I've been working on a similar, but safer, system called Tethr.us (as in US, not USA) for the past 6 months or so. I'm at the point of looking for funding to build a prototype. It's a satellite modem (BGAN) with OpenBTS, wifi access point and a gateway server called Tethr.org. Any piece can be powered off individually via the admin UI. It has NO mesh networking and all radios, by default, run at ~100mW so they don't travel far enough to be a huge security risk. The onboard server provides DTN or sync services so that the system is useful if you just connect with a wire and only turn on the radios once in a while. On the backend, everything is optionally proxied out via TOR (to conserve bandwidth we don't do it on the gateway side, but we could). I've targeted it at journalists who understand the risks of running radios in a hostile environment, but anyone can certainly benefit. I know the limitations of BGAN and would love to replace it with something else, but the ubiquity, battery capacity and antenna size make it suited for this sort of work. If anyone is interested in hearing more, let me know and we can talk about it on another thread here or off-list. On Tue, Jun 14, 2011 at 11:25 AM, Michael Rogers <m--@gmx.com> wrote:

On 14/06/11 04:42, Julian Cain wrote:

...

On Jun 13, 2011, at 8:38 PM, Jan Brittenson <bson@rockgarden.net> wrote:

...

I think all you need is something that can be turned on at specific times, to get a message out. Then shut it off. People will have their phones on, then all of a sudden they get service, a text message or two, after which the service promptly drops again. A station only needs to be on long enough to get the message out.

... and to receive the acknowledgement regarding said message.

Acks may or may not be necessary, depending on the protocol. With a Usenet-style flooding protocol it's sufficient to transmit each message opportunistically to everyone you meet and discard duplicates - no acks are needed.

...

...

I think the main challenge is how to prevent a regime from hijacking the network. This will probably require an organized structure with isolation, redundancy, a revocation protocol, and careful safeguarding at the top.

Funnily enough I'd argue for the opposite approach - the way to make it robust isn't to safeguard the top, it's to have no top. ;-)

Imagine a completely distributed publish-subscribe network organised into "channels", where each channel's subscribers flood the channel's messages among themselves using a simple Usenet-like protocol.

How do we prevent agents of the regime from drowning such a system with spam?

Solution 1: Restrict who can post to each channel. (For example, by associating each channel with a public/private key pair - subscribers discard any messages that aren't signed with the private key.) That would create a bloggish/twitterish style of interaction where each channel would have one author (or a small group of mutually trusting authors) and an unlimited number of readers.

Solution 2: Peer moderation. In this model, any subscriber can post signed messages to a channel, but each subscriber will only forward messages signed by authors who that subscriber has manually marked as not being spammers. Thus new authors can't reach a wide audience until they've won the trust of some other subscribers.

Solution 2 involves more work for subscribers than solution 1, but it allows multi-way discussions, whereas solution 1 could potentially devolve into people shouting past each other. Fortunately both solutions require similar infrastructure, so we can build them both into the same system and see which one people prefer.

...

The number of dissident operated devices need only outweigh a "regime" in order to protect the network. The same rules apply to most overlay networks.

Not really - most P2P and wireless overlays can be jammed by a small number of malicious nodes, including the mesh protocols that have been discussed for these "internet in a suitcase" type ideas.

Cheers, Michael _______________________________________________ p2p-hackers mailing list p2p-hackers@lists.zooko.com http://lists.zooko.com/mailman/listinfo/p2p-hackers

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