IT department says that we have to use this distributed
> collaboration tool"

  External motivation is good, but is it sufficient to provide some
sort of equilibria?  If not, it's just the prisoner's dilemma; the
vast majority of nodes disable caching because it is locally optimal,
regardless of the fact that this produces a globally non-optimal
solution.  In fact, it might be even worse: the local cache could be
exploited by malicious nodes to store data to the network.  For
example, instead of sharing my files from my own box, I just push them
all out to the cache and stop local sharing altogether.


> > If proactive caching were turned on by default in my p2p
> > filesharing client, don't I have a very real incentive to
> > turn this off in my own node to preserve bandwidth, disk
> > space, and perhaps limit any legal liability?
>
> In the general "filesharing" case? Absolutely. But that's not the only use
> for P2P technology or even P2P file transfer.

  Ah, but it doesn't matter if it is filesharing or not -- if the
system can arbitrarily push data to my cache, my
[bandwidth|disk|legal] resources are being consumed, regardless of
whether the application layer is doing filesharing, chat, video,
email, etc.  And if I can prevent access to these extra resources, or
if I can download an alternate client which promises better local
performance and less legal liability, why wouldn't I?

  I'll admit that maybe I'm just obsessing over this point for purely
academic reasons; maybe the majority of users simply accept the system
defaults and innocently engage in altruistic behavior that ends up
optimizing global performance.  Maybe they all just turn their caches
on because it is 'the right thing to do.'  Maybe no one writes
malicious software that takes advantage of [for example] a proactive
cache.  Maybe we shouldn't worry about it at all.

  But, isn't it more interesting to think about building systems that
have some fairness guarantees than building ones that don't?  Building
a proactive cache that isn't susceptible to these abuses might require
a trust/reputation sytem, which in turn requires a strong identity
system, etc. -- but isn't that where the real fun is anyway? :)

  Alen