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Re: flow label demultiplexing


El 18/04/2005, a las 18:54, Iljitsch van Beijnum escribió:

On 18-apr-05, at 18:21, marcelo bagnulo braun wrote:

So, when you use CGA capabilities of the address, the CGA parameter data structure is exchanged upfront and it contains the public key.

Next, the node can use a new address (that was not included in the CGA parameter data structure) because it can authorize it by signing it with the private key corresponding to the CGA. Moreover, such signature could even be included in a packet that contains the new address as source address (i think)

But what exactly is signed here? I guess the whole packet, including the source address.

As i understand it, the new locator introduced in the set need to be signed. I guess we will need to add some additional context information to avoid reply attacks, and so one, but basically, the new alternative locator is signed with the private key associated to the CGA being used as identifier

A man in the middle would be able to modify anything that isn't signed. And even then, accepting a packet from an unknown source is dangerous because it can lead to a DoS against the CPU.

but i am not sure you could avoid DoS attacks from on path attacker... i mean, as soon the attacker discovers the context tag, he will be able t make the peer to verify some signatures, even though these don't verify, right? I mean, if we use public key technology, i guess there will risk of on path attackers dosing....


A system where the receiver challenges the sender would be MUCH better because that way we have return routability before spending serious CPU time.


Yes, this would make things better w.r.t. to on path dosers.... i guess it has the cost that you need to perform the reachability test before accepting packets from unverified locators, which may add extra latency.
I guess is part of the tradeoffs we need to start evaluating.

Regards, marcelo