Software development kit secures over-the-air firmware updates
Firmware updates over-the-air will be accompanied by a secure signature that ensures the update comes from a verified and trusted source. This is a feature in the nRF5 SDK (software development kit) v12.0 from Nordic Semiconductor.
Secure signatures to authenticate that only updates coming from a verified and trusted source can be made on a given device. The SDK supports the Arduino development kit used with the Nordic nRF52832 SoC-based Arduino Primo base board and features a CMSIS configuration Wizard that allows graphical configuration in Keil. It also offers Bluetooth low energy Continuous Glucose Meter (CGM) profile support, and provides optimised Floating Point Unit execution
In operation, a classic public/private key security structure is employed whereby public keys are distributed and private keys remain solely with the sending party, thus ensuring one-to-one security. Using ciphers to create keys in the SDK can be executed in various ways, including Nordic-authored examples using, for example, ECDH using the P256 curve to establish secure connections in Bluetooth low energy. (The company has also reserved two dedicated 16bit UUIDs with the Bluetooth SIG (Special Interest Group) for use with signed and unsigned firmware.)
It also supports secure device firmware updates (DFU) application development with a suite of cross-platform PC tools and additionally mobile tools for Android and iOS.
If a secure OTA-DFU (over-the-air device firmware update) is interrupted, a ‘resume-from-failure’ feature is said to allow updates to resume from the last known-good point and complete instead of re-starting the entire upgrade process from scratch.
Floating Point Unit (FPU) execution leveraging the FPU instruction set capabilities of the ARM Cortex M4F in the nRF52832 has the potential to save considerable processing time and software complexity when dealing with the floating point numbers increasingly necessary and common to many modern product and application software algorithms, says the company.