Security is one of the hot topics today in the Internet of Things (IoT). There have been well-publicized security breaches of consumer devices that include hijacked video from wireless baby monitors being posted on the Internet and home automation systems that reveal whether a home is occupied or not. A number of systems have been breached just to demonstrate their vulnerabilities. Less well publicized are security breaches of industrial equipment with much more severe consequences. These are rarely made public for obvious reasons.
At first glance, it would seem that the existing security mechanism for the Internet and corporate networks would be an easy solution for IoT security. There are several problems with this. First, IoT applications only require security that is “good enough” for the specific application. Just like you don’t need razor wire and guard towers to keep your dog in the yard and don’t want to rely on a four foot yard fence to keep the prisoners in a maximum security prison, the level of security for an IoT product needs to be based on the needs of the application (often basic privacy rather than real security).
Consider data encryption for network transfers as an example of why existing security mechanisms generally do not work well for the IoT. Encryption standards typically target applications that require extremely high levels of security such as financial transactions and military or national security communications. These encryption standards are severe overkill for most IoT applications and present significant problems for small, battery-powered IoT devices. An encryption algorithm may require upwards of 4 KB of code space, which is as much or more than many otherwise suitable microcontrollers might have. Many encryption standards rely on multiple rounds of encryption. The time it takes to perform the encryption could be several times longer on a small micro than the time it takes the micro to perform its main tasks. Most common encryption standards rely on 16- to 32-byte keys to help ensure data security. For many IoT devices, these key lengths could increase the length of their network messages by a factor of 4× to 8× or more. The execution time and added network traffic can quickly chew-up precious battery capacity, increasing the size and cost of a product. The extremely high level of security provided by these encryption algorithms is what drives the large code size, long execution times, and high message overhead that makes them inappropriate for most IoT applications. Hardware encryption addresses the code size and execution time issues but still suffers from high message overhead.
The other major problem with using existing security mechanisms is IoT developers typically don’t have network security experience. There is a certain mindset and expertise required to develop IoT products and a completely different mindset and expertise required to be a security expert. The time required to develop these security mechanisms in-house could take several times longer than the basic product development. Several companies have recognized this problem and have recently introduced security framework products to be incorporated into IoT devices. True end-to-end security requires much more than just passwords and data encryption, and these framework products address other needs like key management and protection against common network attacks. These security frameworks may well be the future of IoT security, but to be widely adopted, they have to be right-sized for IoT devices.
When selecting the wireless technology to use in an IoT product, things like distance, bandwidth, cost, and physical size have to be considered. Words and phrases like “streamlined” and “light weight” need to be kept in mind when assessing security solutions for IoT products. A feature-rich security framework product might be appealing, but many IoT devices provide simple functions and don’t need a plethora of features. They also can’t afford the memory space and execution time overhead (and power consumption) imposed by these unneeded features. Whether future IoT products are based on a security framework or in-house developed security, there will not be a one-size-fits-all solution. Security for successful IoT products will be right-sized for the hardware resources available and the needs of the application.
Mike Lease is a hardware/firmware engineer with more than 30 years of product development experience, mostly in embedded products. He developed a number of battery-powered, wirelessly connected devices before “IoT” became a common buzzword, and several more since then. Mike enjoys taking on tough challenges and has recently developed a fascination with generating random numbers. In 2013 he founded CMicrotek (www.cmicrotek.com) to develop a family of ultra-low current measurement products primarily for developers of battery-powered products. Mike recently launched LSE Technologies, a provider of lightweight stream encryption software for M2M and IoT applications.