SecuCode: Intrinsic PUF Entangled Secure Wireless Code Dissemination for Computational RFID Devices

Abstract

The simplicity of deployment and perpetual operation of energy harvesting devices provides a compelling proposition for a new class of edge devices for the Internet of Things. In particular, Computational Radio Frequency Identification (CRFID) devices are an emerging class of battery free, computational, sensing enhanced devices that harvest all of their energy for operation. Despite wireless connectivity and powering, secure wireless firmware updates remains an open challenge for CRFID devices due to: intermittent powering, limited computational capabilities, and the absence of a supervisory operating system. We present, for the first time, a secure wireless code dissemination (SecuCode) mechanism for CRFIDs by entangling a device intrinsic hardware security primitive-Static Random Access Memory Physical Unclonable Function (SRAM PUF)-to a firmware update protocol. The design of SecuCode: i) overcomes the resource-constrained and intermittently powered nature of the CRFID devices; ii) is fully compatible with existing communication protocols employed by CRFID devices-in particular, ISO-18000-6C protocol; and ii) is built upon a standard and industry compliant firmware compilation and update method realized by extending a recent framework for firmware updates provided by Texas Instruments. We build an end-to-end SecuCode implementation and conduct extensive experiments to demonstrate standards compliance, evaluate performance and security.

Building Secure SRAM PUF Key Generators on Resource Constrained Devices

“…In majority voting (MV), given q repeated response measurements under an operating condition, the response value ('1'/'0') enrolled is that which shows no less than q 2 measurements; with q an odd integer. In reliable response pre-selection (PreSel), each PUF response under an operating condition is repeatedly measured i times, only response bits that exhibit 100% reliable regeneration (all '1's/'0's) are selected for use and enrollment-a detailed methodology with a resource limited device is in [22].…”

“…In fact, most IoT devices do not have FPGAs but operate using MCUs. Further, to the best of our knowledge, there is only one end-to-end software PUF key generator implementation on a low power computing platform in the form of a highly resource constrained and batteryless device that relies only on harvested RF energy for operations [22].Therefore, we aim to provide a simple and timely guide to the Ubiquitous Computing community for realizing PUF based key generators to benefit from their inherent key security. In particular:…”

Hash Functions and Benchmarks for Resource Constrained Passive Devices: A Preliminary Study

“…Hence, only within the period highlighted in light blue, can the Load be actually powered. Such a period is called the intermittent power cycle (IPC), which is short and fragmented over time in practice [9]. Fig.…”

“…In this context, a low-power sleep state [31] can be used to intermit execution to allow the reservoir capacitor restore its energy. This intermittent execution model (IEM) can realize task execution in an energy limited setting [9]. First, it stretches the time frame to complete the task and hence allows the energy harvester to collect more energy.…”

“…It is hoped that such benchmarks will provide a useful guide to engineering crytographic solutions for resource constrained devices. We also briefly discuss an execution model for hash primitives based on [9] for operating under intermittent powering. We begin with an illustration of the unique challenges posed by intermittently powered and resource limited devices.…”