Sensor networks like CeNSE are enormously complex and can cover huge geographic areas. They also span a wide range of applications that can require radically different overall design solutions.
That means that different CeNSE-type networks will also face very different issues of security and privacy, says Bill Horne, a Princeton-based research manager in HP’s Systems Security Lab.
“A network, for example, that consists of stakes that get stuffed in the ground with mini computers sitting on top,” he says, “will face very different vulnerabilities from one where you have microscopic, mobile sensors that get spread out over a big, constantly shifting area.”
However , says Horne, the same process can be applied to addressing the vulnerabilities of each.
Anticipating threats
“What you need to do is build a threat model,” Horne explains. These are designed to address security concerns from three main perspectives:
1. Confidentiality – to make sure data is kept private
2. Integrity – to make sure no one can change or corrupt the data being collected
3. Availability – to make sure people can't launch attacks (such as Denial of Service attacks) that bring down whatever is important to make the system run.
A threat model also imagines who might want to inflict damage upon a system. Such people could be competitors, angry employees, or locals wanting to steal devices for parts.
But in many cases, says Horne, “your most troublesome adversary will be nature. If you're creating a network out in the middle of the desert, say, and it's 140 degrees and you've got animals running around and wind and sand storms, those are going to be the main threats to the integrity of your system.”
New technological challenges
Running a threat model will often identify issues that can be addressed with existing solutions. But Horne expects CeNSE networks to expose a number of new research challenges, too.
“One issue that has already popped up,” he says, “is low-powered cryptography.”
Conserving battery power is a huge concern with remotely-located sensors. And yet the data they transmit will often need to be encrypted for security reasons, which is typically a computationally intensive activity. “So whether you can design new kinds of crypto algorithms that are power sensitive,” says Horne, “is a whole interesting research field.”
The intersection of privacy and security
While CeNSE-type networks need their own integrity, they also raise issues of privacy for people who are moving about within their orbit.
“Privacy is essentially another confidentiality issue,” says Horne, “only what you care about here is the confidentiality of a third party.”
Such concerns can be identified through building a threat model and to some degree mitigated by good system design. But in the end, says Horne, “it's largely a policy issue; in the sense that people need to know that they have some rights relating to their data and to understanding how it is being used and how it's being shared with other people.”
The OECD, he notes, has established Privacy Principles that define the rights citizens should have to their own data. From HP's perspective , says Horne, “for any application, we would take a very close look at how we're handing personally identifiable information and make sure that we're doing the responsible thing with that information.”
[Editor's note: for more on HP's research into privacy and cloud computing, read this post about EnCoRe]
Putting it all together
Addressing issues of security and privacy in any complex system is hard, adds Horne, and easy to get it wrong.
“Sensor networks are not just a single set of computers,” he notes. “It’s the sensor network, the communication network, the data centers, the people involved. And then all the different stakeholders that come into play each bring different security problems to the table.”
But HP has a centralized privacy organization, he notes, and a services arm with an established expertise in addressing security across the IT landscape.
“It's a complex problem,” says Horne, “and you need a company with the breadth of expertise that you find at HP to do it right.”
