Securing the Internet of Things - or how light bulbs can spy on you

What happens when clouds of sensitive data collide

Data from the device doesn't have to be encrypted just once and then sent all the way to the cloud; the flow of information can be segmented and protected within these shorter paths. This allows the data to be secured between just the device and a home hub or another trusted third party called a security manager. The hub and security manager can encrypt the data again after deciding which cloud service will receive the information.

A security manager in this case is a server defined by the Weightless Special Interest Group (SIG). These guys are the brains behind the Weightless machine-to-machine communications standard, which will initially operate in White Spaces - the chunks of radio frequency now free to use after the death of analogue TV.

Weightless-compatible devices chat to each other and their manager in their own separate network, and are not reliant on a home hub nor a broadband connection. The manager could be run by a network provider, a hardware manufacturer (say, Bosch), a utility (such as Scottish Power) or the Weightless SIG itself.

A Weightless-SIG-hosted security manager passes device data to the company providing the service (be that Scottish Power or whomever) and take instructions from the user if he or she wants to change providers.

When it comes to the cryptography itself, Nordic Semiconductor's Daniel Ryan explained how its communications chips had evolved; security is a secondary feature of the short-range radio electronics made by Nordic for numerous computer keyboards and mice.

Early versions simply had a crypto-key stored in the wireless keyboard and the USB receiver dongle; bytes of data representing the key presses were trivially XORed with the key to obfuscate the transmission, a solution which was both expensive and insecure. The next version added a counter, to prevent replay attacks, and used AES rather than XOR, but it still required unique keys to be programmed into the devices at manufacture (an expensive process) and was vulnerable to analysis given the non-random nature of typed text.

The third design requires the keyboard to generate a random crypto-key for each dongle it talks to; before this key is sent to the receiver, it is encrypted using a secret common to all of Nordic's Gazell chips. That shared secret is never used again between the keyboard and the dongle; the now randomly padded communication is subsequently encrypted with the new key, which is remembered by the keyboard and the dongle forever. For complete security a PIN is added during pairing, and the transmission power is turned down during pairing to reduce the chance of being sniffed. Lastly, the source code for the whole lot has been thrown open for public scrutiny.

Those changes aren't all in response to customer requests, or hack attacks, but were put in place in an attempt to build confidence in the security of the product even if incidents of wireless keyboard sniffing are all but unknown. It would only take one public case to dent that trust, perhaps fatally.

Mandated data protection, coming to a light bulb near you

The R&TTE regulations, required for the CE mark, already request that manufacturers "incorporate ... safeguards to ensure that the personal data and privacy of the user and of the subscriber are protected", but drafted updates turn that request into an obligation. Thus, cryptography will be mandated in any of the 50 billion things used by people or households (as opposed to cows, sheep, streetlights, etc).

But the big question which remains is how it's all going to be paid for, which in turn defines the architecture and thus the security that can be applied.

The manufacturer of a boiler might add a lifetime's cloud support to the price of its product, but as CSR's Robin Heydon pointed out, when one's thermostat checks the weather forecast from Accuweather it's not going to see the advertising that pays for the service, so machines will have less free data to work with than their eyeball-touting masters.

ISPs might start selling smart hubs that aggregate data for transmission, but today's heating and lighting systems are built into houses well before the ISP has been selected, so cloud-based management of Hue lightbulbs or Nest thermostats will need to be transferable between owners and service providers.

All this is predicated on the assumption that our homes are going to become hives of connectivity with machines chattering away to each other day and night, sometimes saying nothing at all other than a "hello, world" just to make sure robbers don't take the lack of network traffic as an indicative of our absence.

If we ignore the Internet of Things, pretending it's not going to happen, then likely it will emerge through mandated smart meters and kids' toys. Only then it will come without the privacy safeguards, owner's control and security which the chaps and chapesses in Cambridge spent so long debating. ®