Smartphone-Readable Time Response-Encoded Phosphorescent Labels and Authentication Protocols for Internet of Things Applications

In this paper, we propose a lightweight authentication and identification protocol based on different phosphorescent Strontium aluminate color labels. The excitation sources are pulsed UV LEDs emitting at 365 nm and 385 nm, causing different RGB-dependent time responses of the label that are measured using a smartphone recording at 30 FPS. The rise and decay time responses as measured by the red (R), green (G) and blue (B) pixels were separately analyzed and were found to follow a power law with individual parameters depending on the excitation wavelength, pulse duration and duty cycle, which serve as security features and are suitable for authentication purposes in IoT applications. Our solution uses simple cryptographic functions such as HMAC and XOR. We performed a security analysis of our protocol to prove its resistance to known attack vectors. The proposed scheme has minimal computation and communication costs and can be deployed on resource-constrained Internet of Things devices.