Device Identity Bootstrapping in Constrained Environments: A BLE-Based BRSKI Extension

In contrast to user authentication in the digital domain, device authentication entails distinct requirements and challenges. In the enterprise context, Internet-of-Things (IoT) devices must support strong identities to ensure secure and trusted operations. A critical first step in developing such systems is the secure bootstrapping of these devices. However, achieving trusted bootstrapping is challenging when Internet access is prohibited. In such environments, an identity must be provided to the device beforehand. The solution should also work with minimal human intervention in our scenario. To achieve this, we developed cBRSKI-PRM, a hybrid combination of BRSKI-PRM and cBRSKI. BRSKI-based communication between components is facilitated via Bluetooth Low Energy. We implemented the proposed solution on an ESP32 platform, ensuring reliable performance in both hardware and software while optimizing for low power consumption. Additionally, we identified and addressed several issues in the specifications of the employed protocols. We published all source code used in this project under the permissive MIT license. By combining and extending existing open protocols, we developed a highly assured bootstrapping process for IoT devices under minimal trust assumptions in constrained environments.