Electrical Engineering MS Thesis Defense by Brent Rubell
Abstract:
While the Internet of Things (IoT) is set to grow to 40 billion connected devices by 2030, developing an IoT product is still incredibly complex. The process of developing a single IoT product requires a person (or team) to have expertise spanning firmware development, hardware development, and web development. Due to the complexity during the development process, IoT products are often single purpose, communicate using proprietary protocols to servers in unknown locations, and their functionality cannot be extended by a user after deployment. Research into creating frameworks that allow machine to machine (M2M) communication and simplified development, such as Firmata and ASIP, face limitations in efficiency, extensibility, and security.
This thesis proposes ESMP, an Efficient and Secure Messaging Protocol. ESMP is designed for bi-directional M2M communication, where both the server and the microcontroller use a common language to communicate. To do this, ESMP is combining Google’s Protocol Buffer format, the MQTT protocol, and security at the transport-layer.
ESMP messages use a “super message” design which wraps all sub-messages into a single schema to reduce the number of managed MQTT subscriptions. It comprises a network architecture using MQTT where the embedded device shares the same set of protocol buffer schemas with the MQTT broker. Security at the application layer is approached using username/password authentication; unique client identification, and packet data is SSL-encrypted. Whereas regular embedded firmware has predefined hardware behavior as part of its firmware, the ESMP client is a “blank slate” that receives commands from the ESMP broker. Using a RPC-like action mechanism, an ESMP client allows a ESMP broker to dynamically control its hardware. An open-source GUI tool allows users to visually construct and send protocol buffer messages to an ESMP client.
An overhead evaluation of the payload showed ESMP’s protocol buffer schema produced the smallest payload size when compared to XML, JSON, and plain-text data encoding. The latency evaluation showed ESMP’s RTT latency to be slower than the ASIP baseline, but with this trade-off justified because the device communicates over WiFI rather than wired Ethernet, allowing it to be deployed anywhere in the field. The viability of ESMP was proven by using ESMP to construct a real-world IoT application, a door sensor which sends its status to the ESMP
broker when it is open. Finally, the extensibility of ESMP was validated by adding new functionality to ESMP with minimal impact to device flash/RAM utilization.
ESMP demonstrates a viable solution for efficient and secure M2M communication for the IoT. It presents a way to extend the functionality of an IoT product without compromising security or data efficiency. The feasibility of this solution has been validated by its adoption into Adafruit’s WipperSnapper firmware, an open source IoT firmware deployed on thousands of devices, enabling users to build IoT products and projects without programming.
Lester W. Cory COnference Room, Science and Engineering Building (SENG), Room 213A
Dr. Hong Liu
508.999.8514
hliu@umassd.edu
https://umassd.zoom.us/j/93281343753?pwd=UWd5TGsweFpyMC9ydWhzaWErZnlndz09