Re: [Hipsec] Network-bound puzzles for HIP?

[Thierry Moreau <[e-mail]>]

Miika Komu wrote:
> Hi Thierry,
> 
> how do you register the network puzzle to the URI? Unlike the current 
> HIP puzzle, your solution requires a third party? And it couples HIP 
> control plane with e.g. CoAP (since you're talking about URIs)?
> 

These are "implementation details" at this point, and anyway someone 
else contribution is just as relevant as mine. A third party appears not 
essential.

> A decoupled and more standards-compliant solution with a HIP-specific 
> third party could to assume a rendezvous or relay server, which drops 
> messages until some time period. This "some" could be defined when a 
> host registers to rendezvous or relay server or updates its 
> registration. The drawback here is that the initiator will not receive 
> any time value for waiting (unless the rendezvous sends NOTIFY).
> 

That may qualify as "someone else contribution" and could be relevant.

> I am not an expert, I believe current wireless sensor networks 
> communicate through sink or gateway, so DoS protection is not really 
> necessary for the sensors. However, the IoT vision is to have end-to-end 
> connectivity for the sensors, so this may change in the future. Any 
> thoughts on this?
> 

As I understand it, the DOS protection benefits the responder, but the 
CPU energy cost is allocated to the legitimate initiators 
indiscriminately (hence the sensor end-point concern).

> P.S. Are you aware of any patents related to network puzzles?
> 

Not aware of anything from third party in this respect. I disclosed the 
proposal to the HIP mailing list assuming this would be a public 
disclosure (through the mail archive) and I did not file any patent 
application on this proposal.

Regards,

-- 
- Thierry Moreau


> On 11/27/2012 07:03 AM, Thierry Moreau wrote:
>> Hi,
>>
>> I find quite interesting the active development of HIPv2 drafts. From an
>> applied cryptography perspective, I appreciate this state-of-the-art
>> secure protocol development.
>>
>> Nonetheless, I am very novice in the design of puzzles for DOS attack
>> mitigation. But I have this idea of network-bound puzzle so that the
>> battery life of sensor devices is preserved.
>>
>> Very roughly ...
>>
>> The network-bound puzzle is a pair <URI,time0,time1>
>> If time0>=time1 the solution is zero
>> Otherwise, the solution is obtained from the "URI server" (using an
>> plain UDP query) at a time no earlier than time1 (which the HIP
>> initiator may guesstimate as now+(time1-time0)
>> (I use absolute times such that the URI server need not be synchronized
>> with the responder).
>>
>> UDP queries to the URI server simply carry some value timeX (discrete
>> resolution)
>> The URI server simply answers UDP queries with either
>> a) solutX (for timeX>=now), else
>> b) delayed UDP response solutX (if timeX in near future and the URI
>> server is not currently under heavy load), or else
>> c) some "REQUEST TOO EARLY" negative response.
>>
>> In practice, some secret pseudo-random sequence defines the successive
>> solutions. I would guess a timeX resolution of 0.1 second would allow
>> DOS attacks mitigation in low to medium throughput HIP responder hosts,
>> but this is only from intuition.
>>
>> The HIP responder may need a special arrangement with the URI server to
>> learn the responses in advance (or on a priority basis during a DOS
>> attack). I guess the two could be the same system (the URI server needs
>> not be "trusted").
>>
>> ... end of rough idea.
>>
>> Was this ever envisioned? Were the practicalities ever looked at?
>>
>> Anyway, just my little suggestion.
>>
>>
>> Yes, I did look at
>> http://www.ietf.org/mail-archive/web/hipsec/current/msg03122.html
>> (Memory-bound puzzles in BEX)
>> and the reference by Rivest et al. (which does not address the DOS
>> mitigation as it is understood nowadays but has something along the URI
>> server idea for "timed-released crypto").
>>
>> and
>> http://www.ietf.org/mail-archive/web/hipsec/current/msg03565.html
>> (New Version Notification for draft-hummen-hip-middle-puzzle-00.txt)
>>
>>
>> Regards,
>>
> 
>