Secured by hardware client-server communication based on NB-IoT technology

A significant growth of the number of embedded systems connected to the cloud services in the recent years has brought numerous new applications, but also exposed the IoT ecosystem to new threats and challenges in the security domain. The well-known and widely used security protocols such as SSL and TLS address these challenges successfully. However, they were primarily designed to protect the web traffic in a context where the bandwidth usage and computational power are not a big issue. In a case where massive-scale IoT connectivity is a requirement, it is of critical importance to optimize the bandwidth usage, without compromising the overall level of security. Our solution is presented in this paper, where we combine a low-bandwidth NB-IoT communication module with a hardware security element, in order to achieve secure connectivity to the cloud services, while reducing the communication overhead and offloading the computationally difficult security algorithms from the host MCU. By implementing the most recent version of TLS (v1.3) with an ECC-based key exchange scheme, we achieve 60% of reduction in the communication overhead during the handshaking phase in comparison to the widely used RSA-based TLS implementations.