On Sat, Jul 13, 2013 at 12:36 PM, Mitar <mmi...@gmail.com> wrote: > Hi! > > I am a bit concerned with the CJDNS hype I am observing around. I do > like that decentralized Internet is getting momentum, but I am > concerned if CJDNS is really the way to achieve that. From its > whitepaper it seems that it is susceptible to a Sybil attack:
After this thread started I wrote to the author— as I'd pointed out before I had the same concerns initially but had spoken to him and basically came away with an impression that he was aware of the problem space and wasn't doing the dumbest possible thing as a result— and there was at least a fighting chance that the system addressed the issue, but I didn't care (or, really, have time) to understand more at the time, so I couldn't write an actual explanation. He seems to be having some problems getting onto the list, so he sent me a response to reflect up to it: ----- CUT HERE ----- The answer to ID clustering attacks is that cjdns is just really lazy, it routes to the physically nearest node whose ip address is numerically closer to the destination than your own (based on KAD). Since the physical topology is friend-to-friend, the attacker is forced to have a relatively tight cluster of nodes in physical space, they can pollute their own neighborhood but not the whole network. Pollution of one physical neighborhood would likely lead to them being de-peered by their "friend" who gave them the link. Re the recursive routing, it has two options. You can send direct to the destination at the switch level or you can forward to any node in the network and ask them to forward to the destination. The nodes between you and the one you asked to forward will have no access to the IPv6 dest address and if the one you are forwarding to us unfriendly, you use someone else. We've considered changing this to improve scalability but I can't figure out how to preserve this guarantee. The most scary general attack on the idea is a node who drops 10% of the packets sent through them. I don't know how to detect it statelessly and they can do quite a bit of damage. Again though the physical reality of the network comes in to play. The nodes which carry the majority of the traffic are heavily peered core nodes and the operators of such are unlikely to intentionally attack the network, this is the same logic which holds BGP together despite it's painful frailty. Hope that helps Thanks, Caleb -- Too many emails? Unsubscribe, change to digest, or change password by emailing moderator at compa...@stanford.edu or changing your settings at https://mailman.stanford.edu/mailman/listinfo/liberationtech
