running around announcing that the
sky is falling, but, unless you have been
living under a rock, you will notice that,
indeed, the sky is falling. Not a day goes
by without a significant attack against
networked systems making the news,
and the Internet of Terror is leading the
charge in taking distributed systems
down the road to hell—a road that you
wish to pave with your good intentions.
Before I get to the question of encryption and key length, I would like
We are deploying a consumer Io T (
Internet of Things) device, with each device connected to a cloud service that
acts as the platform from which it will
be controlled. The device itself is not
dangerous: it is a simple, slimmed-down tablet to be used in hotel chains
to replace an alarm clock and TV remote, and to provide access to room
service. The device is battery operated,
rechargeable, and cheap enough that
hopefully no one will want to steal it.
Guests cannot load any information
into it, and—unlike a typical tablet—it
does not serve as a Web browser.
We have an engineer who seems
overly worried about the security of the
communication between the device
and the back end. We are working on
the alpha version of the system now.
All communication between the device
and the cloud is unencrypted, and no
user data crosses the network. Who
cares what TV channel you are watching or what you ate for breakfast? On
such a lightweight embedded device,
the battery-life cost of encryption is
significant and reduces battery life by
25% in our tests. We expect many users
will not replace them in their charging cradles, since most people cannot
remember to charge their own phones
every night; thus, battery life will be
very important to the project.
Even if we do turn on some encryption, we would like it to be as little as
possible, again, to preserve battery life.
I know a longer key is harder to break,
but it also means that we will be using a
lot more of the battery protecting what
is, in reality, data that is hardly a state
secret. What do you think is the right
level of encryption, if any, to use in
such a system, and how can we get the
annoying engineer to shut up?
Not So Secret
Dear Not So,
It is true that many security-focused engineers can sound like Chicken Little,
IoT: The Internet
If it seems like the sky is falling, that’s because it is.