Energy-efficient encryption for the internet of things (IOT)

Internet of things (IoT) world map with connected devices
Internet of things (IoT) world map with connected devices

Public-key encryption protocols are complex, and in computer Networks, they’re executed by software. But that will not work in the net of things, an envisioned network that would connect many different sensors — embedded in appliances, vehicles, civil structures, production equipment, and even livestock tags — to servers that are online. Embedded sensors that will need to maximize battery life can’t afford the energy and memory space that software execution of encryption protocols would require.

MIT researchers have built a new chip, hardwired to perform Public-key encryption, that consumes only 1/400 as much electricity as software execution of the very same protocols would. Additionally, it uses about 1/10 as much memory and executes 500 times faster. The researchers describe the chip at a newspaper they’re presenting this week at the International Solid-State Circuits Conference.

Like most modern public-key encryption systems, the researchers’ chip Uses a technique known as elliptic-curve encryption. As its name suggests, elliptic-curve encryption relies on a form of mathematical function called an elliptic curve. Previously, researchers — including the exact same MIT group that developed the new chip — have built chips hardwired to manage particular elliptic curves or families of curves. What sets the new chip apart is that it is designed to handle any elliptic curve.

“Cryptographers are coming up with curves with different properties, “There is a whole lot of debate regarding which curve is protected and which curve to use, and there are numerous governments with different criteria coming up that talk about different curves. With this processor, we can support all of them, and hopefully, when new curves come together in the future, we can encourage them as well.”

To make their general-purpose elliptic-curve chip, the investigators Decomposed the cryptographic computation to its constituent components. Elliptic-curve cryptography relies on modular arithmetic, meaning that the values of the amounts that figure in the computation are assigned a limitation. If the result of some calculation exceeds that limit, it is divided by the limit, and only the remainder is preserved. The secrecy of the limitation helps ensure cryptographic security.

Among the computations to which the MIT chip devotes a Special-purpose circuit is thus modular multiplication. But because elliptic-curve cryptography deals with big amounts, the chip’s modular multiplier is massive. Typically, a modular multiplier might be able to handle numbers with 16 or possibly 32 binary digits, or bits. For larger computations, the results of distinct 16- or 32-bit multiplications would be integrated by additional logic circuits.

The MIT processor’s modular multiplier can handle 256-bit numbers, however. Eliminating the additional circuitry for incorporating smaller computations both reduces the processor’s energy intake and increases its rate.

Another key operation in elliptic-curve cryptography is known as inversion. In previous chips dedicated to elliptic-curve cryptography, inversions were performed by the very same circuits that did the modular multiplications, saving chip distance. But the MIT researchers rather equipped their chip using a special-purpose inverter circuit. This raises the chip’s surface area by 10 percent, but it cuts the energy consumption in half.

The most common encryption protocol to use elliptic-curve In fact, the whole protocol is hardwired in the MIT researchers’ chip, which radically reduces the amount of memory necessary for its execution.

The chip also features a quad-core chip that can be used Together with the dedicated circuitry to execute additional elliptic-curve-based-security protocols. But it may be powered down when Not being used, so it does not undermine the chip’s energy efficiency.