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How to Design Wireless
Security Mechanisms
Manel Guerrero Zapata
<[email protected]>
Mobile Networks Laboratory
Nokia Research Center
Introduction
Problems in our research area:
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Not much to be implemented in the near future.
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Researchers do not have enough background
(routing protocols and security in wired networks).
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Too many people needing to publish papers in order
to get a PhD.
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Too much simulation, not much analysis.
Tamper resistant devices
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There is no such thing as a tamper resistant
device. (See Anderson & Kuhn "Tamper Resistance - a Cautionary
Note" & "Low Cost Attacks on Tamper Resistant Devices")
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Trying to combine symmetric cryptography
solutions with tamper resistant devices to create
the same result provided by alternatives that use
asymmetric cryptography does not make sense.
Misbehaving detection schemes
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It is quite likely that it will be not feasible to detect
several kind of misbehaving (specially because it is
very hard to distinguish misbehaving from
transmission failures and other kind of failures).
It has no real means to guarantee the integrity and
authentication of the routing messages!
With all this being common knowledge, it is amazing
that there are some people writing papers on top of this
idea (like the guys from EPFL Lausane).
Systems with unrealistic requirements
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MAC addresses identify unquely a node.
Every node should have some means to know
its geographic position.
There is a central server that is available by all
the nodes.
There is a tight time synchronization between
all the nodes of the network (the latest craze using TESLA
by Dave Johnson, Perrig and Hu).
Complex systems that
use fancy mathematics
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With mathematics you can hide the fact that,
actualy, your system does not work at all. Just
use a lot of formulas.
My favourite example is 'Securing Ad hoc
Networks' by Zhou & Haas. A distributed CA
that does not work if there are only two nodes
in a network partition. (Although is good in that recognizes the
non-feasibility of the central server approaches).
So what's the right way?
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Securing routing messages vs data messages.
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The scenario that is going to protect.
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The security features that this scenario
requires.
The security mechanisms that will fulfill those
security features.
Analisis
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The analysis of requirements: Whether the
security features are enough for the targeted scenario.
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The analysis of mechanisms: Whether the security
mechanisms are indeed fulfilling all the security
requirements. When doing this, it will be found that there are still some
attacks that can be performed against your system. Some of them, typically,
aren't avoid because a trade off between security and feasibility.
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The analysis of feasibility: Whether the security
mechanisms have requirements that are not feasible in the
targeted scenario.
That's all
Thank you for your atention.
More info about SAODV in:
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