Re: [CGA-EXT] Possible DoS attack to DAD in SEND ?

"Laganier, Julien" <> Tue, 01 December 2009 00:20 UTC

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From: "Laganier, Julien" <>
To: Tony Cheneau <>
Date: Mon, 30 Nov 2009 16:19:54 -0800
Thread-Topic: [CGA-EXT] Possible DoS attack to DAD in SEND ?
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Subject: Re: [CGA-EXT] Possible DoS attack to DAD in SEND ?
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Hi Tony,

Tony Cheneau wrote:
> [...]
> > The probability that two nodes ends up generating the same public-
> > private key should be zero unless the public key scheme is broken, so I
> > think when a node receives a SEND protected message where the public
> > key is the same as its own, the node MUST assumes the message was sent
> > by himself and MUST discard the message.
> That's another possibility. However, we should be careful that other
> public key scheme are not used. Such as the ring signature algorithm
> proposed in [1] (it's mainly a research paper), but all the node will
> share the same Public Key (hence address), and this is an expected
> behavior. One could argue this was useful to solve the ND proxy case
> (which is now solved differently), but I think it might also be a
> solution to anycast related issue SEND.
> To sum up, I'm OK to check for identical Public Keys, but I would
> rather see a comparison on more data (Public Key + Nonce + Timestamp).
> Does that seem reasonable ?

Hmm, for anycast there shouldn't be any DAD involved since an inherent characteristics of an anycast address is that it is shared and therefore duplicated. 

So maybe we can specify that a node receiving a DAD NS where the public key is the same as its own MUST assumes the message was sent by himself and MUST be ignored for the purpose of DAD?