On Sat, Aug 27, 2011 at 11:39 AM, David Barrett wrote:

Perhaps I misunderstand Tahoe. Is it intended for groups to share data (eg, I add a file, you discover and download it), or is it purely for me to backup my data?

If the latter -- if it's purely for individual backup -- then I agree there's no risk from the RIAA: you're not sharing it so there's no problem.

But if the former -- if there's some way I can join your Tahoe cluster and access data that's already there -- then would you be willing to let the RIAA join your cluster with the keys to access the data there?

I think Tahoe fits either use case of a shared file repository or a distributed backup system. There are two levels of credentials you can share: the introducer furls, which grant access to your grid, and the rootcap for a particular directory on the grid, which grants access to a specific set of files. By Tahoe's design you should be able to give the RIAA the introducer furls to your grid. They can then create directories and store data on your grid, and will accept encrypted chunks of files from other peers. However, unless they actually have a rootcap for directories containing infringing content, they have no way of knowing whether or not the chunks they receive from other peers contain this data or not, since it's encrypted.

Because for something like Tahoe to work on a global scale, eventually you're not going to know with certainty all the other members -- and any one of those could in fact be the RIAA trolling for people to sue.

I'm envisioning a system where there wouldn't be an encrypted introducer URL to gain access to the grid, instead additional methods to provide a web of trust and collaborative filtering of particular peers would be used to prevent abuse. However, I think Tahoe's rootcap system is still essential. Cryptographic credentials would be required to access any data on the grid. For example, is it possible to determine who (username or IP) added the

content in the first place?

To my knowledge Tahoe doesn't log which nodes are responsible for the creation of content on the grid. Instead there are rootcaps which control read and write access to directories on the grid, and anyone with the "writecap" can add content to a particular directory. I may be mistaken as I have just started using Tahoe. In the system I'm envisioning, the anonymity of who created a particular file would definitely be preserved.

Is there some way to differentiate between when a node is requesting a specific piece of content from you, versus when it's just rebalancing some tree?

If so, then it's limited to groups of trusting friends -- still a great tool, but not a vast treasure of human knowledge as it sounds like you want to build.

But if not, if it's truly impossible to know whether a node is downloading and storing something because the user actually wants it or because the system forced them to get it unaware, then that could be a pretty good defense against overzealous copyright enforcement.

Though I wonder if a simpler model is to just start with something like BitTorrent, except every time you download anything, you also download something else randomly. So half of the content you download/seed is what you actually picked, and the other half is random. Then there's no way from the outside to tell which was for you, versus which is caching random content to increase the uptime and performance of the whole system.

I'd certainly agree BitTorrent could be the underlying technology underlying this system, layering the discovery and crypto on top of a BitTorrent-based system underneath, although I'd prefer it has more filesystem-like semantics like Tahoe. Perhaps BitTorrent with an "earliest-first" instead of "rarest-first" chunk selection mechanism would work. -- Tony Arcieri _______________________________________________ p2p-hackers mailing list p2p-hackers@lists.zooko.com http://lists.zooko.com/mailman/listinfo/p2p-hackers ----- End forwarded message ----- -- Eugen* Leitl <a href="http://leitl.org">leitl</a> http://leitl.org ______________________________________________________________ ICBM: 48.07100, 11.36820 http://www.ativel.com http://postbiota.org 8B29F6BE: 099D 78BA 2FD3 B014 B08A 7779 75B0 2443 8B29 F6BE